Sunscreen cosmetic and method for manufacturing the same

Abstract

To provide a sunscreen cosmetic having excellent safety and an excellent ultraviolet protection effect and less coloration and to provide a method for effectively producing the same.SOLUTION: There is provided a sunscreen cosmetic which contains ferulic acid (A) as fine particles in an oil phase, wherein the median diameter (D50) of the ferulic acid particles is 0.01 to 10 μm and the content of the ferulic acid particles (A) component is 1 to 30 mass% based on the whole cosmetic. In addition to ferulic acid, γ-oryzanol can be contained, which further improves the ultraviolet protection effect. The sunscreen cosmetic can be formed in the form of an oil-in-water emulsion cosmetic, a water-in-oil emulsion cosmetic, an oily cosmetic, a two-layer-type cosmetic in which a water phase and an oil phase are separated, an aerosol cosmetic or the like. The sunscreen cosmetic can be efficiently produced by wet-pulverizing ferulic acid (A) in the presence of an oil agent to prepare a dispersion of fine ferulic acid (A), followed by mixing the resulting dispersion with other components forming an oil phase.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a sunscreen cosmetic containing ferulic acid as an ultraviolet protection ingredient and a method for producing the same. [Background technology]

[0002] Traditionally, inorganic UV scattering agents such as zinc oxide, titanium dioxide, and cerium oxide, as well as various organic UV absorbers, have been commonly used as ingredients to provide high UV protection to cosmetics. Organic UV absorbers have advantages over inorganic UV scattering agents, such as being easier to spread on the skin and not leaving a heavy finish. However, because they are chemically synthesized organic substances, there are concerns about the risk of toxicity to the skin. Therefore, in Japan, the Minister of Health, Labour and Welfare has established a positive list of UV absorbers that can be used in cosmetics, and ingredients listed on this list are permitted to be included in cosmetics within specified limits. Ferulic acid is one of the few UV absorbers listed on the positive list that can be obtained from natural plant oils.

[0003] Ferulic acid is a substance widely present in many plant organs, primarily as a precursor to lignin, which forms the seed cells and cell walls of plants such as rice, wheat, vegetables, and citrus fruits. Industrially, it can be obtained by hydrolyzing γ-oryzanol contained in rice bran, etc. While such ferulic acid is known to be usable in various cosmetics such as skincare products, makeup bases, and sunscreens, in the manufacture of cosmetics, due to its poor solubility in water and oil, it is often neutralized with a base and used as a water-soluble ultraviolet absorber. However, even after neutralization, ferulic acid has low solubility in water, and increasing the amount of the neutralized product inhibits the effect of water-soluble thickeners, causes significant discoloration, and is prone to discoloration due to light and temperature, making it difficult to incorporate ferulic acid at high concentrations.

[0004] Various methods for using ferulic acid as a cosmetic ingredient have been developed over time. For example, Patent Document 1 discloses an inclusion compound of ferulic acid and γ-cyclodextrin (see Claim 1) and an ultraviolet-preventive cosmetic containing the inclusion compound (Claim 2). It states that the inclusion compound improves upon the drawback of ferulic acid, which is prone to discoloration due to light and heat, and that the cosmetic cream containing the inclusion compound is stable against ultraviolet light (see Paragraph 0022). However, because the ferulic acid content in the ferulic acid-cyclodextrin inclusion compound is small, it is difficult to incorporate ferulic acid into cosmetics at high concentrations using this compound. Furthermore, because cyclodextrin is water-soluble, cosmetics containing the ferulic acid-cyclodextrin inclusion compound have the problem of being easily washed away by sweat and water.

[0005] Furthermore, Patent Document 2 discloses a method for surface-treating pigment powder with a water-poorly soluble organic acid compound by dissolving a pigment powder in an aqueous solution obtained by dissolving a water-poorly soluble organic acid compound as a salt in water under basic conditions, and then making the aqueous solution acidic (see Claim 1). A specific example of the water-poorly soluble organic acid compound is ferulic acid (see Claim 3), and the surface-treated powder pigment is disclosed to be used in makeup cosmetics and the like (see Paragraph 0001). However, even in this case, it is difficult to incorporate ferulic acid into cosmetics at high concentrations, and the need for a surface treatment step for the pigment also results in a significant economic burden. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2003-055182 [Patent Document 2] Japanese Patent Publication No. 2018-162400 [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention was completed based on the aforementioned background technology, and its purpose is to provide a sunscreen cosmetic that uses naturally derived, highly safe raw materials, is highly safe and has excellent UV protection effects, and suppresses the coloring that is a weakness when using ferulates, and a method for efficiently producing said sunscreen cosmetic. [Means for solving the problem]

[0008] The inventors of the present invention conducted diligent research to solve these problems and discovered that by dispersing ferulic acid as fine particles having a specific particle size range in an oil phase, a sunscreen cosmetic with excellent safety, minimal coloration, and superior UV protection can be obtained, and that this sunscreen cosmetic can be efficiently manufactured by wet grinding ferulic acid in the presence of an oil. Based on these findings, the present invention was completed.

[0009] In other words, the present invention relates to, for example, the following inventions. [1] A sunscreen cosmetic comprising ferulic acid (A) as fine particles in the oil phase, wherein the median diameter (D50) of the ferulic acid particles is 0.01 to 10 μm, and the content of the ferulic acid particle (A) component is 1 to 30% by mass of the total cosmetic composition. [2] The sunscreen cosmetic according to [1] further contains 0.01 to 3% by mass of γ-oryzanol (B) relative to the total cosmetic composition. [3] Sunscreen cosmetics as described in [1] or [2], which do not contain synthetically derived organic UV absorbers. [4] The sunscreen cosmetic described in [2], wherein γ-oryzanol (B) is supplied by a γ-oryzanol source. [5] The sunscreen cosmetic according to [1] or [2], wherein the cosmetic is an oil-in-water emulsion cosmetic, a water-in-oil emulsion cosmetic, or an oily cosmetic. [6] A method for producing a sunscreen cosmetic according to [1], comprising wet grinding ferulic acid (A) in the presence of an oil to prepare a fine dispersion of ferulic acid (A), and then mixing the obtained dispersion with other components that form an oil phase. [7] The method for producing a sunscreen cosmetic according to [6], wherein the wet grinding is carried out under conditions in which the mass ratio of ferulic acid (A) to the oil (ferulic acid:oil) is 2:8 to 8:2. [Effects of the Invention]

[0010] The sunscreen cosmetic of the present invention can contain a high concentration of naturally derived, highly safe ultraviolet absorbers, and therefore provides excellent UV protection without the need for synthetically derived ultraviolet absorbers, is highly safe, and has minimal coloration. [Modes for carrying out the invention]

[0011] The sunscreen cosmetic composition of the present invention contains ferulic acid (hereinafter sometimes referred to as component (A)) as an essential component. (ferulic acid) Component (A) of this invention, ferulic acid, is an intermediate in the biosynthesis pathway of lignin, a major component of plant cell walls, and is present in all plants. Its chemical name is 4-hydroxy-3-methoxycinnamic acid, and it exists in cis and trans isomers, but naturally occurring ferulic acid is almost entirely the trans isomer. In Japan, it is industrially produced by hydrolyzing γ-oryzanol and its ferulic acid ester contained in rice bran, and can be obtained commercially from companies such as Tsukuno Rice Fine Chemicals Co., Ltd. and Oryza Oil & Fat Chemical Co., Ltd.

[0012] In this invention, ferulic acid must be present in the form of fine particles in the oil phase of the sunscreen cosmetic. The median diameter (D50) of these particles is 0.01 to 10 μm, preferably 0.1 to 5 μm, and more preferably 0.2 to 3 μm. If the median diameter of the particles is excessively large, the UV protection effect will decrease, and obtaining a median diameter of less than 0.01 μm requires a great deal of energy in the atomization process, which is not economical.

[0013] In this invention, "median diameter" refers to the cumulative 50% diameter (D50) of the volume-based particle size distribution obtained by a particle size distribution analyzer. The median diameter can be measured using a laser diffraction / scattering particle size distribution analyzer (LA-950, Horiba, Ltd.) by dispersing ferulic acid particles in an oil that forms an oil phase, diluting the sample with the oil, and ultrasonically dispersing it for 5 minutes at 28 kHz using a Honda W-113 ultrasonic cleaner.

[0014] In the present invention, the method for grinding ferulic acid into such fine particles is not particularly limited, and either a dry method or a wet method can be used. Examples of grinding equipment that can be used include hammer mills, pin mills, ball mills, roll mills, jet mills, dry media mills, wet media mills, homogenizers, high-pressure homogenizers, kneaders, planetary mixers, extruders, and the like.

[0015] The method for dispersing ferulic acid fine particles in the oil phase of a cosmetic is not particularly limited, but in order to avoid re-aggregation of the ferulic acid fine particles when dispersing them in the oil phase, it is preferable to first disperse the ferulic acid in the oil by wet grinding, and then mix the dispersion with other components for forming the oil phase of the cosmetic. As for wet grinding equipment, wet media mills such as roll mills and bead mills, high-pressure homogenizers, kneaders, planetary mixers, extruders, etc., can be used. Among these, kneaders such as roll mills, kneaders, planetary mixers, and extruders can be preferably used because they can grind the dispersion at a high concentration of ferulic acid. Among these, it is preferable to use a roll mill due to its high grinding capacity and ease of equipment cleaning. A specific example of a roll mill is the three-roll mill EXAKT120EH-250 manufactured by Nagase Screen Printing Laboratory Co., Ltd.

[0016] As the oil agent used in wet grinding, there is no particular limitation as long as it is an oil agent that does not dissolve ferulic acid, and the same oil agent as that used for the oil phase of cosmetics can be used. When wet grinding ferulic acid using a kneader such as a three-roll mill to prepare a dispersion, the mass ratio of ferulic acid to the oil agent (ferulic acid: oil agent) is preferably 2:8 to 8:2, more preferably 4:6 to 7:3. When the mass ratio of ferulic acid to the oil agent is small, it is difficult to obtain fine particles, and when this mass ratio is too large, the oil agent does not become the continuous phase and it becomes difficult to obtain a dispersion.

[0017] The sunscreen cosmetic of the present invention contains ferulic acid as component (A) in an amount of 1 to 30% by mass based on the total amount of the cosmetic. More preferably, it is 2 to 20% by mass, and particularly preferably, it is 3 to 10% by mass. When the content of ferulic acid is excessively low, a high ultraviolet ray protection effect cannot be obtained, and when it is excessively high, there is concern about irritation to the skin and the like.

[0018] The sunscreen cosmetic of the present invention may contain γ-oryzanol (hereinafter sometimes referred to as component (B)) in addition to component (A).

[0019] <000,0096>γ-oryzanol is a kind of polyphenol abundant in rice germ and rice bran, and is a naturally-derived substance contained in rice oil produced by pressing rice germ and rice bran. In Japan, it is produced by separating, extracting and purifying it during the process of producing rice oil by pressing rice germ and rice bran. It is known that γ-oryzanol is not a single compound but is composed of about 10 kinds of analogs, and each analog is an ester of ferulic acid and an unsaturated triterpene alcohol or a plant sterol. γ-oryzanol is insoluble in water and can be used by dissolving it in vegetable oil or the like by heating. γ-oryzanol derived from rice bran is commercially available from Kano Rice Fine Chemicals Co., Ltd., Oryza Oil & Fat Chemical Co., Ltd. and the like.

[0020] γ-oryzanol may be used after being isolated in advance, but cosmetic raw materials containing γ-oryzanol can also be used as a source of γ-oryzanol. The amount of γ-oryzanol blended is preferably 0.01 to 3% by mass of the total cosmetic composition. Even when cosmetic raw materials containing γ-oryzanol are used as a source of γ-oryzanol, it is preferable that the amount of γ-oryzanol blended is 0.01 to 3% by mass of the total cosmetic composition. The inclusion of γ-oryzanol further enhances the sun protection effect.

[0021] Dissolving isolated γ-oryzanol in cosmetic oils requires heating. γ-oryzanol is susceptible to degradation when heated. To prevent such problems, it is preferable to use a γ-oryzanol source that can be mixed with oils without heating. Specific examples of γ-oryzanol sources include rice bran oil and rice germ oil, and it is particularly preferable to use a vegetable oil containing 1% by mass or more of γ-oryzanol. Examples of commercially available such vegetable oils include Koken's rice-pressed oil (cosmetic labeling name: rice bran oil) and Tsukuno Rice Fine Chemicals' PRO-15 (cosmetic labeling name: rice germ oil).

[0022] The sunscreen cosmetic composition of the present invention, regardless of its dosage form, contains an oil phase in which component (A) is dispersed. Specific examples of the oily agent that forms the oil phase (hereinafter sometimes referred to as component (C)) include, for example, naturally derived oils and waxes such as rice bran oil, rice germ oil, soybean oil, macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, hydrogenated coconut oil, hydrogenated oil, Japanese wax, hydrogenated castor oil, beeswax, candelilla wax, carnauba wax, privet wax, lanolin, reduced lanolin, hard lanolin, jojoba wax, etc. Hydrocarbons such as liquid paraffin, squalane, polybutene, isoparaffin, ozokerite, paraffin, ceresin, petrolatum, and microcrystalline wax; higher fatty acids such as oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and undecylenic acid; and higher alcohols such as cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, octyldodecanol, myristyl alcohol, and cetostearyl alcohol. Cetyl isooctanoate, isopropyl myristate, hexyldecyl isostearate, diisopropyl adipate, di-2-ethylhexyl sebacate, cetyl lactate, diisostearyl malate, ethylene glycol di-2-ethylhexanoate, neopentyl glycol dicaprate, glycerin di-2-heptylundecanoate, triethylhexanoin, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, tetra-2-ethylhexane Examples of oils include synthetic ester oils such as pentane erythritol acid; linear polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and diphenylpolysiloxane; cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane; silicone oils such as amino-modified polysiloxanes, polyether-modified polysiloxanes, alkyl-modified polysiloxanes, and fluorine-modified polysiloxanes. Among these, naturally derived oils and / or waxes are preferred from a safety standpoint.The content of naturally derived oils and / or waxes is preferably 70% by mass of the oil, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0023] In the sunscreen cosmetic composition of the present invention, the oil phase consists of a base oil (C), ferulic acid (A), and optionally used oil-soluble components and oil-dispersing components. Examples of oil-soluble components include oil-soluble polyphenols, oil-soluble vitamins, oil-soluble plant and animal extracts, oil-soluble skin active ingredients, oil-soluble surfactants, oil-soluble UV absorbers, oil-soluble antioxidants, and oil-soluble film-forming agents.

[0024] Examples of oil-soluble components include oil-soluble UV absorbers such as benzoic acid-based UV absorbers, anthranilic acid-based UV absorbers, salicylic acid-based UV absorbers, cinnamic acid-based UV absorbers, benzophenone-based UV absorbers, and triazine-based UV absorbers. Specific examples of these include diethylamino hydroxybenzoyl hexyl benzoate, ethylhexyl methoxycinnamate, bis-ethylhexyloxyphenol methoxyphenyl triazine, and t-butyl methoxydibenzoylmethane. However, from a safety standpoint, the sunscreen cosmetic of the present invention preferably does not contain these synthetic UV absorbers, or if they are included, the amount of synthetic UV absorbers, including water-soluble UV absorbers, is preferably 1% by mass or less of the total cosmetic composition.

[0025] Furthermore, examples of oil-dispersible components include poorly soluble polyphenols, skin-beneficial ingredients such as vitamins, and powders. Examples of powders include extender pigments, coloring pigments, fine-particle metal oxides with UV-blocking effects, and inorganic thickeners such as fuzzy silica and montmorillonite. Powders can also be used after hydrophobic or lipophilic surface treatment. In the present invention, regardless of whether or not surface treatment is performed, powders dispersed in the oil phase during cosmetic preparation are considered components of the oil phase.

[0026] The sunscreen cosmetic of the present invention can be formulated in the following ways according to conventional methods, such as an oil-in-water emulsion cosmetic, a water-in-oil emulsion cosmetic, an oily cosmetic, a two-layer cosmetic in which the aqueous and oil phases are separated, or an aerosol cosmetic. Each formulation will be described in detail below.

[0027] (Oil-in-water emulsion cosmetic) Oil-in-water emulsion cosmetics consist of an aqueous phase and an oil phase. The oil phase content is preferably 2 to 70% by mass, more preferably 3 to 60% by mass, and particularly preferably 5 to 50% by mass, relative to the total cosmetic composition. If the oil phase content is too low, it is difficult to incorporate a large amount of component (A), which tends to reduce the UV protection effect. Conversely, if the oil phase content is too high, it tends to result in a sticky feeling. The aqueous phase content is preferably 30 to 98% by mass, more preferably 40 to 97% by mass, and particularly preferably 50 to 95% by mass, relative to the total cosmetic composition.

[0028] The aqueous phase that forms the continuous phase consists of water (purified water, hot spring water, deep-sea water, etc.) and water-soluble and water-dispersible components used as needed.

[0029] Examples of water-soluble components include lower alcohols such as ethanol, polyhydric alcohols, hydrophilic surfactants, water-soluble polymers, water-soluble plant extracts, water-soluble vitamins, water-soluble UV absorbers, antibacterial agents, antioxidants, and the like.

[0030] Specific examples of water-soluble UV absorbers include ferulate salts, phenylbenzimidazole sulfonic acid and its salts, terephthalylidene dicamphor sulfonic acid and its salts, etc. However, from a safety standpoint, it is preferable that the product does not contain synthetic UV absorbers other than ferulate salts.

[0031] Specific examples of surfactants include anionic surfactants, cationic surfactants, hydrophilic nonionic surfactants, and amphoteric surfactants. In the sunscreen cosmetic composition of the present invention, from the viewpoint of safety, the surfactant content is preferably 5% by mass or less, more preferably 2% by mass or less, relative to the total cosmetic composition. Most preferably, it is not contained at all.

[0032] Specific examples of water-soluble polymers include polysaccharides such as hyaluronic acid and its salts, xanthan gum, chondroitin sulfate and its salts, dextrin, pectin, gellan gum, carrageenan, and pullulan; acrylic acid polymers such as carbomers, alkyl acrylate / (meth)acrylate copolymers, acrylic acid, polyacrylamide, copolymers of acrylamide and acrylic acid, acrylate salts, or copolymers obtained by copolymerizing hydroxyalkyl acrylate with acryloyldimethyl taurate salt; cellulose polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose; hydrophobic modified polyether urethanes; and alginic acid polymers such as alginic acid and its salts.

[0033] By including a water-soluble polymer, a stable oil-in-water emulsion cosmetic can be obtained without using a surfactant, or with the use of a small amount of surfactant. Specific examples of water-soluble polymers suitable for stabilizing oil-in-water emulsions include acrylic acid / (meth)acrylate alkyl copolymers, acrylate salts, copolymers obtained by copolymerizing hydroxyalkyl acrylate with acryloyldimethyl taurate salt, hydrophobic modified polyether urethanes, and specific examples of these include (Acretz / alkyl (C10-30) acrylate crosspolymer, (sodium acrylate / sodium acryloyldimethyl taurate) copolymer, (hydroxyethyl acrylate / sodium acryloyldimethyl taurate) copolymer, PEG-240 / decyltetradeceth-20 / HDI copolymer, polyurethane-59, and the like.

[0034] (Water-in-oil emulsion cosmetic) Water-in-oil emulsion cosmetics consist of an aqueous phase and an oil phase that forms a continuous phase. The oil phase content is preferably 20-80% by mass, more preferably 30-70% by mass, and particularly preferably 40-60% by mass, relative to the total cosmetic composition. If the oil phase content is too low, it is difficult to incorporate a large amount of component (A), which tends to reduce the UV protection effect. Conversely, if the oil phase content is too high, it tends to result in a sticky feeling. The aqueous phase content is preferably 20-80% by mass, more preferably 30-70% by mass, and particularly preferably 40-60% by mass, relative to the total cosmetic composition.

[0035] The components of the aqueous and oil phases used are the same as those for oil-in-water emulsion cosmetics. Examples of suitable surfactants for maintaining the stability of the water-in-oil emulsion include ethylene oxide-additive nonionic surfactants, polyglycerin fatty acid esters, pentaerythritol fatty acid esters, dipentaerythritol fatty acid esters, and silicone-based surfactants. Among these, from the viewpoint of safety, polyglycerin fatty acid esters, pentaerythritol fatty acid esters, and dipentaerythritol fatty acid esters, which are composed of naturally derived ingredients, are preferably used.

[0036] (Oil-based cosmetics) Oily cosmetics consist solely of an oil phase. The oil phase may be formed only from a base oil and component (A), but it is preferable to also contain one or more selected from solid oils and oily gelling agents. By including solid oils and / or oily gelling agents, the sedimentation and separation of component (A) can be prevented, and the formulation can be maintained stably.

[0037] Solid oil is an oil that is solid at room temperature (25°C), with a melting point of 50 to 120°C, preferably 55 to 105°C, and more preferably 60 to 100°C. The melting point of solid oil can be measured by the second melting point measurement method, which is a general test method of the Quasi-Drug Raw Material Standards.

[0038] Examples of solid oils include polyethylene wax, Fischer-Tropsch wax, microcrystalline wax, Japanese wax, carnauba wax, candelilla wax, rice wax, beeswax, hydrogenated jojoba oil, behenyl behenate, hydrogenated castor oil, hydrogenated oils, higher alcohols, and silicone waxes.

[0039] Examples of oily gelling agents include amino acid derivatives such as N-lauroyl-L-glutamic acid and α,γ-di-n-butylamine; dextrin fatty acid esters such as dextrin palmitate, dextrin stearate, and dextrin 2-ethylhexanoate palmitate; sucrose fatty acid esters such as sucrose palmitate and sucrose stearate; benzylidene derivatives of sorbitol such as monobenzylidene sorbitol and dibenzylidene sorbitol; and organically modified clay minerals such as dimethylbenzylddecylammonium montmorillonite clay and dimethyldioctadecylammonium montmorillonite clay.

[0040] Oil-based cosmetics can be in liquid, paste, solid, or solid stick form.

[0041] The form of the sunscreen cosmetic of the present invention is not particularly limited, and a wide range of conventional cosmetic forms can be adopted. Specific examples of forms include, for example, lotion (liquid), gel, emulsion, suspension, cream, ointment, aerosol, mist, solid, solid stick, etc.

[0042] Furthermore, there are no particular restrictions on the types of sunscreen cosmetics, as long as they are applied to the skin or hair. Specific examples include base makeup cosmetics such as foundation and makeup base; basic cosmetics such as lotions, emulsions, and creams; and sunscreen cosmetics for hair.

[0043] The sunscreen cosmetic according to the present invention can be manufactured by conventional methods, but it is preferable to first prepare a dispersion containing ferulic acid fine particles by a wet pulverization method in which ferulic acid (A) is pulverized together with an oil, and then mix the obtained dispersion with other components that form an oil phase to form an oil phase in which ferulic acid fine particles are dispersed. By using such a manufacturing method, a sunscreen cosmetic with excellent sun protection effect, feel, and usability can be efficiently produced. [Examples]

[0044] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, the amounts of ingredients in the formulations described below are in mass percent of the total amount.

[0045] The evaluation method for sunscreen cosmetics in the following examples and comparative examples is as follows. (How easily it blends into the skin) Regarding how easily the product blends into the skin, 10 evaluators applied each sample to their faces and conducted a four-point sensory evaluation based on the scoring criteria (scores) described below.

[0046] (Score) 5 points: Excellent. 4 points: Excellent. 3 points: Average. 2 points: Inferior. 1 point: Very poor. (Evaluation Criteria) A: Average score of 4.0 or higher B: Average score of 3.5 or higher but less than 4.0 C: Average score between 2.5 and 3.5 points D: Average score less than 2.5 points

[0047] (Sun protection effect) The sunburn prevention effect was measured as the SPF value (in vitro) using the SPF Analyzer UV-1000S manufactured by Labshere. As the sample application plate, SPFMASTER-PA01 manufactured by Shiseido Medical and Chemical Technology Co., Ltd. was used, and 2 mg / cm 2 of the sample was applied to the plate for measurement.

[0048] (Viscosity) After preparing the cosmetic, it was left standing at room temperature (25 °C) overnight, and the viscosity at 25 °C was measured the next day using a B-type viscometer (TVB-10M, manufactured by Toki Sangyo Co., Ltd.).

[0049] (Whiteness) The sample was packed into a cell, and the values of L * , a * , and b * were obtained, and the whiteness was calculated by the following formula. Whiteness = 100 - [(100 - L * ) 2 + (a *2 + b *2 )] 0.5

[0050] Examples 1 to 4 (Water-in-oil type sunscreen cosmetic) Sunscreen cosmetics with the formulations shown in Table 1 were prepared according to the following manufacturing procedure and evaluated by the above method. The results are shown in Table 1. (Manufacturing procedure) (1) Ferulic acid (manufactured by Tsukino Food Industry Co., Ltd.) having a particle size (D50) of 4.0 μm and rice bran oil (γ-oryzanol content 1.5%) were supplied to a three-roll mill at a mass ratio of 1:0.74 and kneaded to wet-mill ferulic acid. When a part of the kneaded sample was diluted with rice bran oil and measured using a laser diffraction / scattering particle size distribution measuring device, D50 was 1.1 μm. (2) The components described in the column of Phase A and the components described in the column of Phase B were mixed using a propeller (three-one motor). (3) After uniformly mixing the components listed in the C phase column at room temperature (25°C), the mixture obtained in (2) above was added to the resulting mixture in small amounts and emulsified to obtain an oil-in-water emulsion cosmetic.

[0051] Example 5 (Oil-in-water type sunscreen cosmetic) An oil-in-water emulsion cosmetic was obtained in the same manner as in the manufacturing procedures (2) and (3) of Example 1, except that ferulic acid with a particle size (D50: 4.0 μm) was used as is without pulverization. The obtained cosmetic was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0052] (Oil-in-water type sunscreen cosmetic) Sunscreen cosmetics with the formulations shown in Table 1 were prepared according to the manufacturing procedure described below and evaluated using the method described above. The results are shown in Table 1. (1) The ferulic acid listed in the C phase column of Table 1 was neutralized using an equivalent amount of sodium hydroxide. In all of Comparative Examples 1 to 3, the ferulic acid did not dissolve completely. (2) The components other than those listed in the C phase column were uniformly mixed, and the resulting mixture was mixed with the reactants obtained in the neutralization reaction described in (1) above. (3) A small amount of the rice bran oil described in the B phase column was added to the mixture obtained in (2) above, and an oil-in-water emulsion cosmetic was obtained by emulsification.

[0053] [Table 1]

[0054] The results from Examples 1-3 show that a higher SPF value can be obtained with increasing ferulic acid content. The cosmetics in Examples 4 and 5 also have high SPF values, but a comparison of Examples 3 and 5 shows that ferulic acid with smaller particle size exhibits a better SPF value, and a comparison of Examples 3 and 4 shows that using a vegetable oil with a high γ-oryzanol content as the oilant results in an even higher SPF value.

[0055] The sunscreen cosmetics of Examples 1-5 all exhibited excellent usability, such as good absorption into the skin, showed a viscosity within a certain range, and had high whiteness. In contrast, the cosmetics of Comparative Examples 1-3, in which ferulic acid was neutralized and incorporated into the aqueous phase, had extremely low viscosity and poor absorption into the skin, despite using the water-soluble thickener ingredient 8. Furthermore, the coloration became significantly more pronounced with increasing ferulic acid content, resulting in an inferior appearance as a cosmetic product. [Industrial applicability]

[0056] The present invention provides a sunscreen cosmetic that is excellent in safety and UV protection and has minimal coloration, as well as a method for efficiently producing such a sunscreen cosmetic.

Claims

1. A sunscreen cosmetic characterized by containing ferulic acid (A) as fine particles in the oil phase, wherein the median diameter (D50) of the ferulic acid particles is 0.01 to 10 μm, and the content of the ferulic acid particles is 1 to 30% by mass of the total cosmetic composition.

2. Furthermore, the sunscreen cosmetic according to claim 1 is characterized by containing 0.01 to 3% by mass of γ-oryzanol (B) relative to the total cosmetic composition.

3. The sunscreen cosmetic according to claim 1 or 2, characterized in that it does not contain synthetically derived organic ultraviolet absorbers.

4. The sunscreen cosmetic composition according to claim 2, wherein γ-oryzanol (B) is supplied by a γ-oryzanol source.

5. The sunscreen cosmetic according to claim 1 or 2, wherein the cosmetic is an oil-in-water emulsion cosmetic, an oil-in-oil emulsion cosmetic, or an oily cosmetic.

6. A method for producing a sunscreen cosmetic according to claim 1, characterized by wet grinding ferulic acid (A) in the presence of an oil to prepare a fine dispersion of ferulic acid (A), and then mixing the obtained dispersion with other components that form an oil phase.

7. The method for producing a sunscreen cosmetic according to claim 6, wherein the wet grinding is carried out under conditions in which the mass ratio of ferulic acid to oil (ferulic acid: oil) is 2:8 to 8:2.

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