Aqueous dispersion composition

Abstract

To obtain a dispersion in which carbon black or fine plant-charcoal powder is dispersed in water, the dispersion being easy to handle since water serves as the dispersion medium, and being suitably utilizable when employed in cosmetics or the like, and when carbon black or fine plant-charcoal powder is incorporated into a cosmetic.SOLUTION: Provided is a dispersion composition in which carbon black or fine plant-charcoal powder is uniformly dispersed in water, wherein, by using a dialkyl sulfosuccinate as a dispersant, carbon black or fine plant-charcoal powder can be stably dispersed in water.

Description

[Technical Field]

[0001] The present invention relates to an aqueous dispersion composition using carbon black or vegetable charcoal fine particles that can be used as a raw material for cosmetics. [Background technology]

[0002] Carbon black is usually a fine particle with an average particle size of submicrons or less, and therefore has the property of easily agglomerating. Therefore, in order to use carbon black in an aggregated state as a black pigment in cosmetics, some ingenuity is required, such as dispersing it in water to form an aqueous dispersion composition. However, because the surface activity of carbon black particles is low, it is difficult to obtain a good aqueous dispersion composition by simply mixing carbon black in its original state with water.

[0003] Conventional methods for improving the dispersibility of carbon black in water include, for example, a technique of subjecting carbon black to an oxidation treatment to introduce hydrophilic functional groups onto the surface of the carbon black (see, for example, Patent Document 1), and a technique of using a surfactant in combination when dispersing carbon black in water (see, for example, Patent Documents 2 and 3).

[0004] Furthermore, Patent Documents 4, 5, 6 and 7 disclose examples in which plant charcoal such as medicinal charcoal is used as a black pigment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-3498 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-53158 [Patent Document 3] Japanese Patent Application Publication No. 2020-70259 [Patent Document 4] Japanese Patent Application Laid-Open No. 2001-48747 [Patent Document 5] Japanese Patent Application Laid-Open No. 2007-126583 [Patent Document 6] Japanese Patent Application Laid-Open No. 2006-8577 [Patent Document 7] Japanese Patent Application Laid-Open No. 2006-22008 Summary of the Invention

[0006] However, the carbon black disclosed in Patent Document 1 is used as a raw material for aqueous pigment inks, and its hydrophilicity is improved by introducing hydroxyl groups or carboxyl groups onto its surface. Carbon black with such hydrophilic groups introduced is classified as self-dispersible carbon black, and while it exhibits good dispersibility in water by itself, it suffers from the problem of poor water resistance. For this reason, although self-dispersible carbon black can be used as a raw material for aqueous pigment inks such as those disclosed in Patent Document 1, it is not suitable for applications that are constantly exposed to a humid environment, such as cosmetics.

[0007] The carbon black disclosed in Patent Document 2 is used as a black pigment in cosmetics, and a nonionic surfactant is used as a dispersant when dispersing the carbon black in water. However, the use of such surfactants can sometimes cause various problems. For example, depending on the combination of surfactant and solvent, carbon black sedimentation may occur due to solvent shock. Furthermore, if the use of a surfactant makes the carbon black excessively hydrophilic, the film formation of the cosmetic on the skin may become weak, resulting in rapid makeup removal.

[0008] The aqueous liquid cosmetic preparation disclosed in Patent Document 3 is an aqueous composition containing carbon black prepared using diethylhexyl sodium sulfosuccinate, and also contains a water-soluble dispersant such as a water-soluble polymer and a film-forming polymer emulsion as other ingredients. However, the use of a water-soluble polymer or a film-forming polymer emulsion increases the viscosity of the aqueous composition, making it difficult to incorporate a large amount of carbon black.

[0009] The medicinal charcoal disclosed in Patent Documents 4, 5, 6, and 7 has safety concerns due to its too small particle size. In addition, the concentration of vegetable charcoal in the dispersion is low, which limits its use as a substitute for black iron oxide or carbon black. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aqueous dispersion composition that has high dispersibility of carbon black or vegetable charcoal fine particles and also has high water resistance during use. [Means for solving the problem]

[0010] As a result of intensive research conducted by the present inventors in order to achieve the above-mentioned object, they discovered that the use of a dialkyl sulfosuccinate salt allows carbon black or vegetable charcoal fine particles to be stably dispersed in water, thereby completing the present invention.

[0011] That is, the aqueous dispersion composition according to the present invention is an aqueous dispersion composition containing carbon black or plant charcoal fine powder, a dialkyl sulfosuccinate, and water, and is characterized in that the content of the dialkyl sulfosuccinate is 2 to 10 mass% based on the total amount of the aqueous dispersion composition. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, specific embodiments of the aqueous dispersion composition according to the present invention and the cosmetic preparation containing the same will be described. In this specification, the range "X to Y" means "X or more, Y or less." Unless otherwise specified, the operations are carried out under the conditions of room temperature (20°C to 30°C) and a relative humidity of 45 to 55% RH. The aqueous dispersion composition of the present invention has high dispersibility of carbon black or vegetable charcoal fine particles, maintains this dispersibility over time, and is highly water resistant.

[0013] (carbon black or vegetable charcoal fine powder) The carbon black used in the aqueous dispersion composition of the present invention is used as a coloring material for eye makeup cosmetics and hair dyes, and is not particularly limited as long as it is a carbon black that is commonly used as a coloring material for black-based liquid cosmetics, and various types of carbon black can be used. Examples of the carbon black include furnace black, channel black, acetylene black, and other commercially available carbon blacks used in hair dye compositions manufactured by various methods, specifically Uniview Black LC902 (manufactured by Sensient Co., Ltd.), Midnight Black (manufactured by Geotech Co., Ltd.), and C47-2222 SunCROMA D&C Black 2 (manufactured by Sun Chemical Co., Ltd.), but are not particularly limited to these.

[0014] Generally, aqueous dispersions containing carbon black have problems such as a long dispersion time due to the strong cohesion of the carbon black, and reduced productivity and stability over time during the production of the dispersion. However, the dispersion having the blending characteristics of the present invention can solve the above problems.

[0015] The vegetable charcoal fine powder used in the aqueous dispersion composition of the present invention can be plant-derived charcoal such as binchotan, bamboo charcoal, plum charcoal, pine charcoal, birch charcoal, or maple charcoal, or activated charcoal produced from coconut husks, among others. Among these, those with a carbon content of 95% or more (with an ignition residue of 5% or less) are particularly required. Considering its intended use in cosmetics, it is desirable for the vegetable charcoal fine powder to conform to the Japanese Pharmacopoeia (medicinal charcoal) in Japan. Furthermore, considering the energy required for grinding, it is preferable to use pre-ground vegetable charcoal fine powder. Specifically, those with an average particle size of 10 μm or less are preferred, and those with an average particle size of 5 μm or less are even more preferred. Examples of vegetable charcoal fine powder include, but are not limited to, Binchotan Powder BM, Binchotan Powder BM300 (manufactured by Latest Co., Ltd.), and Bamboo Charcoal Powder 5P (manufactured by Glico Nutrition Foods Co., Ltd.).

[0016] The carbon black or vegetable charcoal fine powder content in the present invention is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. When the carbon black or vegetable charcoal fine powder content is 10% by mass or more, when the aqueous dispersion composition of the present invention is used as a raw material for cosmetics, sufficient black color development can be achieved even with a small amount of the aqueous dispersion composition blended.

[0017] (dialkyl sulfosuccinate) The dialkyl sulfosuccinate used in the aqueous dispersion composition of the present invention can be obtained, for example, by reacting an alcohol with maleic anhydride to form a diester, followed by sulfation. The alcohol used is preferably a linear or branched alcohol having 6 to 22 carbon atoms, more preferably a linear or branched alcohol having 6 to 12 carbon atoms. The alcohol may be saturated or unsaturated, but saturated alcohol is preferred. Examples of alcohols used include hexanol, octanol, decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, 2-ethylhexanol, and 2-methyldodecanol. Among these, 2-ethylhexanol, hexanol, octanol, decanol, or lauryl alcohol is preferred. Examples of salts of dialkyl sulfosuccinate include alkali metals such as sodium and potassium; lower alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; and ammonia. Among these, it is preferable to use alkali metal salts such as sodium and potassium, and more preferably sodium salts. Commercially available dialkyl sulfosuccinates can be used.

[0018] The two alkyl groups constituting the dialkyl sulfosuccinate are each preferably a linear or branched alkyl group having 6 to 22 carbon atoms, and more preferably a linear or branched alkyl group having 6 to 12 carbon atoms. Specific examples of the alkyl group include an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-decyl group, a lauryl group, a myristyl group, and a stearyl group. Specific examples of dialkyl sulfosuccinates include dihexyl sodium sulfosuccinate, di-2-ethylhexyl sodium sulfosuccinate, dilauryl sodium sulfosuccinate, etc., with di-2-ethylhexyl sodium sulfosuccinate being particularly preferred.

[0019] The content of the dialkyl sulfosuccinate in the aqueous dispersion composition of the present invention is 2 to 10% by mass, preferably 4 to 9% by mass, and the blending ratio of dialkyl sulfosuccinate to carbon black or vegetable charcoal fine powder is 1 / 15 to 2 / 3, preferably 2 / 15 to 3 / 5. When the aqueous dispersion composition of the present invention is applied to a cosmetic product in the final product form, the above ranges provide a better balance between the dispersibility of the carbon black or vegetable charcoal fine powder in water and the water resistance and strength of the film containing the carbon black or vegetable charcoal fine powder. Furthermore, the aqueous dispersion composition has an appropriate viscosity, making it easy to handle. If the content of the dialkyl sulfosuccinate is less than 2% by mass, the stability over time of the aqueous dispersion composition and the water resistance of the cosmetic product in the final product form may be poor. On the other hand, if the content of the dialkyl sulfosuccinate exceeds 10% by mass, the viscosity of the aqueous dispersion composition becomes too high, making it difficult to handle.

[0020] The aqueous dispersion composition of the present invention preferably does not contain components other than the essential components of the present invention, carbon black or vegetable charcoal fine powder, dialkyl sulfosuccinate, and water, in a proportion of more than 20% by mass in the aqueous dispersion composition, but may contain other components in a proportion of 20% by mass or less relative to the aqueous dispersion composition, more preferably 10% by mass or less, 5% by mass or less, 3% by mass or less, 1% by mass or less, or even 0% by mass, as long as the performance of the aqueous dispersion composition is not impaired. However, it is preferable not to add compounds that may impair the stability of the aqueous dispersion composition.

[0021] Examples of such components that may be added include, but are not limited to, polyhydric alcohols and preservatives. That is, dispersions composed of the above components may decay depending on the storage conditions and storage period. To prevent such decay, polyhydric alcohols and preservatives may be added. Such polyhydric alcohols and preservatives are not particularly limited. Examples of polyhydric alcohols include propylene glycol, 1,3-butylene glycol, dipropylene glycol, pentylene glycol, hexylene glycol, propanediol, and 1,2-hexanediol. Polyhydric alcohols may be used alone or in combination. Examples of preservatives include parabenzoic acid esters such as methyl parahydroxybenzoate, sodium benzoate, phenoxyethanol, and sodium dehydroacetate. Preservatives may be used alone or in combination. Each of these components may be added within a range that exhibits antiseptic properties and does not adversely affect the performance of the dispersant.

[0022] The specific amounts of the polyhydric alcohols and preservatives mentioned above can be, for example, 20% by mass or less, or 15% by mass or less, more preferably 10% by mass or less, and may be 5% by mass or less, 3% by mass or less, 1% by mass or less, or 0.5% by mass or less. Among these, polyhydric alcohols such as propylene glycol, 1,3-butylene glycol, dipropylene glycol, pentylene glycol, hexylene glycol, propanediol, and 1,2-hexanediol are particularly preferred, and at least one selected from the group consisting of 1,3-butylene glycol, dipropylene glycol, pentylene glycol, and 1,2-hexanediol is preferred. The above polyhydric alcohols are often used in cosmetics as moisturizing agents, but their antibacterial properties also make them effective as preservatives.

[0023] In addition to the above, a pH adjuster may be added to the aqueous dispersion composition of the present invention. Examples of the pH adjuster include buffers such as lactic acid-sodium lactate, citric acid-sodium citrate, and succinic acid-sodium succinate.

[0024] The dispersion method for obtaining the aqueous dispersion composition of the present invention may be any known method that can achieve uniform dispersion. Various dispersing machines such as a wet bead mill, a homomixer, a disperser, a kneader, a kneading extruder, and a roll mill can be used. However, the use of a wet bead mill is preferred because it reduces the dispersed particle size of the carbon black or plant charcoal fine powder in the aqueous dispersion composition, resulting in stronger color development when applied to cosmetics. [Example]

[0025] The present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "%" means % by mass unless otherwise specified.

[0026] An aqueous dispersion composition was prepared by dispersing carbon black or vegetable charcoal fine particles and a dialkyl sulfosuccinate in water. The resulting aqueous dispersion composition was evaluated for dispersibility and water resistance.

[0027] The raw materials for the aqueous dispersion compositions were charged into a wet bead mill (DYNO-MILL manufactured by Shinmaru Enterprises) in the formulations shown in Tables 1 and 2 below together with φ0.5 mm zirconia beads so that the filling rate of the zirconia beads was 70%, and the mixture was dispersed and mixed at a peripheral speed of 10 m / s for 1 hour to prepare the aqueous dispersion compositions of Examples 1 to 8 and Comparative Examples 1 to 4.

[0028] [Table 1]

[0029] [Table 2]

[0030] <Evaluation method: appearance (dispersion state)> The dispersion state of the aqueous dispersion compositions obtained in Examples 1 to 8 and Comparative Examples 1 to 4 was visually observed immediately after production and after 2 weeks of storage at 45°C. Uniform dispersion was evaluated as ◯, slight powder aggregation was evaluated as △, and significant powder aggregation was evaluated as ×. The results are shown in Table 3.

[0031] <Evaluation method: Water resistance> A sample of the aqueous dispersion composition was applied to the inside of the forearm, left to dry for 10 minutes, and then water was added dropwise. The condition of the applied film of the aqueous dispersion composition was then visually observed. The evaluation criteria were as follows. The results are shown in Table 3. ◯: Water was repelled and no wetting of the coating film by water was observed. Δ: Water was slightly repelled, but slight wetting of the coating film by water was observed. ×: Water was not repelled, and significant wetting of the coating film with water was observed.

[0032] [Table 3]

[0033] From the results shown in Table 3, it is clear that the aqueous dispersion composition of the present invention has a good dispersion state and water resistance, and can be suitably used in cosmetics. [Industrial Applicability]

[0034] The aqueous dispersion composition of the present invention has a good dispersion state and water resistance, and is highly industrially applicable as a raw material for cosmetics such as eye shadow, mascara, eyeliner, foundation, and blush.

Claims

[Claim 1] An aqueous dispersion composition comprising carbon black or vegetable charcoal fine powder, a dialkyl sulfosuccinate, and water, wherein the content of the dialkyl sulfosuccinate is 2 to 10 mass% based on the total amount of the aqueous dispersion composition.

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