JPH0237206B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an oil-in-water emulsion composition that has a weakly acidic pH, good stability over time, and excellent effects on the skin. BACKGROUND ART Conventionally, formulated emulsified compositions have been made as emulsifiers by combining minerals and nonionic lipophilic surfactants obtained by reaction emulsification of higher fatty acids and basic substances. At this time, since the basic substance used is strongly alkaline, the resulting emulsified composition has an alkaline pH of 8 to 10. Recently, from the perspective of dermatology, the pH of cosmetics has been
It is preferable to adjust the pH range to about 5.0 to 6.5, and therefore it is said that it is desirable for cosmetics to have a slightly acidic pH, and there is a tendency for weakly acidic cosmetics to be on the rise. Therefore, efforts have been made to lower the PH by reducing the amount of basic substances in conventional emulsified emulsion compositions, but it has been difficult to bring the pH to an acidic range. Usually, emulsified compositions with acidic pH are
This is a nonionic emulsion composition produced using an ethylene oxide adduct nonionic surfactant. However, this nonionic emulsion composition is inferior to the chemically modified emulsion composition in terms of usability such as familiarity with the skin and heavy feeling. On the other hand, the higher fatty acid salts that give the feeling of use of this formulized emulsion composition vary somewhat depending on the type of fatty acids and basic substances that make up the composition, but when the pH is made acidic, the stones are hydrolyzed. Decomposes into fatty acids and basic substances. As a result, the emulsification of the system is destroyed, resulting in poor stability and separation or lumps (solid matter).
Crystals caused by fatty acids such as luster (shininess based on needle-shaped crystals) are formed, and it is difficult to make the pH of the emulsion composition acidic. Therefore, a method of emulsifying a PH acidic nonionic emulsified composition emulsified only with the nonionic surfactant by adding a higher fatty acid that provides a feeling of use may be considered. However, even in this method, if higher fatty acids are added in an amount of 0.5% or more, which is sufficient to provide a feeling of use, higher fatty acids will precipitate. Addition of 0.5% or less is effective in systems with low viscosity such as emulsions that give a somewhat rich feel and improve blending, but it was difficult to make the emulsion particles thinner and stabilize the system. . In view of the current situation, the present inventors conducted intensive research to suppress the pH of the above-mentioned formulized emulsion composition, and as a result, they combined a certain combination of nonionic surfactants and higher fatty acid stones. We discovered that if we use an emulsifier consisting of a system in which the PH is lowered by adding an acid, we can obtain an emulsified composition that is close to the PH range of the skin, has good system stability, and is easy to use. ,
The present invention has now been completed. That is, the present invention has the general formula: RCOOM (R is an alkyl group or alkenyl group derived from a fatty acid having 11 to 30 carbon atoms, M is an alkali metal, triethanolamine, or a basic amino acid) and The system is emulsified with an emulsifier consisting of an ionic hydrophilic surfactant and a nonionic lipophilic surfactant with an HLB of less than 6, and the pH is adjusted using an organic acid and/or an inorganic acid.
This is an oil-in-water emulsion composition characterized by having a concentration of 4.0 to 7.4. Next, the configuration of the present invention will be explained in detail. The higher fatty acid salts used in the present invention are those of the general formula RCOOM where R is a higher fatty acid residue having 11 to 30 carbon atoms. Higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, isostearic acid, behenic acid, cerotic acid, lanolic acid, etc., but solid fatty acids such as stearic acid are preferably used from the viewpoint of usability. Good. In addition, as basic substances used for stone making, hydroxides such as sodium hydroxide and potassium hydroxide,
These include basic amino acids and amines typified by triethanolamine. Note that it is naturally possible to combine two or more of these higher fatty acids and basic substances, and good results can be obtained. The amount of these basic substances added is preferably 0.5 to 1 in molar ratio to the higher fatty acid. Although the higher fatty acid salt may be added as a salt from the beginning, reaction emulsification is usually used. The amount added as a higher fatty acid salt is 0.1 to 10% by weight in the emulsified composition (hereinafter, % represents % by weight). If it is less than 0.1%, it is not sufficient to emulsify the system, and if it is more than 10%, fatty acids will precipitate and the appearance of the surface will deteriorate. Addition of 0.5 to 5% is preferable in order to provide a solid feel in terms of usability and to improve the stability of the system. Next, nonionic hydrophilic surfactants with HLB6 or higher include polyoxyethylene (hereinafter abbreviated as POE) higher alcohol, POE higher fatty acid ester,
POE sorbitan fatty acid ester, POE polyhydric alcohol fatty acid ester represented by POE glycerin fatty acid ester, POE glycerin higher alcohol ether, POE hydrogenated castor oil derivative, sucrose fatty acid ester, POE sterol derivative,
Examples include POEPOP (polyoxypropylene) higher alcohol ether. In addition, nonionic lipophilic surfactants with HLB less than 6 include polyhydric alcohol fatty acid esters represented by glycerin fatty acid esters, glycerin higher alcohol ethers, polyglycerin fatty acid esters (hydrophilic ones are also known), However, in the present invention, hydrophilic polyglycerol fatty acid ester
It is classified into the above nonionic hydrophilic surfactants. ) Hydrogenated castor oil derivatives, sucrose fatty acid esters, sorbitan fatty acid esters, sterol derivatives, and the like. The amount of these nonionic surfactants added is based on the weight ratio of higher fatty acid salts.
It is preferably about 0.3 to 2, and a stable emulsified composition can be obtained even if the pH is made acidic. Here, there are various calculation methods for the HLB (lipophilicity and hydrophilicity balance) of a nonionic surfactant, and the HLB value obtained is calculated differently depending on each method.
The HLB value defined in this invention is the Kawakami formula HLB
Based on calculation method. In the present invention, a nonionic hydrophilic surfactant with an HLB of 6 or more calculated by the above method and a nonionic lipophilic surfactant with an HLB of less than 6 are combined in an oil-in-water emulsion composition system. It is adjusted to the optimum HLB for the system required depending on the amount and type of oil, but it is of course possible to use it alone by adjusting the HLB of added ethylene oxide, etc. In the present invention, organic acids added as PH regulators include oxyacids, lower carboxylic acids, and acidic amino acids. Examples of oxyacids include lactic acid, malic acid, tartaric acid, citric acid, etc., and oxyacids with relatively low molecular weights such as these examples are preferable. Among the lower carboxylic acids, dibasic acids are preferred, such as oxalic acid, malonic acid, and succinic acid. Further, examples of acidic amino acids include glutamic acid, aspartic acid, urocanic acid, and the like. Examples of inorganic acids include hydrochloric acid, carbonic acid, phosphoric acid, and silicic acid. Any other acid used in cosmetics can be used, and these can be used alone or in combination, and the pH of the emulsified composition system is 4.0 to 7.4.
It is added in an amount of Further, aqueous components added to the emulsified composition include lower alcohols, polyhydric alcohols such as propylene glycol, glycerin, and polyethylene glycol, and moisturizing agents such as sodium pyrrolidone carboxylate and amino acids, and oil-based components include, for example, liquid paraffin. , hydrocarbons such as vaseline, paraffin wax, and squalane, beeswax, lanolin, jojoba oil, esters such as synthetic oils of higher alcohols and fatty acids, alcohols such as higher alcohols and lanolin alcohol, olive oil, and toning oil, etc. These include triglycerides. Next, the effects of the present invention will be described. Table 1 shows the emulsified composition according to the present invention, Comparative Examples 1 and 2, which are conventional emulsified emulsified compositions whose pH was adjusted by adding acid, and Comparative Example 3, which is a nonionic emulsified composition. This is a comparison of physical properties such as PH, emulsified particles, and stability for those to which fatty acids have been added. The stability was compared after being left at 40°C for 7 days and at 0°C for 1 month.

【table】

[Table] Stability evaluation ○ Good △ Fairly bad
× Bad × × Very Bad As is clear from Table 1, the emulsion composition according to the present invention had good stability and fine emulsion particles. Next, examples of the present invention will be shown. Example 1 Cream % Behenic acid 4 Setanol 2 Beeswax 2 Vaseline 2 Squalane 40 Propylene glycol monostearate 1 POE (5 mol) Glycerin monostearate
1 POE (60 mol) hydrogenated castor oil derivative 1 Fragrance Appropriate amount Paraoxybenzoic acid methyl ester 0.2 Tocopherol 0.01 Glycerin 10 Potassium hydroxide 0.2 Ion exchange water 34.79 Hydrochloric acid (1N) 1.8 Production method Heat and dissolve ~ at 70-75°C. Especially~
is heated and dissolved at 70 to 75°C, and while stirring, the above-mentioned ~ is added to react and emulsify. Next, by adding and adjusting the pH, and processing with an emulsifier, an oil-in-water cream with thin and uniform emulsified particles is obtained. This emulsified composition has a pH of 5.6 and is an oil-based nutritional cream with excellent usability. Examples 2 Mulmules 1 Squid % Stearantic acid 1 isostearline acid 1 sethanol 0.5 stearyl alcoholic 0.5 Vaselin 2 Squalin mono -ohlate 1 Glycerin monster lil aetel 1 fragrance isopropyl pill methylhenol 0.1 ^k vitamin E acetate 0.05 Propiragriicol 5 trewetet Noolamine 1 PK Esther F160 (Sucrose fatty acid ester manufactured by Daiichi Kogyo Seiyaku) 1 Ion-exchanged water 75.45 Carboxyvinyl polymer 0.1 Citric acid 0.3 Manufacturing method Follow the manufacturing method in Example 1. This emulsion composition is a stable emulsion with a pH of 7.2. Example 3 Foundation % Stearic acid 1 Dimer acid 1 Oleyl alcohol 0.5 Liquid paraffin 10 Sorbitan sesquiolate 1 POE (10 mol) behenyl alcohol ether
1.5 Fragrance Appropriate amount Paraoxybenzoic acid butyl ester 0.1 Butylated hydroxytoluene 0.001 Propylene glycol 5 Sodium hydroxide 0.05 L-arginine 0.5 Xanthan gum 0.05 Montmorillonite 0.5 Ion exchange water 60.97 Inorganic pigments (titanium oxide, talc, kaolin,
Iron oxide, etc.) 15 Sodium hexametaphosphate 0.03 Hydrochloric acid (1N) 2.8 Manufacturing method Dissolve ~ by heating and adjust to 70-75℃. On the other hand, ~ is similarly heated and dissolved at 70 to 75°C, and the pigment is uniformly dispersed and mixed. The heat-dissolved ~ above is added to this to react and emulsify. After that, the pH is adjusted by adding and treated with an emulsifying machine to obtain a uniform emulsified foundation with small emulsified particles. The pH of this emulsified composition is 6.8.

Claims (1)

[Claims] 1. A higher fatty acid represented by the general formula: RCOOH (R represents an alkyl group or alkenyl group having 11 to 30 carbon atoms), MOH (M is an alkali metal), triethanolamine, and a base. consisting of at least one basic substance such as amino acids, a nonionic hydrophilic surfactant with an HLB of 6 or more, a nonionic oil-soluble surfactant with an HLB of less than 6, and an organic acid and/or an inorganic acid. An oil-in-water emulsified skin topical composition characterized by: 2 Higher fatty acids represented by the general formula: RCOOH (R represents an alkyl group or an alkenyl group having 11 to 30 carbon atoms) include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, isostearic acid, and behenin. The oil-in-water emulsified skin external composition according to claim 1, which is selected from the group of acids and lanolinic acids. 3 Nonionic hydrophilic surfactant topical preparation with HLB6 or higher, polyoxyethylene higher alcohol ether, polyoxyethylene glycerin monofatty acid ester, polyoxyethylene hydrogenated castor oil derivative, sucrose fatty acid ester, and polyoxyethylene sterol derivative group The oil-in-water emulsified skin external composition according to claim 1, which is selected from the following. 4 Nonionic lipophilic surfactants with HLB of less than 6 include glycerin monofatty acid ester, propylene glycol monofatty acid ester, glycerin monohigher alcohol ether, hydrogenated castor oil derivative,
The oil-in-water emulsified skin external composition according to claim 1, which is selected from the group of sucrose fatty acid esters and sterol derivatives. 5. The water according to claim 1, wherein the organic acid is one or more of lactic acid, malic acid, tartaric acid, citric acid, oxalic acid, malonic acid, succinic acid, glutamic acid, aspartic acid, or urocanic acid. Oil-type emulsified skin composition for external use. 6. The oil-in-water emulsion skin external composition according to claim 1, wherein the inorganic acid is one or more of hydrochloric acid, carbonic acid, phosphoric acid, or silicic acid.