JPS643529B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a conventional oil-in-water emulsion composition that can be produced without using a hydrophilic surfactant, and particularly to a method for producing an oil-in-water emulsion composition for cosmetics. Conventionally, oil-in-water emulsion compositions for cosmetics such as cosmetic creams have oil and aqueous phase components as main components,
It is provided by adding other powders, pigments, preservatives, fragrances, etc. This type of cosmetic cream usually contains hydrophilic surfactants,
For example, fatty acid soaps and nonionic surfactants such as polyoxyethylene alkyl ethers are used as emulsifiers, but they have the following drawbacks, and it is said that they do not necessarily provide desirable products. hard. Namely: 1. Generally highly irritating to the skin. 2. Manufacturing conditions (temperature, stirring power, cooling rate, etc.) affect the quality of the final product, making it difficult to consistently obtain products of uniform quality. In particular, physical properties such as cream hardness are strongly dependent on temperature changes. 3. Conditions tend to change over time (separation, syneresis, etc.). 4 The product may have a sticky feel, which may be sensually undesirable. The following points can be mentioned. In order to solve these problems caused by hydrophilic surfactants, various methods are being considered, such as reducing the amount used as much as possible or not using hydrophilic surfactants, but it is still difficult to obtain satisfactory results. I haven't reached it yet. The present inventor has discovered that the oil phase component containing a higher fatty acid or a higher fatty acid-containing substance and a base component containing at least a clay mineral having a specific gelling ability are mixed and strongly stirred under certain conditions. As described below, complexes have an emulsifying function that uniformly disperses oil, and by applying this function, various disadvantages that occur when the above-mentioned hydrophilic surfactants are blended can be solved. I found out. That is, the present invention comprises 5 to 60% by weight of an oil phase component containing a higher fatty acid and/or a higher fatty acid-containing substance, 40 to 90% by weight of an aqueous phase component, and one or more gels selected from montmorillonite group clay minerals, bentonite, and synthetic mica. Clay minerals with chemical ability 0.5 to 5
Oil-in-water emulsification in which the base components are mixed at a pH of 4.0 to 10.5 and then stirred vigorously in a temperature range in which the oil phase components are dissolved, followed by cooling. The present invention relates to a method for producing a composition. The present invention will be explained in detail below. The oil phase components applicable to the present invention may be ordinary ones, and include various oils and fats, waxes, hydrocarbons, esters, higher alcohols, etc., but specific examples include liquid paraffin, squalane, pristane,
- Methyl nonadecane, oleyl alcohol, olive oil, isopropyl myristate, octyldecyl myristate, petrolatum, solid paraffin,
Examples include silicone oil, lanolin, almond oil, 2-ethylhexanoic acid triglyceride, tetramethylpentadecane, and cetanol. Higher fatty acids contained in the oil phase components include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, melisic acid, oleic acid,
They are straight chain, branched, saturated, unsaturated and oxyfatty acids having 12 to 30 carbon atoms such as -oxy-stearic acid and 2-octyldodecanoic acid. Furthermore, instead of directly using higher fatty acids, a substance containing higher fatty acids may be used. Such a substance may be any substance that normally contains 1% by weight or more of the above-mentioned higher fatty acids, and includes, for example, natural substances containing free fatty acids such as beeswax. These higher fatty acids and higher fatty acid-containing substances are used singly or in combination of two or more. Further, the content of higher fatty acids in the oil phase component at this time must be 0.01% by weight or more, preferably 0.1% by weight or more. Although the upper limit is not critical, it is preferably 50% by weight or less in consideration of the characteristics (feel, safety) of the resulting emulsion composition. In addition to water, water phase components include ethyl alcohol, propyl alcohol, glycerin, propylene glycol, ethylene glycol, maltitol, diglycerin, sodium lactate, sodium pyrrolidone carboxylate, sodium chondroitin sulfate, sodium hyaluronate, etc. The ratio is 1 to 50 parts per 100 parts of water.
Can be replaced within the range of . In the present invention, since it is possible to use a large amount of ethyl alcohol, propylene glycol, etc., it is effective for preserving the system. Clay minerals with gelling ability used in the present invention include montmorillonite, beidellite, nontronite, hectorite, synthetic hectorite (trade name Laponite, Laporte Industries
In addition to montmorillonite clay minerals such as montmorillonite group clay minerals (manufactured by Limited) and other bentonites, various types of synthetic mica (trade name Daimolite, manufactured by Topy Industries, Ltd.) and Veegum (manufactured by Vanderbilt) are considered, but they are synthetic products. The synthetic hectorite is most preferably used because of its small variation in quality and strong emulsifying power. In the emulsified composition according to the present invention, in order to generate a complex in place of a surfactant, in the mixed system of the oil phase component containing the higher fatty acid and the aqueous phase component, gel is added to 100 parts of the aqueous phase component. It is necessary to use 1 to 10 parts of the clay mineral having the ability to form. If the amount is less than 1 part, the resulting emulsion will not gel, resulting in easy drainage and no stable emulsion will be formed.
If it exceeds 10 parts, gelation takes priority and uniform emulsification is difficult to occur. In order to measure the permissible amount of higher fatty acids necessary to obtain a good emulsion, the inventors varied the amounts of various higher fatty acids and various higher fatty acid-containing substances as shown in the following evaluation tests 1 and 2. After mixing 49.25% by weight of the oil phase component, 49.25% by weight of water, and 1.5% by weight of synthetic hectorite (trade name Laponite XLG), the mixture was heated to 80°C.
using an Ace homogenizer (Nippon Seiki)
The above range was obtained by stirring at 15000 rpm for 10 minutes to emulsify. Evaluation test 1 (when using stearic acid) Oil phase fixed paraffin 5.0 parts by weight Liquid paraffin 44.25-x Stearic acid x Water phase water 49.25 parts by weight Clay mineral Synthetic hectorite 1.5 parts by weight

[Table] ○: Good ×: Separation or syneresis evaluation test 2 (when using beeswax (containing about 14 wt% free fatty acids)) Oil phase solid paraffin 5.0 parts by weight Liquid paraffin 44.25−x Beeswax x aqueous phase water 49.25 parts by weight Part clay mineral Synthetic hectorite 1.5 parts by weight

[Table] ○: Good ×: Separation or syneresis Similarly, in order to determine the ratio of clay minerals with gelling ability to the aqueous phase components, the present inventors conducted higher fatty acids (as shown in the following evaluation test 3). Stearic acid) is dissolved at a ratio of 0.1%, 1%, and 10% by weight, respectively, to make the oil phase component and water phase component 1:1 (weight ratio). ) were mixed in varying amounts and emulsified by stirring at 15,000 rpm for 10 minutes at 80°C using a Youth Homogenizer (Nippon Seiki), and the above range was obtained. Evaluation test 3 (stearic acid 1% by weight) Oil phase composition Liquid paraffin 85% by weight Solid paraffin 14 Stearic acid 1 Water phase composition Water 100% by weight Clay mineral synthetic hectorite

[Table] ○: Good, △: Non-uniform emulsification, ×: Separation or syneresis The results are the same as in Table 3 when stearic acid is 0.1wt% and 10wt%. The novel method for producing an oil-in-water emulsion composition according to the present invention includes mixing the above-mentioned components under certain conditions,
This is a production method that involves strong stirring, and the order of addition of each component does not matter, but in order to obtain at least a good oil-in-water emulsion composition, higher fatty acids and higher fatty acid-containing substances should be added to the oil phase components. In addition to sufficiently dissolving the ingredients, each component should be adjusted to a pH range of 4.0 to 10.5. PH less than 4.0 or PH
If it is 10.5 or more, gelation will not occur and therefore, in any case, it will not be possible to obtain a product suitable for the purpose of the present invention. PH
The adjustment is carried out by combining various bases selected, but if necessary, it may be carried out using an appropriate amount of acid, alkali, etc. In detail, the production method of the present invention uses an oil phase component containing a higher fatty acid or a higher fatty acid-containing substance, a water phase component, and a gelling ability that are selected (or adjusted) in advance to have a pH in the range of 4.0 to 10.5. Mix each component such as clay minerals in an appropriate order, and then heat at 70℃ to 90℃.
Stir vigorously using a mixer such as a homogenizer or a homomixer at a high temperature of about 80°C, preferably around 80°C. Stir for 5 to 30 minutes at a speed of about 5,000 to 20,000 rpm, and cool or leave to cool the resulting emulsion. The present invention relates to a method for producing an oil-in-water emulsion composition. Strong stirring in this production method is necessary to finely disperse the oil phase components into the gel. Further, the temperature range is necessarily set within a range in which solid fat such as wax to be added is sufficiently dissolved. In general, synthetic hectorite (same as above), which belongs to the montmorillonite clay mineral, is widely used as a gelling agent or solizing agent in the cosmetic field. It is one of the raw materials for cosmetics. When synthetic hectorite is added to an aqueous solution and the concentration exceeds a certain level, it forms a gel in water and exhibits no fluidity. In a synthetic hectorite aqueous solution in which gel formation has already occurred, when the gel strength becomes strong, it tends to be difficult to uniformly disperse the oil even if oil is added thereto.
In the present invention, when the three components of higher fatty acid or higher fatty acid-containing substance, aqueous phase component, and synthetic hectorite are mixed and stirred, a complex that replaces the surfactant is generated during the stirring, and the synthetic hectorite and the aqueous phase are mixed and stirred. Since gel formation and emulsion formation proceed simultaneously with all components, gel strength is maintained as a result, and oil can be uniformly dispersed.
Synthetic hectorite has been used as a gelling agent in cosmetics in the past, but it can be said that there have been no examples where it has been used for the purpose of contributing to the production of emulsions. In order to demonstrate whether the oil-in-water emulsion composition obtained by the present invention does not use a surfactant and is safe without skin irritation, the oil-in-water emulsion composition for cosmetics in Example 1 described below was prepared. Using an emulsified composition and an oil-in-water emulsified composition for cosmetics manufactured by a conventional method by removing synthetic hectorite from this formulation and replacing it with various surfactants, human bodies were tested for 48 hours on 50 healthy adult males nationwide. A patch test was conducted. As a result, the latter oil-in-water emulsion composition for cosmetics corresponding to a commercially available product showed a high positive rate, whereas the former oil-in-water emulsion composition for cosmetics according to the present invention hardly showed any positive results. . In the method for producing an oil-in-water emulsion composition according to the present invention, if necessary, like a normal emulsion composition,
Amino acids, fragrances, preservatives, pigments, plasticizers, thickeners, neutralizing agents, ultraviolet absorbers, chelating agents, etc. can be used. Further, the use of surfactants within a range suitable for the purpose of the present invention is permissible. The oil-in-water emulsion composition obtained as described above, especially the oil-in-water emulsion composition for cosmetics, is safe with almost no skin irritation, and is uniform without the need for careful setting of conditions during production. It is possible to obtain a product of good quality, it is possible to preserve the system, its physical properties do not change over time, the hardness of the emulsion does not depend on temperature, and it provides a refreshing feeling of use. Specifically, creams such as hand creams, emollient creams, foundations, and chitin creams, as well as emulsified products such as emulsions and packs, range from high viscosity to low fluidity. It can be used in a wide range of applications, even viscous ones. In addition, regardless of cosmetics, ointment bases, foodstuffs, paints,
It can be used for various purposes such as shoe cream. Next, an example of the method for producing the oil-in-water emulsion composition of the present invention will be described. In addition, the numerical values in the examples represent parts by weight. Example 1

【table】

[Table] Dissolve A uniformly for about 10 minutes at around 70°C, add B prepared in advance, add C and mix, then maintain the temperature at 70°C and stir at 10,000 rpm. The resulting emulsion was stirred vigorously for 10 minutes, and the resulting emulsion was allowed to cool, and D was added to obtain the desired oil-in-water emulsion composition. Example 2

[Table] Dissolve A uniformly at around 70°C for about 10 minutes, add B prepared in advance, add C and mix, then maintain the temperature at 70°C and stir at 10,000 rpm. The resulting emulsion was stirred vigorously for 10 minutes, and the resulting emulsion was allowed to cool, and D was added to obtain the desired oil-in-water emulsion composition. Example 3

【table】

[Table] Dissolve A uniformly for about 10 minutes at around 70°C, add B prepared in advance, add C and mix, then maintain the temperature at 70°C and stir at 10,000 rpm. The resulting emulsion was stirred vigorously for 10 minutes, and the resulting emulsion was allowed to cool, and D was added to obtain the desired oil-in-water emulsion composition. Example 4

[Table] Dissolve A uniformly at around 70°C for about 10 minutes, add B prepared in advance, add C and mix, then maintain the temperature at 70°C and stir at 15000 rpm. The resulting emulsion was stirred vigorously for 10 minutes, and the resulting emulsion was allowed to cool, and D was added to obtain the desired oil-in-water emulsion composition.

Claims (1)

[Claims] 1 Oil phase component containing higher fatty acids and/or higher fatty acid-containing substances 5 to 60% by weight, water phase component 40 to 90% by weight
PH4.0 consisting of 0.5 to 5% by weight of a clay mineral having gelling ability of one or more types selected from montmorillonite group clay minerals, bentonite, and synthetic mica.
A method for producing an oil-in-water emulsion composition, which comprises mixing base components adjusted to a temperature of 10.5 to 10.5, followed by vigorous stirring in a temperature range in which the oil phase component is dissolved, and cooling.