JP5306676B2 - Sucrose fatty acid ester and emulsifier for oil-in-water emulsion composition - Google Patents

Description

  The present invention relates to a sucrose fatty acid ester having a specific ester composition, and an emulsifier for an oil-in-water emulsion composition containing the sucrose fatty acid ester.

  Sucrose fatty acid esters are nonionic surfactants in which fatty acids are ester-bonded to the hydroxyl groups of sucrose (sucrose) and are used in various fields because of their high safety. Since the above sucrose has eight hydroxyl groups in one molecule, sucrose fatty acid esters are generally produced as a mixture of esters having different degrees of esterification and are commercially available.

  Regarding such sucrose fatty acid esters, the following Patent Documents 1 to 5 propose that those containing 50% by weight or more of a diester component having a degree of esterification of 2 are used in the fields of cosmetics, pharmaceuticals, foods and the like. .

  That is, Patent Document 1 discloses an oil-in-water emulsion composition having excellent water repellency and retention on the skin by using sucrose fatty acid diester and an ionic surfactant as an emulsifier. Discloses that sucrose fatty acid diester is used as a component for forming a vesicle as a microcapsule of an active ingredient, and that leakage of the active ingredient is reduced over a long period of time.

In Patent Documents 3 and 4, a thickening gelling agent that is excellent in stability and usability and can perform good thickening gelation by using a sucrose fatty acid diester and an ionic surfactant in combination. Patent Document 5 discloses water repellency and retention on skin using sucrose fatty acid diester as a thickening gelling agent together with ionic surfactant and higher fatty acid alcohol and / or higher fatty acid. The point which obtains the oil-in-water-type emulsion composition which is excellent in is disclosed.
Japanese Patent Laid-Open No. 05-246821 JP 05-155757 A JP 05-279651 A Japanese Patent Application Laid-Open No. 07-026245 Japanese Patent Application Laid-Open No. 07-025724

  The technique disclosed in the above document requires that the diester component is 50% by weight or more based on the total sucrose fatty acid ester, but the solubility when actually dissolved in water and the moisturizing in cosmetic applications. From the viewpoint of sex, it turned out to be not necessarily the best range. For example, even if the diester component is 50% by weight or more, the sucrose fatty acid ester itself is poor in water solubility if the ester component is higher than the triester, and if the monoester component is large, the formed lamellar phase There is a problem that sufficient water cannot be retained.

  Further, intensive investigations have been made on such ester composition, and when a sucrose fatty acid ester having a specific ester composition is used as an emulsifier for an oil-in-water emulsion composition, the viscosity of the emulsion composition is specifically increased. I found that I could do it. By specifically changing the viscosity of the system, not only can the physical properties and feel when the cream is prepared be improved, but the stability in the emulsification system and the dispersion system is stabilized as the viscosity of the medium increases according to Stokes' law. Since it is known to contribute, stabilization of the system such as sedimentation suppression of solid dispersoids is expected.

  The present invention has been made on the basis of the above knowledge, and has excellent solubility when dissolved in water, that is, it easily forms a lamellar phase when dissolved in water, and has moisture retention (moisture retention). It is an object of the present invention to provide a sucrose fatty acid ester that is excellent in ability) and that can specifically increase the viscosity of an oil-in-water emulsion composition.

The emulsifier for the oil-in-water emulsion composition according to the present invention is a diester having a fatty acid having 12 to 22 carbon atoms as a constituent fatty acid, a monoester component having a degree of esterification of 5 to 14% by weight, and a degree of esterification of 2. It contains a sucrose fatty acid ester comprising 55 to 65% by weight of the component and 26 to 35% by weight of the ester component having an esterification degree of 3 or more.

  According to the present invention, by defining the ester composition of the sucrose fatty acid ester as described above, the sucrose fatty acid ester is excellent in solubility when dissolved in water, and also excellent in moisture retention (moisture retention ability). Furthermore, the viscosity of the oil-in-water emulsion composition can be specifically increased.

  Hereinafter, matters related to the implementation of the present invention will be described in detail.

  The sucrose fatty acid ester according to the present invention has a content of a monoester component having a degree of esterification of 1 (sucrose fatty acid monoester; hereinafter, sometimes simply referred to as “monoester”) of 5 to 14% by weight. The ester component having a degree of esterification of 2 (sucrose fatty acid diester; hereinafter simply referred to as “diester”) is 55 to 65% by weight, and the ester component having a degree of esterification of 3 or more A mixture of sucrose fatty acid esters in which the content of sugar fatty acid polyester (hereinafter sometimes referred to simply as “polyester”) is 26 to 35% by weight. Such an ester composition is shown in a hatched range in FIG. 1 and defines a limited range among sucrose fatty acid esters.

  The reason why the ester composition is defined in this way is as follows. That is, the solubility when dissolved in water can be improved by setting the polyester content to 35% by weight or less. Conversely, if the polyester content exceeds 35% by weight, not only will it not be completely transparent and dissolved, but even if it is evenly dispersed and swollen in water, the swollen phase of the aqueous phase and sucrose fatty acid ester over time Will be separated.

  Moreover, when the content of the monoester is 14% by weight or less, the moisture retention ability when the aqueous solution is made can be increased, and for example, the moisturizing effect when used in cosmetics can be enhanced. Moreover, the water | moisture retention capability of above-mentioned aqueous solution can be improved more notably by making content of a diester 55 weight% or more. And with these regulations, the monoester content is defined as 5% by weight or more, the diester content is defined as 65% by weight or less, and the polyester content is defined as 26 parts by weight or more. The viscosity can be increased specifically. By obtaining an emulsified liquid having a high viscosity, the stability can be enhanced, and when used as an external preparation for skin, for example, the feel to the skin can be improved.

  The polyester preferably contains a triester having a degree of esterification of 3 as a main component. Specifically, in all sucrose fatty acid esters, the triester component is 20 to 30% by weight, and the degree of esterification is It is preferable that 4 or more components are 0 to 10 weight%, More preferably, a triester component is 20 to 26 weight%, and a component with a degree of esterification of 4 or more is 3 to 9 weight%.

  As fatty acid which comprises the said sucrose fatty acid ester, C12-C22 saturated or unsaturated, linear or branched thing is mentioned, It uses 1 type or in combination of 2 or more types. Preferred is a saturated fatty acid having 14 to 20 carbon atoms, more preferred is a mixture of stearic acid and palmitic acid, and particularly preferred is stearic acid / palmitic acid = 60/40 to 90/10 (weight ratio).

  The sucrose fatty acid ester having the above ester composition can be prepared by using a known synthesis method. In general, as a method for synthesizing a sucrose fatty acid ester, a method of reacting sucrose with a fatty acid alkyl ester (for example, fatty acid methyl) in a reaction solvent such as dimethylformamide or dimethyl sulfoxide in the presence of an alkali catalyst (solvent method: Japanese Patent Publication No. 35-13102) or a method in which water is used without using a solvent and sucrose is melted together with fatty acid soap and then reacted with a fatty acid alkyl ester in the presence of a catalyst (aqueous medium method: Japanese Patent Publication) 51-14485). After removing impurities such as unreacted sugar, fatty acid alkyl ester, and solvent from the reaction products obtained by these synthesis methods, fractionation is performed using a column or the like, and the fractions are appropriately combined and blended. Thus, a sucrose fatty acid ester having the above ester composition can be prepared. Further, a plurality of commercially available sucrose fatty acid esters are mixed and mixed, or alternatively, a commercially available sucrose fatty acid ester is fractionated using a column or the like, and the fractions are appropriately combined and blended, A sucrose fatty acid ester having the above ester composition can also be prepared by blending these fractions in combination with the sucrose fatty acid ester synthesized above or an appropriate fraction thereof.

  The sucrose fatty acid ester according to the present invention can be used as a surfactant in pharmaceuticals, cosmetics, foods and the like. In particular, it is preferably used as an emulsifier for preparing an oil-in-water (O / W) emulsion composition, or as a vesicle forming agent for forming vesicles as microcapsules of active ingredients. Preferable applications include application to various skin external preparations such as a lotion, a moisturizing cream, and a moisture-occlusive cream capable of suppressing moisture evaporation from the epidermis.

  When used as an emulsifier for an oil-in-water emulsion composition, the emulsifier may be composed only of the sucrose fatty acid ester, and together with the sucrose fatty acid ester, an ionic surfactant, glycerin fatty acid ester, propylene Represented by glycol fatty acid ester, sorbitan fatty acid ester, lecithin, polyoxyethylene alkyl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene castor oil, polyoxyethylene glyceryl ether fatty acid ester, alkyl polyglucoside, etc. Other surfactants such as nonionic surfactants may be used in combination. Examples of the ionic surfactant include, but are not limited to, anionic surfactants such as acyl glutamate, stearoyl lactate, sulfosuccinate, and ether carboxylate, alkyl ammonium salts, and organic compounds such as dimethylaminopropyl stearate. Cationic activators such as acid salts and amphoteric activators such as alkyl (amido) betaines and alkyldimethylamine oxides can be mentioned, and it is preferable to use fatty acid soaps having 12 to 22 carbon atoms.

  Examples of the emulsifier include higher alcohols such as stearyl alcohol and cetyl alcohol, sterol derivatives such as phytosterol, natural polysaccharides such as xanthan gum and carbomer, synthetic thickeners, water-soluble polymers, clays Inorganic thickeners such as minerals and silicic anhydride, inorganic powders such as talc, kaolin and mica, organic powders such as polyamide resin powder and polystyrene powder, powders such as organic pigments and pigments, etc., moisturizers, coating agents, ultraviolet rays Absorbers, sequestering agents, amino acids, pH adjusters, skin nutrients, vitamins, antioxidants, perfumes and other foods, cosmetics, and materials commonly used in the pharmaceutical field can be used as appropriate. .

  Although the compounding quantity of the said sucrose fatty acid ester in an oil-in-water type emulsion composition is not specifically limited, It is preferable that it is 0.5-30 weight%, More preferably, it is 1-10 weight%.

  In the oil-in-water emulsion composition, the aqueous phase that is a continuous phase includes water and various aqueous solutions. Ethanol, propylene glycol, butylene as water-soluble ingredients to be blended in various skin external preparations such as cosmetics and pharmaceuticals. You may mix | blend polyhydric alcohols, such as glycol, and saccharides, such as a monosaccharide and an oligosaccharide. Also, the oil phase which is a dispersed phase is not particularly limited, and synthetic oils represented by silicone oil such as methyl silicone and dimethyl silicone, higher fatty acids such as stearic acid and isostearic acid, and minerals such as paraffin and mineral oil Examples thereof include oils and hydrocarbons, ester oils such as isopropyl palmitate and isopropyl myristate, natural fats and oils such as animal and vegetable oils, and waxes such as beeswax and carnauba wax. The oil-in-water emulsified composition may also be blended by dispersing powders or pigments that do not dissolve in the water phase and oil phase.

  Hereinafter, the present invention will be specifically described by way of examples, but the scope of the present invention is not limited thereto.

1. Preparation of Sucrose Fatty Acid Esters Sucrose fatty acid esters (stearic acid / palmitic acid = 75/25 (weight ratio)) having the ester composition shown in Table 1 and FIG. 1 were prepared. The preparation was carried out according to the method described in “Determination of Sucrose Fatty Acid Esters by High-performance Liquid Chromatography” (J. Oleo Sci., Vol. 50, No. 4, 2001, p249-254). It fractionated by HPLC and performed by mixing each ester as needed.

  Analysis of the ester composition is by gel filtration chromatography (GPC). Specifically, the conditions are as follows: column: Megapak GEL 201 (manufactured by JASCO Corporation), 20 mmφ × 500 mm × 2, eluent: tetrahydrofuran, flow rate: 3 ml / min, detector: RI, column temperature: room temperature, 500 mg of a sample and 200 mg of lauric acid (internal standard substance) were dissolved in 10 ml of tetrahydrofuran, and 60 μl of this solution was injected and analyzed. And the content of each ester was computed by correct | amending the area ratio of the peak area of each ester part and internal standard substance in the obtained chromatogram with relative sensitivity.

2. Evaluation of Transparency of Aqueous Solution A 4% by weight aqueous solution was prepared for each sucrose fatty acid ester obtained above. Specifically, 4 parts by weight of each sucrose fatty acid ester powder was added to 96 parts by weight of ion-exchanged water, and the mixture was stirred and dissolved at 80 ° C (TK homomixer (manufactured by Koki Kogyo Co., Ltd.). / Disper blade / 1500 rpm / 15 minutes). Then, it was made to cool to 60 degreeC and transparency evaluation was performed in five steps visually according to the following evaluation criteria.

  The evaluation criteria were “」 ”for transparent,“ ◯ ”for translucent,“ Δ ”for slightly turbid,“ × ”for white turbid,“ xxx ”for insoluble.

  The results are as shown in Table 1 and FIG. 2 below. When the polyester component above the triester exceeded 35% by weight, it was not completely transparently dissolved. Further, when the amount of the polyester component was more than 35% by weight, even if the polyester component was uniformly dispersed and swollen in water, it separated into an aqueous phase and a sucrose fatty acid ester swollen phase with time.

3. Evaluation of Water Retention Capacity of Aqueous Solution Using the 4 wt% aqueous solution prepared in the above-described transparency evaluation, thermogravimetric analysis (TG) was performed with a thermal analysis system “SSC / 5200 TG / DTA220” manufactured by Seiko Instruments Inc. . Two thermal histories (temperature raising conditions) were used, the first condition and the second condition.

  The first condition is to raise the temperature from 30 ° C. to 80 ° C. at 1 ° C./min. The sample amount was unified to about 8 mg. And the presence or absence of the water | moisture content loss in steps was observed from the obtained differential curve, this was made into the moisture loss characteristic, and the result was shown in Table 1 and FIG. In the tables and figures, “1” indicates that the weight change is one step, “2” indicates two steps, “3” indicates three steps, and “2-3” indicates two steps. And 3 stages of intermediate weight loss behavior.

  Further, in the first condition, the amount of water remaining at the point of transition from the first-stage moisture evaporation to the second-stage moisture evaporation as determined from the differential peak (when water used for the sample is 100, On the other hand, the remaining water (% by weight) was calculated. The results are shown in Table 1 (remaining moisture after one stage) and FIG.

  The second condition is to hold at a constant temperature of 40 ° C. for 1 hour, and the moisture content (% by weight) in the sample remaining after holding was measured. The sample amount was unified to about 10 mg. The results are shown in Table 1 (constant temperature test moisture remaining amount) and FIG.

  As shown in Table 1 and FIG. 3, moisture transpiration was not stepwise in the range where the monoester component was more than 35% by weight. In general, the water taken in the lamellar phase is difficult to evaporate, and the other free water is easy to evaporate. Only is considered to exist. Therefore, in the range where the monoester component is more than 35% by weight, it cannot be said that sufficient moisture has been taken into the obtained lamellar phase, and as shown in FIGS. It was an end.

  Further, as apparent from the remaining amount of water in the constant temperature test shown in FIG. 5, the water retention ability was significantly improved by setting the diester component to 55% by weight or more.

4). Evaluation of Viscosity of Emulsion Liquid Oil-in-water emulsion liquid was prepared using each sucrose fatty acid ester obtained in 1 above as an emulsifier. For the preparation of the emulsion, 4 parts by weight of each sucrose fatty acid ester powder was added to 80 parts by weight of ion-exchanged water, and the mixture was stirred and dissolved at 80 ° C. (TK homomixer (Special Machine Industries, Ltd. Manufactured) / disper blade / 1500 rpm / 15 minutes). Thereafter, 16 parts by weight of soybean white squeezed oil was added and emulsified (TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) / Homomixer blade / 8000 rpm / 5 minutes).

  Using the E-type viscometer ("RE-80R" manufactured by Toki Sangyo Co., Ltd.) attached to the temperature control equipment, 1 ml of each sample was injected and the resulting emulsion was rotated for 3 minutes with a rotor speed of 100 rpm. The viscosity (mPa · s) at 20 ° C. was measured.

The results are as shown in Table 1 and FIG. 6, and are in the range of monoester: diester: polyester (more than triester) = 5-14 wt%: 55-65 wt%: 26-35 wt% In the sucrose fatty acid ester, the viscosity was specifically high.

  From the above results, when the ester composition of the sucrose fatty acid ester is monoester: diester: polyester = 5 to 14 wt%: 55 to 65 wt%: 26 to 35 wt%, when dissolved in water It has excellent solubility and water retention ability (and therefore excellent moisturizing properties when used in skin preparations such as cosmetics). Furthermore, the viscosity of the oil-in-water emulsion composition can be specifically increased. did it.

  The sucrose fatty acid ester according to the present invention can be used as a surfactant in the fields of pharmaceuticals, cosmetics, foods, etc., and is particularly suitable as an emulsifier for preparing an oil-in-water (O / W) emulsion composition. Used.

It is a triangular graph which shows the ester composition of sucrose fatty acid ester. It is a triangular graph of the ester composition which shows the transparency evaluation result of aqueous solution. It is a triangular graph of the ester composition which shows the water retention ability evaluation (water loss characteristic) of aqueous solution. It is a triangular graph of the ester composition which shows the water retention ability evaluation (water content after one step) of aqueous solution. It is a triangular graph of the ester composition which shows the water retention ability evaluation (constant temperature test water residual amount) of aqueous solution. It is a triangular graph of the ester composition which shows the viscosity measurement result of an emulsion.

Claims (2)

A sucrose fatty acid ester having a fatty acid having 12 to 22 carbon atoms as a constituent fatty acid, the monoester component having a degree of esterification of 5 to 14% by weight, the diester component having a degree of esterification of 2 to 55 to 65% by weight, and An emulsifier for an oil-in-water emulsion composition, comprising a sucrose fatty acid ester comprising an ester component of 26 to 35% by weight having an esterification degree of 3 or more. An emulsified composition using the emulsifier according to claim 1 .

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