JP4681439B2 - Water-in-oil emulsion composition - Google Patents

Description

  The present invention relates to a water-in-oil emulsified composition, and particularly relates to improvement of emulsion stability, improvement of moisturizing effect on skin, and further improvement of usability.

  The emulsified compositions are roughly classified into an oil-in-water type (O / W) and a water-in-oil type (W / O), and further, an oil-in-water type (O / W / O), a water-in-oil-in-water type ( There are also multiple types such as (W / O / W). These have been conventionally used in skin care creams, emulsions, hair care creams, etc. in the cosmetics field, and as transdermal creams, etc. in the pharmaceutical field.

  Among them, a water-in-oil type emulsion composition in which the oil phase is the outer phase and the water phase is the inner phase efficiently contains oil-soluble active ingredients such as emollient oil, oil-soluble drugs, and UV absorbers on the skin. Since it can be developed, it is a dosage form suitable as a skin external preparation, and is superior to the oil-in-water type in this respect.

  The ratio of the inner aqueous phase obtained by dividing the amount of the inner aqueous phase component by the total emulsified composition has a great influence on the properties of the emulsion, and also in the cosmetics containing the emulsion. Specifically, in a water-in-oil emulsified composition utilized for creams and the like, it is possible to give a refreshing and good feeling when the internal water phase ratio is increased, and the internal water phase ratio is low and moist. It feels oily.

  In a normal water-in-oil emulsion composition, when the internal water phase ratio is increased, it becomes difficult to maintain stability at around 60%. This is because the water molecules that make up the emulsified particles in the inner aqueous phase migrate and are absorbed by other emulsified particles (Ostwal Dryening), and the emulsified particles are more This is because coalescence of the emulsified particles occurs due to a significant increase in the collision frequency. Therefore, it was difficult to stabilize the emulsion at an internal water phase ratio exceeding 70%, which is around the fine packing ratio (74%) of the hard spheres. In addition, since the emulsification system is thermodynamically non-equilibrium, in order to stabilize it so that it can be used industrially, the amount of emulsifier, the ratio of the internal water phase, the type and amount of the aqueous component, the oil content There were limitations on the use of types and amounts, types and amounts of other stabilizers.

  That is, it has been difficult to provide a water-in-oil emulsion composition having a high moisturizing effect on the skin, having a high internal water phase ratio suitable for enhancing usability and maintaining good stability. .

  On the other hand, by using polyether-modified silicone as an emulsifier, water-in-oil emulsified cosmetics with high stability and high internal water phase ratio have been developed (see, for example, Patent Document 1 and Patent Document 2). In this method, it is recommended to use a polyether-modified silicone having a high molecular weight (30000 or more). However, polyether-modified silicone usually exhibits a behavior as a polymer surfactant and has a problem of giving a sticky feeling due to entanglement of polymer chains.

  Further, a water-in-oil emulsion composition having a high internal water phase ratio has been developed by mainly using sucrose polyester as a surfactant (see, for example, Patent Document 3). However, emulsified cosmetics prepared using a sugar surfactant tend to give a generally sticky feeling to use. In particular, when emulsion preparation is performed using sucrose fatty acid polyester, it is clear from the fact that liquid crystals are easily formed from a low concentration compared to polyoxyethylene nonionic surfactants frequently used in the cosmetics field. The hydration power was strong and sticky, and the refreshing feeling was not sufficient.

  In addition, there is a technique for obtaining a water-in-oil emulsion composition having a high internal water phase ratio using a partially hydrophilized crosslinked polysiloxane and applying it to cosmetics (for example, see Non-Patent Document 1). When preparing an emulsion by this method, there has been a problem that the emulsified composition is easily destabilized by blending oil other than cyclic silicone, nonpolar oil, polar oil, linear silicone and the like. In particular, it is difficult to blend non-polar oils, and there are significant restrictions on the blending of oils as components useful for the skin, and there are functional limitations such as effects on the skin, UV protection, and restrictions on the feeling of use.

Furthermore, a water-in-liquid type emulsion composition having a high internal water phase ratio in which a discontinuous reverse micelle cubic liquid crystal filled with reverse micelles is used as an outer phase and water is taken in as emulsion droplets has been developed (for example, Non-Patent Document 2). reference). However, in this method, the types and amounts of surfactants and oils are remarkably limited, so that the practicality is poor and the storage stability is not satisfactory.
JP 2001-89356 A JP 2002-201355 A JP 9-239259 A Satsuki Kuribayashi, Oreoscience Vol.1. No.3, 247-254 (2001) WATANABE et al., J. Oleo Sci., Vol. 51, No. 12, 771-779 (2002)

As a result of devising the surfactant used to increase the internal water phase ratio, the conventional method has a sticky feeling and has a problem in usability, and is stable while maintaining a high internal water phase ratio. In order to maintain the quality, there are limitations on the types of oils to be blended, and the quality of cosmetics is not always satisfactory.
The present invention has been made in view of the above-mentioned problems of the prior art, and has a high internal water phase ratio with good usability while being a water-in-oil emulsion composition having a high moisturizing effect on the skin, Another object of the present invention is to provide a water-in-oil emulsion composition having good emulsion stability.

  As a result of intensive studies by the present inventors to solve the above-mentioned problems, (A) a glyceryl monooleate, (B) a surfactant having a branched chain in an alkyl group, (C) an aqueous component, and (D) A water-in-oil emulsified composition containing an oily component has a high moisturizing effect on the skin, a high internal water phase ratio with good usability, and good emulsification stability, completing the present invention. It came to do.

  The water-in-oil emulsion composition is obtained by dividing the mass of the aqueous component of component (C) by the sum of the mass of the aqueous component of component (C) and the oily component of component (D). The phase ratio is 70% or more. Further, the content ratio of the glycerin fatty acid diester and / or the glycerin fatty acid triester contained in the oil phase as a kind of oil component blended as the oil component of the component (D) or as an impurity of the component (A) is the component (D). It is characterized by not exceeding 20% with respect to the oily component.

  The water-in-oil emulsion composition is prepared by mixing the aqueous component (C), the glyceryl monooleate (A), and the surfactant having a branched chain in the alkyl group (B). The obtained phase equilibrium state is a multi-phase state in which a bicontinuous cubic liquid crystal and an aqueous phase, or a bicontinuous cubic liquid crystal and another phase and an aqueous phase coexist.

  Further, the surfactant having a branched chain in the alkyl group of the component (B) of the water-in-oil emulsion composition is tetramethyltrihydroxyhexadecane (trade name: phytantriol), polyoxyethylene isostearate, polyoxyethylene. It is characterized by being one or more selected from either isostearyl ether or polyoxyethylene glyceryl isostearate. Further, when a surfactant having a branched chain in the alkyl group of the component (B) is selected, it has an average 5 to 15 mol of polyoxyethylene moiety in the molecular structure. Features.

  The mass ratio of the glyceryl monooleate of component (A) of the water-in-oil emulsion composition to the surfactant having a branched chain in the alkyl group of component (B) is 1: 1 to 5: 1. And

  A cyclic silicone oil is included as the oil component of the component (D) of the water-in-oil emulsion composition.

The total amount of the glyceryl monooleate component (A) of the water-in-oil emulsion composition and the surfactant having a branched chain in the alkyl group of the component (B) is 1.0 to the mass of the total composition. It is 3.0 mass%.

  Furthermore, the glycerin fatty acid diester and / or the glycerin fatty acid triester contained in the oil phase as an impurity of the component (A) glyceryl monooleate is less than 25% by mass of the component (A), and the oily property of the component (D) It is characterized in that glycerin fatty acid diester and / or glycerin fatty acid triester is not contained in the component.

  The water-in-oil emulsion composition according to the present invention comprises a component (A) glyceryl monooleate, a component (B) surfactant having a branched chain on the alkyl group, a component (C) aqueous component and a component (D). A water-in-oil emulsion composition that is obtained by mixing the oily components, has good emulsification stability, has a high moisturizing effect on the skin, and has good usability.

  The water-in-oil emulsion composition according to the present invention comprises (A) glyceryl monooleate, (B) a surfactant containing a branched chain in an alkyl group, (C) an aqueous component, and (D) an oil component. . Hereinafter, each component will be described in detail.

  Component (A) glyceryl monooleate can be provided by various known synthetic methods. According to the usual synthesis method, it is produced as a mixture of glyceryl monooleate, glycerin dioleate, and glyceryl trioleate. The component (A) glyceryl monooleate constituting the water-in-oil emulsion composition according to the present invention preferably has a high purity. As a purification method of glyceryl monooleate, a molecular distillation method is usually used, but is not limited thereto.

  The glycerin fatty acid diester and / or glycerin fatty acid triester contained as impurities of the glyceryl monooleate of component (A) is preferably less than 25%, more preferably less than 10% of component (A). The glycerin fatty acid diester and / or glycerin fatty acid triester contained in the oil phase as a kind of oil component blended as the oily component of component (D) and as an impurity of component (A) is an oily component of component (D) It is preferable not to exceed 20%, more preferably not to exceed 10%, with respect to the total mass. While glyceryl monooleate has a function as a surfactant (emulsifier), glycerin dioleate and / or glycerin trioleate behaves as an oil component. Therefore, when the purity of glyceryl monoleate is low, the emulsion behaves as if glycerin dioleate and / or glyceryl trioleate were blended as an oil component in addition to the oil component of component (D). That is, the purity of glyceryl monooleate is low, and the glycerin fatty acid diester and / or glycerin fatty acid triester contained as an impurity of the component (A) as a kind of oil blended as the oil component of the component (D) is a component ( When it exceeds 10% with respect to the total mass of the oil component of D), the stability of the emulsion tends to be impaired.

  Surfactant having a branched chain in the alkyl group of component (B) is tetramethyltrihydroxyhexadecane (trade name: phytantriol), polyoxyethylene isostearic acid ester, polyoxyethylene isostearyl ether, polyoxyethylene glyceryl isostear It is preferable that it is 1 type, or 2 or more types chosen from either of the rates. Tetramethyltrihydroxyhexadecane has four branched chains. Moreover, polyoxyethylene isostearic acid ester, polyoxyethylene isostearyl ether, and polyoxyethylene glyceryl isostearate have polyoxyethylene in the molecular structure. A property that these structures provide when forming an emulsion is prevention of crystallization at low temperatures. The average number of moles of the polyoxyethylene chain is preferably 5-15. If it is less than 5, the stability at low temperature is not sufficient, and if it exceeds 15, the hydrophilicity of the mixture of component (A) glyceryl monooleate and component (B) increases, and as a preparation of a water-in-oil emulsion composition, It is inappropriate.

  As the surfactant having a branched chain in the alkyl group of the component (B), one or two or more commonly used cosmetics can be selected as long as the stability is not impaired. The mass ratio of the glycerin monooleate of component (A) and the surfactant having a branched chain in the alkyl group of component (B) is preferably 1: 1 to 5: 1. Mixing the surfactant having a branched chain in the alkyl group of the component (B) with the emulsion composition of the present invention has an effect of supplementing and improving the property that the glyceryl monooleate of the component (A) is easily crystallized at a low temperature. Bring. When the mixing ratio of the component (A) and the component (B) is out of the range of 1: 1 and a large amount of the component (B) is blended, the emulsion stability at high temperature becomes insufficient, and conversely the range of 5: 1. If a large amount of component (A) is added, the crystallization at low temperature becomes a problem and the stability becomes insufficient.

Further, the smaller the total amount of component (A) and component (B), the refreshing feeling is given, and the total mass of pure glycerin monooleate and component (B) contained in component (A) is based on the total mass. Te is preferably 1.0 to 3.0 wt%. If it is less than 1.0 % by mass, the function as an emulsifier is not sufficiently exhibited, and a stable emulsified state cannot be obtained. Moreover, when it exceeds 3.0 mass%, an emulsion composition may come to have a sticky feeling.

As the aqueous component of component (C), those that can be usually used for cosmetics, pharmaceuticals and the like can be blended within a range that does not impair the stability of the emulsion. Examples of the humectant include 1,3-butylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, glycerin, diglycerin, xylitol, maltitol, maltose, D-mannitol and the like. Water-soluble polymers include gum-based polymers such as gum arabic, carrageenan, pectin, agar, quince seed (quince), starch, and alge colloid (brown algae extract), microbial polymers such as dextran and pullulan, collagen, and casein. Animal polymers such as gelatin, starch polymers such as carboxymethyl starch and methylhydroxypropyl starch, alginic acid polymers such as sodium alginate, vinyl polymers such as carboxyvinyl polymer (such as CARBOPOL), polyoxyethylene -Based polymers, polyoxyethylene-polyoxypropylene copolymer-based polymers, acrylic polymers such as sodium polyacrylate and polyacrylamide, and inorganic water-soluble polymers such as bentonite, aluminum magnesium silicate, and laponite.
Examples of UV absorbers include benzoic acid UV absorbers such as paraaminobenzoic acid, anthranilic acid UV absorbers such as methyl anthramylate, salicylic acid UV absorbers such as octyl salicylate and phenyl salicylate, isopropyl paramethoxycinnamate, Cinnamic acid UV absorbers such as octyl paramethoxycinnamate and glyceryl mono-2-ethylhexanoate diparamethoxycinnamate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy Benzophenone UV absorbers such as 4-methoxybenzophenone-5-sulfonic acid, urocanic acid, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 4-tert-butyl-4'-methoxybenzoylmethane Etc.
Examples of the sequestering agent include sodium edetate, sodium metaphosphate, phosphoric acid and the like.
Examples of the antioxidant include ascorbic acid, α-tocopherol, dibutylhydroxytoluene, butylhydroxyanisole and the like.
Drugs include vitamin A oil, retinol, retinol palmitate, inosit, pyridoxine hydrochloride, benzyl nicotinate, nicotinamide, nicotinic acid DL-α-tocopherol, magnesium ascorbate phosphate, 2-glucoside ascorbate, vitamin D2 ( Ergocassipherol), dl-α-tocopherol 2-L ascorbic acid phosphate diester potassium salt, dl-α-tocopherol, dl-α-tocopherol acetate, pantothenic acid, biotin and other vitamins, allantoin, azulene and other anti-inflammation Agents, whitening agents such as arbutin, astringents such as zinc oxide and tannic acid, sulfur, lysozyme chloride, pyridoxine hydrochloride, γ-oryzanol and the like.
In addition to the above drugs being used in a free state, those capable of salt formation can be used in the form of an acid or base salt, and those having a carboxylic acid group can be used in the form of its ester.

As the oily component of component (D), those usually usable for cosmetics and pharmaceuticals can be used as long as the stability of the emulsion is not impaired. Silicone oil is preferred, and cyclic silicone oil is more preferred. Examples of silicone oils include linear silicone oils such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylhydrogenpolysiloxane, and octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane. The cyclic silicone oil etc. which are represented are mentioned.
It is desirable to mix a small amount of polar oil as long as the stability of the emulsion is not impaired. Of the polar oils, glycerin fatty acid diesters and glycerin fatty acid triesters are undesirable. It is desirable that the total amount of the glycerin fatty acid diester and glycerin fatty acid triester blended as these oil phase components plus the glycerin fatty acid diester and glycerin fatty acid triester contained as impurities of the monooleic acid glycerin component (A) is small. Specifically, it is preferable not to exceed 20% of the total oil phase components, and more preferably not to exceed 10%. When it exceeds 20%, the emulsification stability at high temperature tends to be lowered.
Other polar oils include cetyl octanoate, hexyl laurate, isopropyl myristate, octyl palmitate, isocetyl stearate, isopropyl isostearate, octyl isopalmitate, isodecyl oleate, 2-ethylhexyl succinate, diethyl sebacate, etc. And ester oils represented by
Examples of the nonpolar oil include hydrocarbon oils typified by liquid paraffin, squalane, squalene, paraffin, isoparaffin, sesilene and the like.

  The internal water phase ratio of the water-in-oil emulsion composition according to the present invention is 70% or more. If it is less than 70%, a refreshing feeling may not be obtained. Furthermore, in the present invention, it is possible to prepare a water-in-oil emulsion composition having a high internal water phase ratio of 80% or more, and it is possible to give a refreshing feeling to use.

  It is known that cubic liquid crystals have four types of structures. Closed aggregate micelles or reverse micelles form cubic surfaces by discontinuous cubic liquid crystals and lipid bilayers that are three-dimensionally connected in cubic layers in continuous layers of oil or water, respectively. There is a bicontinuous cubic liquid crystal which is a bicontinuous structure arranged in the same manner. Bicontinuous cubic liquid crystals also have a reverse type in which the positions of water and oil are reversed. The emulsified composition in the present invention is a phase equilibrium state obtained by mixing an aqueous component of component (C), glyceryl monolenate of component (A) and a surfactant having a branched chain in the alkyl group of component (B). However, the component (C), the component (A) and the component (B) are in a multiphase state in which the bicontinuous cubic liquid crystal and the aqueous phase, or the bicontinuous cubic liquid crystal and the other phase, and the aqueous phase coexist. ).

A bicontinuous cubic liquid crystal is a bimolecular film in which surfactants are infinitely associated and arranged in a cubic form. Appearance is transparent, optically isotropic, and presents a highly viscous gel. Bicontinuous cubic liquid crystal discriminating methods include judgment by appearance, creation of phase equilibrium diagram, electrical conductivity measurement, self-diffusion coefficient measurement by NMR, small-angle X-ray scattering, freeze fracture method Determined by observation with an electron microscope or the like.
As a method for discriminating the liquid crystal structure in the present invention, the following methods can be considered. First, glycerin monooleate as component (A), surfactant having a branched chain on the alkyl group of component (B) and aqueous component (C) are mixed well, and then a plurality of coexisting phases are obtained by centrifugation. To separate. When a normal centrifugal separator is used, a processing time of several hours to several days may be required. If there is no coexisting phase and it is in a single phase, the whole is uniformly transparent. Bicontinuous cubic liquid crystals including the reverse type are transparent in appearance, optically isotropic, and exhibit a highly viscous gel. Optical isotropy can be determined from the fact that the sample is held while two polarizing plates are combined with a phase difference of 90 degrees and there is no light transmission. The appearance is transparent and optically isotropic, and the gel-like phase with high viscosity can be further identified by small-angle X-ray scattering. The scattering pattern of the bicontinuous cubic liquid crystal including the inverted type is √2, √3, √4, √6, √8, √9, or Ia3d for the structure called Pn3m. The peak ratio is √6, √8, √14, √16, √20.
As a simple alternative to small-angle X-ray scattering, water- and oil-soluble dyes are used as described in H. Kunieda et al., J. Oleo Sci. Vol. 52, 429-432 (2003). There is also a method for estimating the structure from the diffusion time.

  In addition, the water-in-oil emulsion composition according to the present invention can be widely applied to cosmetics, pharmaceuticals, and quasi-drugs that have been conventionally applied to the outer skin. For example, whitening serum, milk, cream, pack, foundation, lipstick, eye shadow, eyeliner, mascara, face wash, spray, mousse, hair rinse, shampoo, dermatological ointment and the like.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Unless otherwise specified, the blending amount is expressed in mass% with respect to the system in which the component is blended.

Preparation method Mix glyceryl monooleate component (A), surfactant (B) having a branched chain in the alkyl group, component (D) oil component and other oil-soluble components, and heat to about 40 degrees And dissolve. The aqueous component of component (C) and other water-soluble components are mixed and dissolved. The water-soluble component parts are gradually added while stirring the oil-soluble component parts relatively strongly.
Moreover, the purity of the glycerol monooleate of a component (A) can be measured by general methods, such as gas chromatography (GC), gel permeation chromatography (GPC), and a high performance liquid chromatography (HPLC).
The internal water phase ratio of the water-in-oil emulsion composition obtained by the above preparation method is calculated by dividing the mass of water and water-soluble components by the total mass of water and water-soluble components and oil and oil-soluble components. The

Evaluation Method of Water-in-oil Emulsion Composition The compositions shown in Tables 1 to 6 below were evaluated for emulsion stability, moisturizing effect on skin, feeling of use, and phase balance based on the following evaluation criteria.
1. Emulsification stability at high temperature Stability was visually evaluated after storage at 40 ° C for one month.
A: Separation of water and / or oil is not observed at all.
○: Slight separation of water and / or oil is observed.
X: Separation of water and / or oil is clearly observed.
2. Emulsification stability at low temperature After storage at 0 ° C. for one month, the stability was evaluated by observation with an optical microscope.
○: No precipitation of crystals is observed.
Δ: Slight precipitation of crystals is observed.
X: Crystal precipitation is clearly observed.
3. Moisturizing effect on skin After measuring the initial conductance value of the upper arm, the upper arm was degreased with a 5% aqueous solution of sodium lauryl ether sulfate. The conductance value after one week of continuous use of each composition was measured.
A: Recovered to 80% or more of the initial conductance value B: Recovered to 40% to 80% of the initial conductance value.
×: Less than 40% of the initial conductance value.
4). Usability The usability was evaluated by 10 professional panels.
A: Evaluated that 9 or more of 10 people are fresh and refreshing.
○: Evaluated as 7 to 8 out of 10 people being fresh and refreshing.
Δ: Evaluated that 4 to 6 out of 10 people were fresh and refreshing.
X: It is evaluated that 3 or less of 10 people are fresh and refreshing.
5. Phase equilibrium when components (A), (B), (C) were mixed Each component was sufficiently mixed, and then each phase was separated by centrifugation. Thereafter, the phase equilibrium was determined by observation with a polarizing microscope and small-angle X-ray scattering measurement.
A: Bicontinuous cubic liquid crystal and water phase coexist.
○: The bicontinuous cubic liquid crystal coexists with other phases and aqueous phases.
×: Consists of a combination of phases other than bicontinuous cubic liquid crystals.

As is clear from the results shown in Table 1, when ion-exchanged water is less than 70% (Test Examples 1-1 and 1-2), a surfactant having a low HLB is selected to a certain extent. A / O type emulsion composition can be prepared. However, when the ion-exchanged water is 70% or more, the selection of the surfactant and the preparation of the HLB which are conventionally known as providing an emulsion composition having a high internal water phase ratio are sufficiently stable W / An O-type emulsion composition could not be prepared (Test Examples 1-3 to 1-5).
In contrast, in Test Example 1-6 in which glyceryl monooleate and phytantriol were used in combination, an excellent stable W / O emulsion composition could be prepared.
Then, the present inventors examined the improvement mechanism of the emulsion composition by the combination of glyceryl monooleate and phytantriol.

As shown in Table 2, in Test Examples 2-1 to 2-7, the total blending amount of glyceryl monooleate and phytantriol was set to 1%, and the blending ratio was adjusted to 9: 1 to 2: 3. Then, each emulsion stability was examined.
As a result, it was found that when both coexist, the emulsion stability tends to be excellent compared to the case where each of them is alone, but excellent stability can be obtained particularly at 1: 1 to 5: 1.
When the total amount of glyceryl monooleate and phytantriol was 4% (Test Example 2-8), there was no problem in stability, but the feeling of use tended to decrease. Similarly, when the total blending amount was 0.1% (Test Example 2-9), the stability tended to decrease.
From the above results, the blending ratio of glyceryl monooleate and phytantriol is preferably 1: 1 to 5: 1, and the total amount is 4% or less, particularly 1.0 to 3.0% by mass in the composition. It is understood that is preferred.
Next, the present inventors further investigated the phase state and the emulsion stability of the W / O type emulsion composition having a high internal water phase ratio.

As shown in Table 3, the total amount of glyceryl monooleate and phytantriol is 3%, and the purity of glyceryl monooleate is adjusted to 90%, 75%, and 45%. The influence of the / O type emulsion composition on the phase state and emulsion stability was investigated.
As a result, when the purity of glyceryl monooleate is 90% (Test Example 3-1), the composition is excellent in emulsion stability, but when the purity is 75% (Test Example 3-2), phase equilibrium in a state in which other phases than bicontinuous cubic liquid crystals and water coexist, emulsion stability at high temperature decreased slightly. When the purity further decreased to 45% (Test Example 3-3), the phase equilibrium did not contain bicontinuous cubic liquid crystals, and the emulsion stability tended to further decrease.
Moreover, the influence which content of the glycerol fatty acid diester and glycerol fatty acid triester contained in an oil-based component brings to emulsion stability was also examined. As shown in Test Example 3-4, when glyceryl monooleate having a purity of 90% was used and the blending amount of glyceryl triisooctanoate was increased, the emulsion stability was inferior. The ratio of the glycerin fatty acid diester and the glycerin fatty acid triester to the content of the total oil component at this time was 2 2 %. Furthermore, when glyceryl monooleate having a purity of 45% was used and the blending amount of glyceryl triisooctanoate was increased, the emulsion stability tended to decrease gradually. At this time, the total amount of glyceryl fatty acid diester and glycerin fatty acid triester contained in glyceryl monooleate and glyceryl triisooctanoate in other oils was 26 % with respect to the content of all oil components.
From the above results, the presence of glycerin fatty acid diester and glycerin fatty acid triester contained in glyceryl monooleate prevents the formation of bicontinuous cubic liquid crystals and affects the phase state, and in glyceryl monooleate It is understood that the increase in the content of the glycerin fatty acid diester and glycerin fatty acid triester contained in the glycerin fatty acid diester or the glycerin fatty acid diester and glycerin fatty acid triester contained as other components causes a decrease in emulsion stability.
Next, the present inventors have further investigated a surfactant used for maintaining good emulsification stability while being a W / O emulsion composition having a high internal water phase ratio.

As shown in Table 4, one type of surfactant was fixed to glyceryl monooleate (90%) and adjusted to a composition in which the hydrophilic surfactant was changed, and each emulsion stability was examined.
As a result, when a surfactant having a suitable alkyl chain length having a polyoxyethylene structure, which is generally used as an emulsifier for cosmetics, was selected, the emulsion stability was as in Test Examples 4-1 to 4-3. It became clear that it became an excellent composition. However, even with the same polyoxyethylene structure and alkyl chain length, if the surfactant has no branched alkyl group (Test Examples 4-4 and 4-5), crystallization at low temperatures becomes a problem. Emulsification stability decreased. Moreover, even if it is the same alkyl group which has a branched chain, if it does not have a polyoxyethylene structure (Test Example 4-6), the emulsification stability at a low temperature is slightly lowered, and as a hydrophilic surfactant, Since the action was reduced, the feeling of stickiness became stronger and the usability was also lowered.
From the above results, the surfactant used in combination with glyceryl monooleate has a high internal water phase ratio and good stability because it has a polyoxyethylene structure and a branched structure in the alkyl group. It is understood that it is preferable for the preparation of a W / O type emulsion composition retaining the same. In this regard, it was suggested that the co-phase state of the bicontinuous cubic liquid crystal and water correlates with the quality of the emulsion stability.
Subsequently, the present inventors proceeded with investigation of a surfactant having a branched structure in an alkyl group having a polyoxyethylene structure, which is used in combination with glyceryl monooleate.

As shown in Table 5, one type of surfactant was fixed to glyceryl monooleate (90%) and adjusted to a composition in which the chain length of the polyoxyethylene part was changed with respect to the hydrophilic surfactant, The emulsification stability of was examined.
As a result, Test Example 5-1 in which the POE chain was 5 was a phase equilibrium between the bicontinuous cubic liquid crystal and water, and was excellent in emulsion stability. On the other hand, as the POE chain becomes longer as in Test Example 5-2 in which the POE is 18 and further in Test Example 5-3 in which the POE is 30, the proportion of the phase equilibrium occupied by other phases that are not bicontinuous cubic liquid crystals It is understood that there is a tendency to increase the emulsion stability. Particularly in Test Examples 5-3 and 5-4 in which the POE is 30, the hydrophilicity as a surfactant that acts complementarily with the glyceryl monooleate used in combination increases more than necessary, so the W / O type It becomes a combination unsuitable for preparation as an emulsified composition. Moreover, it is as having shown in Test Example 4-6 of the said Table 4 that the emulsion stability in low temperature will fall if it does not have a POE chain | strand.
As described above, in order to obtain a W / O type emulsion composition with excellent emulsion stability while having a high internal water phase ratio, it is important to combine moderately hydrophilic and lipophilic surfactants. It is understood that the surfactant combined with glyceryl monooleate preferably has a branched structure in the alkyl chain having an average POE chain of 5 to 15 mol.
Furthermore, the present inventors proceeded with studies on other oily components to be blended in preparing a W / O type emulsion composition having a high internal water phase ratio and excellent emulsion stability.

As shown in Table 6, the surfactant was fixed to glyceryl monooleate and POE (8) glyceryl isostearate, and other oil components were changed to examine the emulsion stability.
As a result, Test Examples 6-1 and 6-2 containing silicone oil are excellent in stability, and when both are compared, Test Example 6-1 containing a cyclic silicone oil is particularly excellent. Understood. On the other hand, in Test Example 6-6 containing no silicone oil, the stability is not sufficient, although not as much as that of polar oil.
Furthermore, when focusing on oily components other than silicone oil, Test Example 6-3 containing 5% glyceryl triisooctanoate had reduced emulsion stability. In addition, in Test Example 3-1 of Table 3 above, although it was a composition containing glycerin triisooctanoate, the content ratio was as small as 2%, so the emulsion stability was not impaired, and therefore it depends on the blending amount. Understood.
Also, when a natural oil such as olive oil having an emollient effect was blended (Test Example 6-4) and when a wax such as liquid lanolin was blended (Test Example 6-5), the emulsion stability decreased. . From the above results, the ester oil blended in Test Examples 2-3, 2-4 and 2-5 in Table 2 and the hydrocarbon oil blended in Test Example 6-1 in Table 6 It is understood that it is preferably formulated as an oily component (see FIG. 1).

As the oil contained in the water-in-oil emulsion composition according to the present invention, a region in which stability after storage for 1 month at 40 ° C. when using decamethylcyclopentasiloxane, liquid paraffin, and glycerin triisooctanoate FIG.

Claims (5)

A water-in-oil emulsion composition comprising the following components (A), (B), (C), and (D) and further satisfying the following conditions (1) to (3) :
Component: (A) Glycerol monooleate (B) Surfactant having a polyoxyethylene chain having an average mole number of 5 to 15 and having a branched chain in the alkyl group , or tetramethyltrihydroxyhexadecane (C) aqueous component ( D) Oil component conditions: (1) The internal water phase ratio obtained by dividing the mass of the aqueous component of component (C) by the sum of the mass of the aqueous component of component (C) and the oil component of component (D) 70% or more.
(2) The glycerin fatty acid diester and / or glycerin fatty acid triester contained as an impurity of the component (A) is less than 25% of the component (A), and the oil component blended as the oil component of the component (D) The content ratio of the glycerin fatty acid diester and / or the glycerin fatty acid triester contained in the oil phase as one kind or as an impurity of the component (A) does not exceed 20% with respect to the total mass of the oily component of the component (D). .
(3) The mass ratio of the component (A) and the component (B) is 1: 1 to 5: 1, and the total mass of the component (A) and the component (B) is 1.0 to the total mass. 3.0% by mass. The composition according to claim 1, wherein the phase equilibrium obtained by mixing the component (C) with the component (A) and the component (B) is a bicontinuous cubic liquid crystal and an aqueous phase, or bicontinuous. A water-in-oil emulsion composition characterized by being in a multiphase state in which a cubic liquid crystal and other phases and an aqueous phase coexist.   The composition according to claim 1 or 2, wherein the surfactant having a branched chain in the alkyl group of component (B) is selected from polyoxyethylene isostearate, polyoxyethylene isostearyl ether, and polyoxyethylene glyceryl isostearate. A water-in-oil emulsion composition, which is one or more selected from the group consisting of: The composition in any one of Claims 1-3 WHEREIN: Cyclic silicone oil is included as an oil-based component of a component (D), The water-in-oil emulsion composition characterized by the above-mentioned. Te composition scent of any of claims 1-4, Ingredient water-in-oil emulsion composition, characterized in that the oily component does not include a glycerin fatty acid diester and / or glycerol fatty acid triester of (D) object.

Images