JPH0237209B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel water-in-oil emulsion in which the aqueous phase has a high internal phase ratio.By applying the characteristics of so-called pyroglutamic acid monoglycerides, there are no stability problems due to temperature changes, and it is easy to use. The purpose of the present invention is to provide a water-in-oil emulsion with excellent properties. Water-in-oil emulsions (hereinafter abbreviated as W/O emulsions) are used in the form of cosmetics, pharmaceuticals, foods, and various other chemical industrial products. Particularly in the field of cosmetics, it is considered to be highly practical because it has better affinity with the skin than oil-in-water emulsions, but since the continuous phase is oil, it generally has a grease-like application feel. Even after application, it has a greasy and shiny appearance, and the usability that is desired for cosmetics these days, such as a fresh and refreshing feeling without any strange feeling, is not necessarily satisfied. We have not achieved the desired results. In addition, when the temperature of conventional W/O emulsions increases, the viscosity decreases rapidly, and if left at high temperatures for a long time, the oil component synervises, while if left at low temperatures, the water crystallizes. This tends to destroy the emulsion and cause separation of the aqueous phase components. In order to improve the above-mentioned usability, a method is usually taken to increase the concentration of the aqueous phase in the W/O emulsion, but using a large amount of water or water and polyhydric alcohol can destroy the interfacial film of the emulsion. Separation of water and oil is further facilitated by temperature changes. Attempts to improve the physical properties of W/O emulsions with high internal phase ratios have recently been made in
No. 116280 and Japanese Unexamined Patent Publication No. 116280 and JP-A No. 55-47613, but in any case, it is difficult to ensure the long-term temperature stability that is actually desired as a product. In addition, this kind of product generally has a strong filmy feeling when applied to the skin, gives a strange feeling, and hardly achieves the purpose of usability, which is the function of cosmetics. Therefore, in order to solve the current problems of W/O emulsion in terms of temperature stability and usability, the present inventor conducted intensive research and found that glycerin pyroglutamic acid monofatty acid esters (so-called pyroglutamic acid monoglycerides), We succeeded in completely achieving the intended purpose by incorporating (hereinafter used synonymously) into a specific base component at a constant ratio. That is, in the W/O emulsion of the present invention consisting essentially of the following composition, (A) 1 to 20 parts by weight of glycerin pyroglutamine monofatty acid ester (B) 2 to 20 parts by weight of oil (C) At least 3 parts by weight in the molecule. Polyhydric alcohol having a hydroxyl group higher than 1.5 to 60 parts by weight (D) Water 20 to 85 parts by weight Ratio of oil phase component to water phase component is 1:3 to 1:9
The ratio of (A) and (B) is 1:0.5 to 1:5 (preferably 1:1 to 1:3), and the ratio of (A) and (C) is 1:
The present invention relates to a W/O emulsion having a high internal phase ratio of 0.5 to 1:9 (preferably 1:1 to 1:5), and a cosmetic comprising the emulsion. Although there are various pyroglutamic acid monoglycerides that can be applied to the present invention, pyroglutamic acid monoglyceride represented by the following general formula (), its ethylene oxide adduct or propylene oxide adduct are advantageously used, and one or two of these are preferably used. More than one species is selected and used. General formula () (In the formula, R is a straight chain saturated, straight chain unsaturated, branched saturated fatty acid residue having 6 to 24 carbon atoms, and X, H or
CH ₃ , a, b, c indicate the number of added moles of ethylene oxide or propylene oxide, a+b
+c=0 to 50. ) The method for obtaining the above pyroglutamic acid monoglyceride is to heat-react various monoglycerides and pyroglutamic acid at 140 to 200°C under normal pressure or reduced pressure, without or using a small amount of catalyst, and then add ethylene oxide to the pyroglutamic acid monoglyceride. The propylene oxide adduct and the propylene oxide adduct are produced by a conventional addition reaction. Specific examples of the pyroglutamic acid monoglycerides according to the present invention include common names such as pyroglutamic acid monocaprate, pyroglutamic acid monolaurate, pyroglutamic acid monopalmitate, pyroglutamic acid monostearate, pyroglutamic acid monooleate, and pyroglutamic acid monoisostearate. , pyroglutamic acid monopalmitate (EO) 10 mol adduct, pyroglutamic acid monostearate (P0) 20 mol adduct, etc. These common names are abbreviations for glycerin pyroglutamic acid monofatty acid esters, focusing on the type of fatty acid. Cosmetics to which pyroglutamic acid monoglyceride has been added are already known in Japanese Patent Publication No. 48-31900, but what is disclosed here is that the substance is optionally added to cosmetics, and Example 1 As shown in , it is mainly intended as an oil-in-water vanishing cream (it is known that vanishing cream is an oil-in-water emulsion in Cosmetic Science, December 1, 1976, pp. 269-270). ), it is completely unthinkable to use pyroglutamic acid monoglyceride to obtain a W/O emulsion having a high aqueous phase concentration and a so-called high internal phase ratio as in the present invention. Furthermore, by effectively blending the substance into a base component with a specific composition, it is possible to obtain an emulsion with good temperature stability, which is a characteristic of W/O emulsion that is desirable for its excellent use as a cosmetic. The present invention and the above-mentioned patent are completely different. The oil agent applicable to the W/O emulsion according to the present invention is not particularly limited, and various oils such as hydrocarbons, oils and fats, waxes, higher alcohols, and higher fatty acids may be used depending on the purpose. More than one species is used in combination. Specific examples of polyhydric alcohols having at least trivalent or higher hydroxyl groups in the molecule applicable to the present invention include glycerin, diglycerin, triglycerin, arabite, sorbitol, sorbitan, mannitol, mannitan, malbitol, maltose, etc. be. The present invention is a W/O emulsion having a high internal phase ratio, which is made by adding water to the above three essential components. You need to adjust the proportions. In the present invention, if each component falls outside the specified range, the desired effective W/O emulsion cannot be obtained. That is, the composition ratio of pyroglutamic acid monoglycerides and oil agent is 1:0.5~
1:5, even if the composition ratio of pyroglutamic acid monoglycerides and polyhydric alcohol is within the range of 1:0.5 to 1:9, when the ratio of oil phase component to aqueous phase component exceeds 1:9. Although it is possible to produce a W/O emulsion, it tends to easily undergo phase inversion and become unstable over time. Further, when the ratio of the oil phase component to the aqueous phase component is less than 1:3, separation of the oil phase component is likely to occur over time. The thus obtained W/O emulsion has an increased mechanical strength of the emulsion interfacial film, and the stability of the W/O emulsion is improved due to strong interaction with water. Because it has such flexibility, there is no feeling of film after application, and a product with a good feeling of use can be obtained. The novel W/O emulsion according to the present invention further improves temperature stability by using a water-soluble inorganic acid polyvalent metal salt or a water-soluble organic acid (salt) in addition to the above components. can be achieved. Specific examples of water-soluble inorganic acid polyvalent metal salts include aluminum sulfate, calcium sulfate, magnesium sulfate, calcium chloride, etc., and are preferably used in a proportion of 0.1 to 5 parts by weight per 100 parts by weight of the aqueous phase component. be done. Examples of water-soluble organic acids or salts thereof include glutamic acid, sodium glutamate, sodium pyrrolidonecarboxylate, triethanolamine pyrrolidonecarboxylate, sodium lactate hyaluronic acid, sodium hyaluronate, sodium chondroitin sulfate, etc., and preferably water phase components. It is used in a proportion of 1 to 20 parts by weight per 100 parts by weight. The method for producing the W/O emulsion having a high internal phase ratio of the present invention may be a general method for producing a W/O emulsion. For example, one or two kinds of pyroglutamic acid glycerides may be used alone or together with other surfactants. A method of obtaining a W/O emulsion by dispersing and emulsifying the aqueous phase components by uniformly dissolving in the above oil agent to prepare an oil phase, and adding polyhydric alcohol, water, and the above-mentioned various salts if necessary, or There is no particular limitation on the method of addition, such as by dispersing the components in a desired order. In the present invention, if necessary, other cosmetic ingredients such as fragrances, preservatives, pigments, plasticizers, thickeners, neutralizers, alcohols, ultraviolet absorbers, chelating agents, and humectants (propylene glycol, 1, 3
-butanediol, 1,4-butanediol, polyethylene glycol, etc.) may be added as appropriate. Next, in order to demonstrate how excellent the W/O emulsion of the present invention having a high internal phase ratio is in temperature stability, the water-in-oil cold cream of Example 1 described later and the water-in-oil cold cream of Example 2 of the same invention were used as the present invention. Table 1 below shows the results of stability experiments conducted using a commercially available water-in-oil hand cream and a commercially available water-in-oil hand cream as comparative examples. show. The experimental method was as follows. Test: A cream container filled with 30g of sample is heated to -10℃.
The specimen was kept in a constant temperature room for one month, then taken out, brought to room temperature (20-25°C), left overnight, and observed with the naked eye. Test: A cream container filled with 30g of sample is left in a constant temperature room at 45℃ for 3 months, then taken out and visually observed. Test: A cream container filled with 30 g of sample is left in an aging box that moves from 0°C to 45°C in 48 hour intervals for one month, then taken out and visually observed.

[Table] *Evaluation criteria ○: Stable △: Slightly separated ×: Completely separated As is clear from Table 1 above, in the case of conventional commercial products, all except commercial product 2 was barely stable in the test. It exhibits some kind of separation. In contrast, in the embodiment of the present invention, stability is completely ensured. In particular, we separately investigated leaving the product for 6 months using the test method, but there was no change in stability. Comparative Example 3 was produced in the same manner as in Example 2, except that an equivalent amount of polyoxyethylene (20) sorbitan monolaurate (hydrophilicity: HLB 16.9) was used instead of pyroglutamic acid monolaurate in Example 2, which will be described later. I tried. However, only an O/W emulsion was formed due to phase inversion during the emulsification step. As Comparative Example 4, a W/O emulsion was obtained in the same manner as in Example 2, except that an equivalent amount of sorbitan monooleate (lipophilicity: HLB 5.0) was used instead of pyroglutamic acid monolaurate in Example 2 described later. . The products obtained in Example 2 and Comparative Example 4 were left in two thermostatic chambers at 40°C and 50°C to evaluate their stability. The results are shown below.

[Table] ○: No change ×: Water was removed. These results show that the emulsion of the present invention is excellent in terms of stability. W/O emulsion of Example 8 and JP-A-53
The stability of the emulsion (Comparative Example 5) described in Example 2 of JP-A-116280 was evaluated in the same manner as above. Composition of Comparative Example 5 Liquid paraffin 20.0 (parts by weight) Polyoxyethylene (=30) Sorbitol tetraoleate 3.0 Sorbitol 15.0 Magnesium sulfate 1.0 Purified water 61.0 The results are shown below.

[Table] There was no difference at 40°C, but water separation was observed in the comparative example on the 15th day at 50°C. Thus, the emulsion of the present invention is similar to Comparative Example 5.
It has better high temperature stability than that of Furthermore, for Example 2 and Comparative Example 2, the state of cream hardness due to temperature change was measured using a card meter (attachment diameter φ = 1.1 mm, weight 50 g).
The results of the measurements are shown in Figure 1. From Figure 1, we can see that the temperature range (5
-45℃), in the case of commercially available products, the hardness changes as seen in ordinary creams, making it difficult to put it into practical use, whereas in the present invention, there is almost no change in hardness,
It has been demonstrated that the present invention is superior in this respect as well. Next, a panel of five experts conducted a sensory evaluation of the usability of the emulsion and the commercially available water-in-oil emulsion, and the results are shown in Table 2. The samples were also used in the above stability experiment, and the evaluation items for usability were (1) texture of appearance, (2) ease of spreading, (3) film feeling, (4) refreshing feeling, (5) Stickiness, etc.

[Table] The water-in-oil emulsion obtained as described above is a water-in-oil emulsion with a high aqueous phase concentration, which has been difficult to stabilize in the past, and the aqueous phase component accounts for 90% of the total weight. Since the interfacial film of the emulsion particles is strong, it has excellent stability over time, and the problem of stability due to temperature changes from high to low temperatures has been solved, and it is suitable for long-term storage and mechanical It can withstand shock sufficiently. In particular, when applied to cosmetics, it is possible to obtain a water-in-oil emulsion that has the crisp feel and cool feeling that has been desired in recent years, and it also has the ability to spread during application, which is typical of this type of emulsion. To provide an emulsion that does not give a strange feeling to the skin due to poor elasticity or a filmy feeling, and is water repellent. Furthermore, the water-in-oil emulsion according to the present invention is
Various types of products can be obtained by selecting the composition ratio of the applied ingredients and the oil agent.
The advantages of the present invention can be applied to foods, medicines, film-forming products (eg, paint, car wax, etc.), and various other uses. Next, examples of the present invention will be described. The blending ratio is in parts by weight.

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[Table] 〓Lumitate

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[Table] 〓Ultraviolet absorber appropriate amount

【table】 Example 8 Liquid paraffin 20.0 (parts by weight) Pyroglutamic acid monooleate 4.0 Marbittu 15.0 Purified water 61.0 A water-in-oil emulsion having the above composition.

[Brief explanation of drawings]

FIG. 1 shows the results of measuring the state of cream hardness with a temperature change of the water-in-oil emulsion having a high internal phase ratio of the present invention using a card meter, where Water-in-oil hand cream, Y represents a commercially available water-in-oil hand cream.

Claims (1)

[Scope of Claims] 1. In a water-in-oil emulsion consisting essentially of the following composition, (A) glycerin pyroglutamic acid monofatty acid ester 1 to 20 parts by weight (B) oil agent 2 to 20 parts by weight (C) in the molecule Polyhydric alcohol having at least trivalent or higher hydroxyl group 1.5 to 60 parts by weight (D) Water 20 to 85 parts by weight The ratio of oil phase component to aqueous phase component (weight ratio, the same applies hereinafter) is 1:3 to 1 :9, the ratio of (A):(B) is 1:0.5~1:5, and the ratio of (A):(C) is 1:0.5~
A water-in-oil emulsion having a high internal phase ratio of 1:9. 2 The glycerin pyroglutamic acid monofatty acid ester has the general formula (1) (In the formula, R is a linear saturated, linear unsaturated, or branched saturated fatty acid residue having 6 to 24 carbon atoms, and X is H or
CH ₃ , a, b, c indicate the number of added moles of ethylene oxide or propylene oxide, a+b
+c=0 to 50. 2. A water-in-oil emulsion having a high internal phase ratio as claimed in claim 1, which consists essentially of a compound represented by: ) or a mixture thereof. 3 It consists essentially of the following composition, the ratio of oil phase component to aqueous phase component is 1:3 to 1:9, the ratio of (A):(B) is 1:0.5 to 1:5, and (A) ):(C) ratio is 1:0.5
A cosmetic comprising a water-in-oil emulsion having a high internal phase ratio of ~1:9. (A) Glycerin pyroglutamic acid monofatty acid esters 1 to 20 parts by weight (B) Oil agent 2 to 20 parts by weight (C) Polyhydric alcohol having at least a trivalent or higher hydroxyl group in the molecule 1.5 to 60 parts by weight (D) Water 20-85 parts by weight