JPH0356776B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-in-oil (hereinafter referred to as W/O) emulsion composition, and more particularly to a W/O emulsion composition that has excellent storage stability over a wide temperature range. Conventionally, as a base for creams, emulsions, etc., so-called W/O emulsions, in which water particles are dispersed in oil, are generally used as oil-in-water (hereinafter referred to as O/W) emulsions.
It is known to be superior to emulsions in many respects, such as protection of the skin and imparting flexibility. However, W/O emulsion has the disadvantage of poor quality stability compared to O/W emulsion. Generally, separation of emulsions occurs due to creaming (or sedimentation), aggregation, and coalescence of emulsion particles, but in W/O emulsions, water droplets tend to aggregate at low temperatures, resulting in syneresis, that is, The continuous oil phase is easy to separate. On the other hand, at high temperatures, the particle size increases due to the coalescence of water droplets, and as a result, the water droplets tend to settle, leaving only the oil phase in the upper layer, which tends to cause separation of the oil phase. If the coalescence proceeds further, separation of the aqueous phase will occur.
Therefore, it has been difficult to obtain a W/O emulsion that is stable over a wide temperature range. For example, the well-known W/O emulsifier
W/O emulsions using lipophilic nonionic surfactants with ethylene oxide chains as hydrophilic groups, such as POE(3) oleyl ether, are relatively stable at low temperatures, but coalesce at high temperatures. It is easily separated into two phases when stored at 50℃ for one month. Also, special public service 1977-015798
No. 55-31037, etc., describe stable emulsions in which a fatty acid partial ester of a polyhydric alcohol is used as an emulsifier and a polyhydric alcohol is added thereto. When we tried making a prototype, we found that the stability at high temperatures was improved, but the stability at low temperatures was poor, resulting in agglomeration of water droplets and separation of the oil phase. Furthermore, in order to improve the stability at low temperatures in these systems, a large amount of wax is added to the oil phase to solidify it, but as a natural consequence of increasing the viscosity of the oil phase, it is difficult to maintain fluidity and stability. It is not possible to obtain a W/O emulsion. In addition, since it feels difficult to use and feels sticky, the degree of freedom in formulating the formulation may be limited. Therefore, the inventor of the present invention improved the drawbacks of the prior art and created a W/O that is extremely stable over a wide temperature range.
As a result of systematically performing a large amount of experiments on combinations of many emulsifiers and auxiliary ingredients in order to obtain Elsion, we found an emulsifier that does not cause separation due to aggregation of water droplets at low temperatures, and also added one or more types of emulsifiers. The present inventors have discovered that the addition of a specific water-soluble substance with a molecular weight of 2,000 to 300,000 is very effective in stabilizing emulsions at high temperatures, and have completed the present invention. That is, the present invention provides (a) a branched alkyl group having 16 to 25 carbon atoms or an alkenyl group having 16 to 22 carbon atoms as a lipophilic group, and an ethylene oxide chain as a hydrophilic group, and has an HLB value. 1 to 10% by weight of one or more nonionic surfactants of 5 to 12, (b) 5 to 80% by weight of one or more liquid oils, (c) one or more of The present invention provides a water-in-oil emulsion composition comprising 0.1-20% by weight of polyethylene glycol having a molecular weight of 2,000-300,000 and (d) 20-90% by weight of water. The composition according to the present invention has extremely good storage stability over a wide temperature range compared to conventional compositions. Furthermore, according to the present invention, stabilization is achieved without solidifying the oil phase with wax and increasing its viscosity, so a stable and fluid W/O emulsion composition (emulsion) can be obtained. When making a non-flowing cream, it is easy to obtain a cream that spreads well and has a refreshing texture. Furthermore, since the emulsion composition according to the present invention has very good stability, it is possible to obtain a stable W/O emulsion with a very high internal phase ratio, which was difficult to achieve with conventional techniques. Next, the configuration of the present invention will be described. The nonionic surfactant used in the present invention has a branched alkyl group having 16 to 25 carbon atoms or an alkenyl group having 16 to 22 carbon atoms as a lipophilic group, and an ethylene oxide chain as a hydrophilic group, and
It is a nonionic surfactant with an HLB value of 5 to 12.
Examples of these include polyoxyethylene (3) oleyl ether, higher alcohol ethers such as polyoxyethylene (4) arachidonate and polyoxyethylene (5) 2-decyltetradecyl ether, and polyoxyethylene (3) glyceryl ether. POE glyceryl ether fatty acid esters such as monoerucate, polyoxyethylene (6) glyceryl ether dipalmitoolate, polyoxyethylene (15) glyceryl ether triisostearate, polyoxyethylene (10) pentaerythritol ether triisothearate, etc. POE pentaerythritol ether fatty acid ester, POE trimethylolpropane fatty acid ester such as polyoxyethylene (15) trimethylolpropane toquarate, POE such as polyoxyethylene (3) sorbitan monooleate, polyoxyethylene (7) sorbitan diolate, etc. Examples include POE sorbitol fatty acid esters such as sorbitan fatty acid ester, polyoxyethylene (10) sorbitol tetraoleate, and POE sugar fatty acid esters such as polyoxyethylene (10) sugar tetraisostearate. One or more types are selected and used from these. Emulsion stabilizers using surfactants with lipophilic groups having less than 16 carbon atoms do not work well.
Furthermore, alkenyl groups having 23 or more carbon atoms and branched alkyl groups having 26 or more carbon atoms are currently difficult to obtain. Further, these surfactants are blended in an amount of 1 to 10% by weight, preferably 2 to 10% by weight, based on the weight of the composition. If the amount added is less than 1% by weight, the composition cannot be stabilized, and if it exceeds 10% by weight, it will give a sticky feeling when used as a cosmetic, which is not preferable. The liquid oil is an oil for cosmetics that is liquid at room temperature. These can be used alone or in combination, and specific examples include hydrocarbon oils such as sulfalane and liquid paraffin, ester oils such as isopropyl myristate and cetyl octanoate,
Vegetable oils such as olive oil, silicone oils, etc.
The amount of these oils applied is 5 to 80% by weight, preferably 10 to 70% by weight of the composition. Generally, the higher the internal phase ratio of an emulsion, the higher the viscosity of the emulsion. Therefore, by changing the amount of the oil used, it is possible to obtain a highly viscous emulsion and a low viscosity emulsion from a creamy one. However, if the amount of the oil used is less than 5% by weight, emulsification is difficult, and the amount is preferably 10% by weight or more. Also, the amount used
When it exceeds 70% by weight, the properties of the oil itself become stronger,
This is not preferable because it reduces the advantage of emulsifying the oil. In some cases, waxes may be used in combination with the liquid oil to adjust the viscosity or hardness of the composition.
These waxes include ceresin wax, microcrystalline wax, solid paraffin,
Examples include petrolatum, lanolin, and beeswax. These may be used alone or in combination, and from the viewpoint of stickiness, the amount used is usually 25% by weight or less of the weight of the composition. The molecular weight of the polyethylene glycol used in the present invention is 2000 to 300000, preferably 3000 to 100000.
More preferably, it is 3,000 to 20,000. Those with a molecular weight of less than 2000 do not contribute to stabilizing emulsification.
Moreover, if the molecular weight exceeds 300,000, the contribution to stabilization will be small, and when the composition is used as a cosmetic, there will be a drawback that the composition will feel sticky when used. The amount of these compounds used is 0.1 to 20% by weight, preferably 0.2 to 10% by weight, more preferably 1 to 10% by weight, based on the weight of the composition.
It is 10% by weight. If it is less than 0.1%, it will not be possible to stabilize the emulsion, and if it is more than 20% by weight, it will cause stickiness when used as a cosmetic, which is not preferable. The W/O emulsion composition of the present invention includes the above (a), (b), and (c).
In addition to the essential ingredients in (d), surfactants other than (a), waxes, humectants, preservatives, fragrances, ultraviolet absorbers, antioxidants, medicinal agents, dyes, pigments, etc. Various additives can also be used. In order to further understand the present invention, experimental examples are given below. All parts in the examples are by weight. Experimental Example Components having the following composition were heated to 70°C, stirred and mixed, and then emulsified to prepare an emulsified composition. The prepared emulsified form was examined by electrical conductivity, the emulsified particle size by a microscope, and was stored at each temperature for 30 days, and its stability was examined by the state of separation and changes in particle size. The results are shown in Table 1. (Composition) Liquid paraffin 47 parts Surfactant 3 parts Water 48 parts Water-soluble substance 2 parts In Experimental Examples 11 to 15, water was substituted for the water-soluble substance in the above composition components.

【table】

【table】

[Table] Stability evaluation criteria:
− No separation + Slight separation of oil or water phase Separation of oil or water phase Separation into three phases: cream phase, oil phase, and water phase +++++ Separation into two phases: oil phase and water phase Experimental example according to the present invention The emulsion compositions of 1 and 2 are -5
After storage for 30 days at ℃, 25℃ and 50℃, no separation or change in particle size was observed under any of the temperature conditions. On the other hand, in the emulsified compositions of Experimental Examples 3 to 10, slight separation of the aqueous phase was observed after 30 days. In addition, in Experimental Examples 11 to 19, separation of both the aqueous phase and the oil phase was observed after just 7 days of storage at 50°C, and after 30 days, there was almost separation into two layers, the aqueous phase and the oil phase, and there were no emulsified particles. Summer. Example 1 Skin lotion composition (1) Liquid paraffin 13 parts (2) Olive oil 5 parts (3) Squalane 10 parts (4) Lanolin 2 parts (5) Polyoxyethylene (3) Sorbitan monooleate 4 parts (6) Butyl paraoxybenzoate 0.1 part (7) Fragrance 0.2 part (8) Water 57.6 parts (9) Methyl paraoxybenzoate 0.1 part (10) Polyethylene glycol (molecular weight 7000) 3 parts (11) Glycerin 5 parts Manufacturing method (1) ~ Dissolve (6) uniformly at 70℃, and separately dissolve (8) to (11).
Uniformly dissolve at 70℃ and add (8) to (8) to the mixture of (1) to (6).
The mixture of (11) was added with stirring, and after emulsifying with a homomixer, (7) was added, and after cooling to room temperature while stirring, the mixture was filled into a container. The W/O type skin lotion produced in this example was compared with a conventional W/O type skin lotion having the following composition in terms of storage stability and cosmetic properties. (Composition) Conventional W/O type skin lotion (comparative product) (1) Liquid paraffin 30 parts (2) Olive oil 5 parts (3) Lanolin 2 parts (4) Beeswax 1 part (5) Microlistarin wax 1 part (6) Sorbitan sesquiolate 5 parts (7) Butyl paraoxybenzoate 0.1 part (8) Fragrance 0.2 part (9) Water 50.6 parts (10) Methyl paraoxybenzoate 0.1 part (11) Glycerin 5 parts Storage stability -10℃, 0℃, 25℃, 37℃, 50℃
It was evaluated after 30 days of storage. The skin lotion obtained in this example was stable under any temperature conditions. On the other hand, the comparison product is -10
The oil was stable at 37°C, 0°C, and 25°C, but separated in one week at 37°C and in one day at 50°C. In addition, a sensory test was conducted using a blind pair test method with eight expert panelists regarding the feeling of use. The results are shown in Table 2.

[Table] As shown by these results, the product of the present invention was extremely superior in both stability and usability compared to the comparative product. Example 2 Cleansing lotion (composition) (1) Liquid paraffin 30 parts (2) Vaseline 5 parts (3) Polyoxyethylene (3) Oleyl ether 5 parts (4) Fragrance 0.2 parts (5) Methyl paraoxybenzoate 0.1 Part (6) Water 44.7 parts (7) Propylene glycol 10 parts (8) Polyethylene glycol (molecular weight 20000)
5-part manufacturing method Dissolve (1) to (3) uniformly at 70℃, and separately dissolve (5) to (8) at 70℃.
Dissolve uniformly at ℃, add the mixture of (5) to (8) into the mixture of (1) to (3) with stirring, emulsify with a homomixer, add (4), and warm to room temperature while stirring. After cooling, it was filled into a container. The W/O type cleansing lotion produced in this example had extremely good stability when stored for one month at temperatures of -10°C, 0°C, 25°C, 37°C and 50°C. Furthermore, in the results of a usage test conducted by 30 panelists, 29 people answered that the cleansing lotion of the present invention removes makeup makeup better than conventional O/W type cleansing lotions. . Example 3 Hair creel oil composition (1) Liquid paraffin 28 parts (2) Polyoxyethylene (5) 2-decyltetradecyl ether 8 parts (3) Fragrance 0.2 parts (4) Water 53.7 parts (5) Benzoic acid Methyl 0.1 part (6) Polyethylene glycol (molecular weight 3000) 15 parts (7) Glycerin 5 parts Manufacturing method Dissolve (1) to (3) uniformly at room temperature, and separately stir (4) to (7) at room temperature. dissolve. (4) to (7) in the mixture of (1) to (3)
was added with stirring, and the mixture was further emulsified with a homomixer and then filled into a container. The W/O type hair cream oil produced in this example was stored at temperatures of -10°C, 0°C, 25°C, 37°C and 50°C for one month, and was stable under all temperature conditions. It was extremely good. Example 4 Hand cream (1) Liquid paraffin 10 parts (2) Vaseline 3 parts (3) Polyoxyethylene (6) Sorbitol tetraoleate 4 parts (4) Butyl benzoate 0.1 part (5) Water 72.8 parts (6) Benzoin Methyl acid 0.1 part (7) Polyethylene glycol (molecular weight 4000) 5 parts (8) Glycerin 5 parts (manufacturing method) Dissolve (1) to (4) uniformly at 50°C, and separately dissolve (5) to (8) at 50°C.
After uniformly dissolving at °C, (5) to (8) were gradually added to the mixture of (1) to (4) with stirring, and then cooled to room temperature while stirring. The W/O type hand cream obtained in this example has a very high internal phase ratio and a large amount of aqueous phase compared to conventional W/O type products, so it has a very small amount of water even though it is a W/O type. It gave a firm feeling of use and was liked.

Claims (1)

[Scope of Claims] 1 (a) having a branched alkyl group having 16 to 25 carbon atoms or an alkenyl group having 16 to 22 carbon atoms as a lipophilic group, and an ethylene oxide chain as a hydrophilic group, and HLB 1.0 to 10% by weight of one or more nonionic surfactants having a value of 5 to 12, (b) 1
(c) 0.1-20% by weight of one or more types of polyethylene glycol having a molecular weight of 2,000-300,000; and (d) 20-90% by weight of water. Water-in-oil emulsion composition. 2 25% by weight of one or more types of waxes
A composition according to claim 1, hereinafter included.