JP4627831B2 - Method for producing oil-in-water emulsion - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an oil-in-water emulsion, and more particularly to a method for producing an oil-in-water emulsion that has high stability of emulsified particles and can be used for cosmetics, cleaning agents, and the like.
[0002]
[Prior art]
Conventionally, as a technique of using a clay mineral in producing an emulsion, for example, a method of stabilizing an oil-in-water emulsion without dispersing a clay mineral in water and using a surfactant (Japanese Patent Laid-Open No. 58-86). No. 124535, etc.), and a method of dispersing a cation-modified clay mineral in oil to form a water-in-oil emulsion (Japanese Patent Laid-Open No. 62-216635) is known. In addition, a technique for forming an oil gel with a surfactant, an oil component and a clay mineral is also known (Japanese Patent Laid-Open No. 54-79183). Further, JP-A-8-126833 discloses (A) (a) 1 to 10 mol of ethylene oxide in a partial ester of a polyhydric alcohol and a fatty acid having at least 3 hydroxyl groups in the molecule and a fatty acid triglyceride. A substance exhibiting a liquid state at room temperature selected from the group of added substances, and (b) an aqueous solution containing at least 0.1% of one or more of amino acids and / or salts thereof, b) a water-in-oil emulsifier composition having a weight ratio of 1: 1 to 1:46, (B) an organically modified clay mineral 0.1 to 10.0%, and (C) a silicon oil 1 to 1 A water-in-oil emulsion having good usability and stability containing 20% is disclosed, and the water-in-oil emulsion disperses the organically modified clay mineral (B) and the silicon oil (C). Then, the above (A) Are those prepared by Ete allowed to disperse.
All of these prior art methods use a clay mineral on the continuous phase side to increase the viscosity of the continuous phase and stabilize the dispersed phase. That is, those using unmodified clay minerals make use of the aqueous properties to form a swollen structure in the aqueous phase, and those using organically modified clay minerals make use of the oily properties to make the oil phase. The system is stabilized by forming a swollen structure therein.
[0003]
[Problems to be solved by the invention]
The present invention provides a method for producing a stable emulsion using an oily component, a nonionic surfactant and a clay mineral.
[0004]
[Means for Solving the Problems]
As a result of intensive research on the formation of a stable emulsion, the present inventors have improved the stability of the emulsified particles themselves by blending a clay mineral with a specific component in the dispersed phase and emulsifying it by a specific method. As a result, it was found that a fine and stable oil-in-water emulsion was obtained, and the present invention was completed.
[0005]
That is, the present invention resides in the following (1) to (2).
(1) At least an oily component, a nonionic surfactant, a clay mineral and a small amount of water are mixed to prepare a viscous oil phase in which the clay mineral is dispersed, and the oil phase and the water phase are mixed. Emulsifying and emulsifying the oil-in-water emulsion.
(2) At least an oily component, a nonionic surfactant, a clay mineral, and a low molecular weight polyhydric alcohol are mixed to prepare a low-viscosity oil phase in which the clay mineral is dispersed. Is gradually added to carry out phase inversion emulsification, and a method for producing an oil-in-water emulsion.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the method of the present invention, an oil phase is prepared by mixing at least an oil component, a nonionic surfactant, a clay mineral, and (a) a small amount of water or (b) a low molecular weight polyhydric alcohol. An oil-in-water emulsion is produced by mixing and emulsifying the aqueous phase.
[0007]
Examples of the oil component used for the preparation of the oil phase in the method of the present invention include hydrocarbons, animal and vegetable oils, silicone oils, synthetic oils and the like, and those that are liquid at room temperature are preferably used. Specific examples of the oil component include liquid paraffin, squalane, olive oil, jojoba oil, corn oil, soybean oil, coconut oil, palm oil, dimethyl silicone oil, methyl phenyl silicone oil, cyclic dimethyl silicone oil, isopropyl myristate, myristic acid. Examples thereof include octyldodecyl and isopropyl palmitate.
[0008]
In addition, as nonionic surfactant , So Rubitan fatty acid ester, polyglycerin fatty acid ester, polyethylene glycol fatty acid ester The Examples include polyether-modified silicone. In the present invention, those which are liquid at room temperature are preferably used. Specific examples of such nonionic surfactants , So Rubitan monooleate, sorbitan sesquioleate, diglyceryl monooleate, decaglyceryl pentaoleate, polyoxyethylene (2) monooleate The Examples thereof include a methylsiloxane / methyl (polyoxyethylene) siloxane copolymer and a dimethylsiloxane / methyl (polyoxyethylene) siloxane / methyl (polyoxypropylene) siloxane copolymer. In addition, when HLB is too high, there exists a tendency for it to become difficult to adjust to an oil-based component.
[0009]
Examples of clay minerals include smectite viscosity such as natural or synthetic bentonite, montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, and stevensite. Soil These may be used alone or in combination of two or more. In the present invention, non-organically modified clay minerals are particularly preferably used.
[0010]
In the method of the present invention, in preparing the oil phase, (a) a small amount of water or (b) a low molecular weight polyhydric alcohol is mixed, but the purpose of mixing these differs depending on the state of the oil phase.
(A) A small amount of water is used for the purpose of easily increasing the viscosity of the oil phase. The oil phase is prepared by mixing three components of an oil component, a nonionic surfactant and a clay mineral. Used when the viscosity of the oil phase when prepared is about 0.1 to 3 Pa · s. On the other hand, the low molecular weight polyhydric alcohol (b) is used for the purpose of suppressing an increase in the viscosity of the oil phase, and comprises mixing three components: an oil component, a nonionic surfactant and a clay mineral. It is used when the viscosity of the oil phase when the oil phase is prepared is about 50 Pa · s or more. Which method should be selected depending on the system to be used depends on mixing the oil component, nonionic surfactant and clay mineral to determine the viscosity when the equilibrium is reached. Can be determined. Here, a small amount of water as component (a) is added in a small amount separately from the water originally retained by the clay mineral. In the present invention, the “small amount of water” may be an amount that allows the clay mineral to maintain a continuous phase and maintain an appropriate viscosity, and specifically, 1 to 20% by mass (based on the dried clay mineral ( Hereinafter simply referred to as “%” )of Moisture range And , Preferably 3 to 10%. In the present invention, the degree of viscosity varies depending on the amount of the component (a). When the amount of water is small within the above range, the oil phase viscosity is low, and when there is much water, the oil phase viscosity is high. In general, a higher oil phase viscosity is preferred because the retention of oil when emulsified particles tend to be stronger, but if the viscosity is too high, the oil phase may be poorly dispersed. If the amount of water used is less than 1%, it will be absorbed within the range of the amount of water originally carried by the clay mineral (vibration width), so that a sufficient effect cannot be obtained.
[0011]
Examples of the (b) low molecular weight polyhydric alcohol include ethylene glycol, propylene glycol, butylene glycol, sorbitol, dipropylene glycol, and glycerin. Here, “low molecular weight” means that the carbon number of the alkyl chain portion in the polyhydric alcohol is about 2 to 6. The The blending amount of the polyhydric alcohol is 15 to 50% with respect to the nonionic surfactant. And In particular, 20 to 35% is more preferable. If the blending amount of polyhydric alcohol is small, the system may thicken, and if it is too large, emulsification may not be successful.
[0012]
The aqueous phase in the present invention contains water as a main component, but it is possible to appropriately mix arbitrary components as will be described later.
[0013]
Next, the preparation method and the emulsification method of the oil phase in the present invention will be described separately for (a) when a small amount of water is used and (b) when a low molecular weight polyhydric alcohol is used.
[0014]
First, preparation of a viscous oil phase using the component (a) is performed by mixing an oily component, a nonionic surfactant, a clay mineral, and a small amount of water. A clay mineral and water are dispersed in the mixture, and then a nonionic surfactant is added and mixed. Here, “viscous” generally means a state where the viscosity is high, but in the present invention, it means that the viscosity is about 3.5 to 40 Pa · s, and preferably about 5 to 30 Pa · s. . Although mixing of each component can be performed in the normal operation range of a stirrer, since the viscosity increases during mixing, it is preferable to use blades that can be easily mixed at high viscosity. Examples of the stirrer that can be used include a paddle mixer, an azimuth homomixer, and a hibis disper mix. The mixing temperature is preferably about room temperature to 90 ° C. Mixing is performed until the viscosity of the system increases and becomes viscous. The rise time of the viscosity of the system varies depending on the mixing force and temperature, but as a guide for the mixing time, about 10 minutes to 2 hours is preferable. In addition, the viscosity can be increased in a shorter time when the mixing force is stronger. The viscous oil phase prepared as described above is in a state where the layer structure of the clay mineral is dispersed and dispersed in a dispersion medium composed of a nonionic surfactant and an oil component. (A) When the oil phase is prepared using the component, the ratio of each component is in the range of 1/10 to 1/4 for the ratio of the nonionic surfactant to the oil component. It is. In particular, the range of 1/8 to 1/5 is preferable. The ratio of clay mineral to oil component is in the range of 1/10 to 1/4. It is. In particular, the range of 1/8 to 1/5 is preferable. However, the above range is merely an example, and the present invention is not limited to this. The viscosity level of the oil phase formed by the four components of the oil component, the nonionic surfactant, the clay mineral, and water is about 3.5. If it becomes about -40 Pa.s, you may remove | deviate from the said range.
[0015]
In addition, emulsification of the viscous oil phase obtained using the component (a) includes (1) a method in which the oil phase is added to the aqueous phase under high shear to emulsify, and (2) the aqueous phase is converted into the oil phase. It is carried out by a method of adding and emulsifying under high shear, (3) a method of gradually adding an aqueous phase to the oil phase and emulsifying by phase inversion. When the viscosity of the oil phase is not so high (for example, when it is approximately 15 Pa · s or less), the method of adding (1) or (2) under high shear and emulsifying is preferable.
As the emulsification conditions in the above methods (1) and (2), it is preferable that the emulsifying power is at a high shear level, that is, a normal use range of a homomixer. The emulsification temperature is preferably in the range of room temperature to about 90 ° C., and the emulsification time is preferably set until uniform emulsified particles are formed (about 10 minutes to 2 hours is a guide).
On the other hand, when the viscosity of the oil phase is high (for example, when it exceeds approximately 15 Pa · s), it is difficult to transfer the oil phase itself. A method in which the water phase of the above (2) is added to the oil phase under high shear and emulsified, or (3) a method in which the water phase is gradually added to the oil phase to perform phase inversion emulsification is preferable. The conditions of the method (2) are as described above. As conditions for phase inversion emulsification (3), the emulsifying power is preferably set to the agitator level of the azimuth homomixer, and the emulsifying temperature is preferably in the range of room temperature to about 90 ° C. In phase inversion emulsification, the water phase is gradually added to the oil phase. Here, “gradually” is added depending on the size of the emulsifying pot. For example, in the case of an emulsifying pot that can be mixed with 1 ton, the rate of adding about 50 kg of the aqueous phase in about 3 to 10 minutes is a rough indication. However, since the aqueous phase is difficult to adjust, especially at the beginning of the addition, it is preferable to add it little by little. Moreover, you may divide and add required amount (for example, about 3 to 20 divisions). The emulsification time is preferably about 30 minutes to 2 hours in all steps when gradually added, and in the case of divided addition, it is possible to emulsify about 5 to 20 minutes after adding each aqueous phase related to the division. preferable.
In the formation of the emulsion, the ratio of the oil phase to the aqueous phase is preferably about 1:10 to 1: 1, particularly about 1: 5 to 1: 2.
In addition, for example, antibacterial agents, preservatives, pigments, fragrances, and the like can be blended in the oil phase as optional components. For example, water-soluble polymers, preservatives, antibacterial agents, alcohols, A monohydric alcohol, a pigment, and the like can be blended as optional components. Furthermore, for example, a pigment such as titanium oxide can be dispersed in advance in an aqueous phase or an oil phase.
[0016]
On the other hand, (b) preparation of a low-viscosity oil phase using a low molecular weight polyhydric alcohol is performed by mixing an oil component, a nonionic surfactant, a clay mineral, and a low molecular weight polyhydric alcohol. Preferably, the clay mineral is dispersed in the oil component, and a mixture of a nonionic surfactant and a polyhydric alcohol is added thereto and mixed. Here, “low viscosity” generally indicates a low viscosity state, but in the present invention, it means that the viscosity is in the range of about 0.01 to 3 Pa · s. Here, the viscosity level at the time of preparation of the oil phase is different from that when (a) a small amount of water is added, because this is because the polyhydric alcohol lowers the viscosity of the oil phase. Even if the phase has a low viscosity, a stable particle formation is similarly achieved by performing phase inversion emulsification thereafter.
Although mixing of each component can be performed in the operation range of a normal stirrer, since the viscosity increases in the phase inversion emulsification step, it is preferable to use blades that can be easily mixed at high viscosity. Examples of the stirrer that can be used include a paddle mixer, an azimuth homomixer, and a hibis disper mix. The mixing temperature is preferably about room temperature to 90 ° C. Mixing is carried out until the entire system is familiar, and as a guide, it is preferably about 30 minutes to 2 hours.
The low-viscosity oil phase prepared as described above has a slightly lamellar clay mineral structure and is dispersed in a dispersion medium composed of a nonionic surfactant and an oil component, but has a low viscosity. Therefore, when the stirring is stopped, the clay mineral is in a state of sedimentation.
[0017]
(B) When the oil phase is prepared using the component, the ratio of each component is in the range of 1/4 to 1/1 for the ratio of the nonionic surfactant to the oil component. It is. In particular, a range of 1/4 to 1/2 is preferable. Moreover, about an oil-based component and a clay mineral, it is the range of 1 / 4-1 / 1. In particular, a range of 1/4 to 1/2 is preferable. The ratio of the polyhydric alcohol (b) is 15 to 50% with respect to the nonionic surfactant. It is. In particular, the content is preferably 20 to 35%. When the amount of the polyhydric alcohol is small, the viscosity of the oil phase is increased and the dispersion of the oil phase may be poor, and when it is large, the oil phase may be separated. However, the above range is merely an example, and the present invention is not limited to this. The viscosity level of the oil phase formed by the four components of the oil component, the nonionic surfactant, the clay mineral, and the polyhydric alcohol is about 3 Pa. -If it becomes below s, you may remove | deviate from the said range.
[0018]
The obtained low-viscosity oil phase is emulsified by gradually adding a water phase to the oil phase and performing phase inversion emulsification. As the conditions for phase inversion emulsification, first, the emulsifying power is preferably set to the agitator level of the azimuth homomixer, and the emulsifying temperature is preferably in the range of room temperature to 90 ° C. In phase inversion emulsification, the water phase is gradually added to the oil phase. Here, “gradually” is added depending on the size of the emulsifying pot. For example, in the case of an emulsifying pot that can be mixed with 1 ton, the rate of adding about 50 kg of the aqueous phase in about 3 to 10 minutes is a rough indication. However, since the aqueous phase is difficult to adjust, especially at the beginning of the addition, it is preferable to add it little by little. Moreover, you may divide and add required amount (for example, about 3 to 30 divisions). The emulsification time is preferably about 30 minutes to 2 hours in all steps when gradually added, and in the case of divided addition, it may be emulsified every 5 to 20 minutes after the addition of each aqueous phase related to the division. preferable. During the addition of the aqueous phase, the viscosity of the system becomes 30 Pa · s or more, but it is preferable to control the way water is divided within the range allowed by the power of the stirrer.
In the formation of the emulsion, the ratio of the oil phase to the aqueous phase is preferably about 1:10 to 1: 1, particularly about 1: 5 to 1: 2.
The oil phase can contain, for example, antibacterial agents, preservatives, dyes, and fragrances as optional components, and the water phase can contain, for example, water-soluble polymers, preservatives, antibacterial agents, alcohols, and dyes. Etc. can be blended as optional components. Furthermore, for example, a pigment such as titanium oxide can be preliminarily mixed in an aqueous phase or an oil phase.
[0019]
The oil-in-water emulsion of the present invention obtained as described above has high stability of emulsified particles, and can be widely used for various applications such as cosmetics, detergents, pharmaceuticals, and housing-related products.
[0020]
[Action]
The method of the present invention is different from the prior art in that a special structure is formed inside the dispersed phase by using a clay mineral on the dispersed phase side.
That is, it is considered that the emulsified particles of the oil-in-water emulsion obtained by the method of the present invention take a form in which an oil component is encapsulated in a capsule-like structure formed of a clay mineral. For example, the emulsion particles are hardly broken even when mixed with other surfactant micelles (that is, there is little leakage of oily components from the emulsion droplets).
In the method of the present invention, the addition of a small amount of water to the oil phase can promote the thickening of the oil phase composed of the oil component, nonionic surfactant and clay mineral, or the oil phase By adding a low molecular weight polyhydric alcohol, the oil phase can be prevented from becoming highly viscous and a fine oil-in-water emulsion can be formed while maintaining the fluidity of the oil phase.
[0021]
【Example】
EXAMPLES Next, although an Example and a test example demonstrate this invention further in detail, this invention is not restrict | limited to these. In addition, in the following examples etc., the description of “parts” means all parts by mass.
[0022]
Example 1
Dimethylpolysiloxane {trade name SH200 30cs (centistokes); manufactured by Toray Silicone} 6 parts and vegetable squalane (trade name Phytosqualane; manufactured by Iwase Kosfa) 2 parts bentonite (trade name Bengel FW; manufactured by Toyoshun Yoko, weight loss on drying) 8%) 1.6 parts and water 0.08 parts were dispersed, and 1.5 parts of polyether-modified silicone (trade name SH3775M; manufactured by Toray Silicone) was added and mixed at 80 ° C. When the paddle stirring was continued, the viscosity of the system increased in 30 minutes and became 10 Pa · s with a BH viscometer. This was a viscous oil phase.
On the other hand, 8 parts of sorbit (60% solution) was dissolved in 26 parts of purified water to prepare an aqueous phase. The viscous oil phase described above was added to this aqueous phase with stirring with a homomixer and emulsified for 15 minutes. The resulting emulsion had a viscosity of 1070 mPa · s, a particle size of about 1 to 7 μm by microscopic observation, and no oil floating was observed.
[0023]
Example 2
After preparing a viscous oil phase (15 Pa · s) in the same manner as in Example 1 (however, the mixing temperature was 30 ° C.), a total of 34 parts of water was dividedly added in two parts and mixed. The mixing time was 5 minutes with a scraping mixer each time 2 parts of water was added.
The obtained emulsion had a viscosity of 520 mPa · s, a particle size of about 1 to 4 μm under microscopic observation, and no oil floating was observed.
[0024]
Example 3
Disperse 1.8 parts of bentonite (trade name Kunipia F; Kunimine Kogyo Co., Ltd., loss on drying 7%) and 0.1 part of water in 10 parts of vegetable squalane (trade name Phytosqualane; made by Iwase Kosfa), and polyoxy 1.8 parts of ethylene (3) glyceryl monoisostearate (trade name GWIS-103; manufactured by Nippon Emulsion Co., Ltd.) was added and mixed at 50 ° C. When the paddle stirring was continued, the viscosity of the system increased in 30 minutes and became 7 Pa · s with a BH viscometer. This was a viscous oil phase. On the other hand, 5 parts of sorbit (60% solution) was dissolved in 30 parts of purified water to prepare an aqueous phase. When these were emulsified in the same manner as in Example 1, an emulsion having a viscosity of 1530 mPa · s and a particle size of 1 to 7 μm was obtained. No oil floating on the surface of the emulsion was observed.
[0025]
Example 4
Disperse 2 parts of bentonite (trade name Bengel FW; made by Toyoshun Yoko Co., Ltd., loss on drying 7.5%) and 0.2 part of water in 12 parts of isopropyl myristate (trade name IPM-EX; made by Nikko Chemicals) 2.2 parts of polyoxyethylene (12) diisostearate (trade name 600di-IS; manufactured by Nippon Emulsion Co., Ltd.) was added and mixed at 40 ° C. When the paddle stirring was continued, the viscosity of the system increased in 30 minutes and became 6 Pa · s in the BH type viscosity system. When this was used as a viscous oil phase and emulsified in 35 parts of purified water in the same manner as in Example 1, an emulsion having a viscosity of 2050 mPa · s and a particle size of 1 to 8 μm was obtained. No oil floating on the surface of the emulsion was observed.
[0026]
Comparative Example 1
Of the composition shown in Example 1, an oil phase was prepared in the same process as in Example 1 without adding a small amount of water. As a result, the viscosity of the system increased by 1 Pa · s, The time was 2.5 Pa · s. The liquid phase was emulsified in the same manner as in Example 1. The obtained emulsion had properties of a viscosity of 2200 mPa · s, a particle size of about 1 to 10 μm by microscopic observation, and a small amount of coarse oil droplets. Was observed.
[0027]
Example 5
An oil-in-water emulsion was prepared by the following composition and production method.
<Composition>
(1) Oil phase
Oil component: 6 parts dimethylpolysiloxane
(SH200 30cs made by Toray Silicone)
Nonionic surfactant: 2 parts of polyether-modified silicone
(SH3775M manufactured by Toray Silicone)
Clay mineral: bentonite 2.2 parts
{Kunimine Industries Kunipia F (8% loss on drying)}
Polyhydric alcohol: 0.5 parts propylene glycol
Pigment: 0.05 parts of titanium oxide
Transparent iron oxide 0.004 parts
(2) Water phase
30 parts of purified water
[0028]
<Manufacturing method>
(1) Preparation of oil phase
A clay mineral and a pigment were dispersed in the above oil component, and a mixture of a nonionic surfactant and a polyhydric alcohol was added thereto, and the mixture was mixed at 80 ° C. for 1 hour using an Ajihomo mixer. The viscosity of the oil phase at this time was 70 mPa · s.
[0029]
(2) Phase inversion emulsification
30 parts of the aqueous phase was divided into 20 parts by 1.5 parts, and 1.5 parts were added to the oil phase in the Ajihomomixer and stirred for 5 minutes. When about 3 parts were added, the viscosity of the system increased, and after 18 parts, the viscosity of the system gradually decreased. The properties of the emulsion at the time when all the aqueous phases were finally mixed were 960 mPa · s in viscosity, the particle diameter was about 1 to 5 μm by microscopic observation, and a clean emulsion without oil floating was obtained. .
[0030]
Example 6
Using an oil phase and an aqueous phase prepared with the same composition as in Example 5, phase inversion emulsification was performed as follows. First, 30 parts of the aqueous phase was divided into 5 parts (1 part, 1 part, 1 part, 20 parts, 7 parts), and after adding each aqueous phase in the Ajihomo mixer as in Example 5, the mixture was stirred for 10 minutes. did. From the time when the fourth 20 parts of the aqueous phase was added, the agitator and the homomixer were used together and stirred for 20 minutes. The maximum viscosity of the system was about 80 Pa · s.
The properties of the emulsion when all the aqueous phases were finally mixed were a viscosity of 1900 mPa · s and a particle diameter of about 1 to 6 μm by microscopic observation, and a clean emulsion without oil floating was obtained. .
[0031]
Example 7
An oil-in-water emulsion was prepared by the following composition and production method.
<Composition>
(1) Oil phase
Oil component: 6 parts of vegetable squalane
(Iwase Kosfa phytosqualane)
Nonionic surfactant: Polyoxyethylene (12) 2.2 parts
Diisostearate
(Japan emulsion 600di-IS)
Clay mineral: Bentonite 2.5 parts
{Kunimine Industries Kunipia F (8% loss on drying)}
Polyhydric alcohol: 0.7 parts of 1,3-butylene glycol
(2) Water phase
30 parts of purified water
[0032]
<Manufacturing method>
(1) Preparation of oil phase
A clay mineral was dispersed in the oil component, and a mixture of a nonionic surfactant and a polyhydric alcohol was added thereto, and the mixture was mixed at 70 ° C. for 1 hour using an Ajihomo mixer. The viscosity of the oil phase at this time was 85 mPa · s.
[0033]
(2) Phase inversion emulsification
30 parts of the aqueous phase was divided into 10 parts by 3 parts, and 3 parts were added to the oil phase in the Ajihomo mixer and stirred for 10 minutes for phase inversion emulsification. The resulting emulsion had a viscosity of 3400 mPa · s, a particle diameter of about 1 to 6 μm by microscopic observation, and a clean emulsion without oil floating was obtained.
[0034]
Example 8
An oil-in-water emulsion was prepared by the following composition and production method.
<Composition>
(1) Oil phase
Oil component: 6 parts isopropyl myristate
(IPM-EX made by Nikko Chemicals)
Nonionic surfactant: 2.4 parts of polyoxyethylene (3)
Glyceryl monoisostearate
(Japan emulsion GWIS-103)
Clay mineral: Bentonite 2.4 parts
{Benguel FW manufactured by Toyoshun Yoko Co., Ltd. (loss on loss of 7.5%)}
Polyhydric alcohol: 0.7 parts of propylene glycol
(2) Water phase
30 parts of purified water
[0035]
<Manufacturing method>
(1) Preparation of oil phase
A clay mineral was dispersed in the above oil component, and a mixture of a nonionic surfactant and a polyhydric alcohol previously added thereto was added, and the mixture was mixed at 60 ° C. for 1 hour using an Ajihomo mixer. The viscosity of the oil phase at this time was 110 mPa · s.
[0036]
(2) Phase inversion emulsification
30 parts of the aqueous phase was divided into 20 parts by 1.5 parts, and 1.5 parts were added to the oil phase in the Ajihomomixer, and the mixture was stirred for 5 minutes for phase inversion emulsification. The properties of the obtained emulsion were a viscosity of 3520 mPa · s, a particle diameter of about 1 to 7 μm by microscopic observation, and a clean emulsion without oil floating was obtained.
[0037]
Comparative Example 2
An oil phase was prepared in the same manner as in Example 5 except that the polyhydric alcohol was excluded. At this time, the viscosity of the oil phase was 300 Pa · s. 30 parts of the aqueous phase was added to this oil phase in a lump and emulsified with an azimuth homomixer, but the formation of emulsified particles of about 1 to 5 μm was slight, and many particles of several to tens of mm remained and were uniform. No emulsion was obtained.
[0038]
【The invention's effect】
According to the method of the present invention, an oil-in-water emulsion having a fine and excellent stability can be produced, and in particular, a clay mineral not subjected to organic modification can be used as a raw material, which is advantageous. The oil-in-water emulsion obtained by the method of the present invention can be used for a wide range of applications such as cosmetics and cleaning agents.
Also, (a) when a small amount of water is used, not only can the viscosity increase of the oil phase formed by mixing oily components, nonionic surfactants and clay minerals be promoted, but also when equilibrium is reached The viscosity of the oil phase can be further increased as compared with the case where water is not used.
In addition, when (b) a low molecular weight polyhydric alcohol is used, the viscosity of the oil phase formed by mixing the oil component, nonionic surfactant and clay mineral increases so much that the fluidity is lost. This ratio is particularly effective at such a ratio, and even with such a ratio, a fine oil-in-water emulsion can be produced while ensuring fluidity. In this case, there is an advantage that the protective effect of the oil component is enhanced as a property of the oil-in-water emulsion.

Claims (4)

At least one oily component to be an oil phase , sorbitan fatty acid ester, polyglycerin fatty acid ester, polyethylene glycol fatty acid ester and polyether-modified silicone, a clay mineral selected from smectite clay , And water in an amount of 1 to 20% by mass with respect to the clay mineral to prepare a viscous oil phase in which the clay mineral is dispersed, and the oil phase and the water phase are mixed and emulsified. The ratio of the nonionic surfactant to the oil component is in the range of 1/10 to 1/4, and the ratio of the clay mineral to the oil component is in the range of 1/10 to 1/4. A method for producing an oil-in-water emulsion. At least one oily component to be an oil phase, one or more nonionic surfactants selected from sorbitan fatty acid esters, polyglycerin fatty acid esters, polyethylene glycol fatty acid esters and polyether-modified silicones, clay minerals selected from smectite clays, and A low-viscosity oil phase in which clay mineral is dispersed is prepared by mixing polyhydric alcohol having 2 to 6 carbon atoms in an amount of 15 to 50% by mass with respect to the nonionic surfactant , Gradual phase emulsification by gradually adding an aqueous phase to the oil phase, and a clay mineral for the oil component in a ratio of the nonionic surfactant to the oil component of 1/4 to 1/1. The ratio of this is the range of 1/4-1/1, The manufacturing method of the oil-in-water type emulsion characterized by the above-mentioned.   The method according to claim 1 or 2, wherein the smectite clay is bentonite.   The method according to claim 1 or 2, wherein the oil component is dimethyl silicone oil, squalane, or isopropyl myristate.