JPS61153134A - Manufacture of oil-in-water type emulsion - Google Patents

Abstract

PURPOSE:To manufacture the titled oil-in-water type emulsion which is excellently emulsified by mixing the primary high-concn. oil-in-water type emulsion and a water phase at a temp. lower than the phase transition temp. of the primary high-concn. oil-in-water type emulsion, and emulsifying the mixture. CONSTITUTION:An oil phase at a temp. higher than the phase transition temp. of the primary high-concn. oil-in-water type emulsion and a water phase are mixed in a ratio necessary to obtain a fixed phase transition temp. of the primary high-concn. oil-in-water type emulsion and so that the temp. of the formed primary high-concn. oil-in-water type emulsion may be regulated to a temp. lower than the phase transition temp., and the mixture is emulsified. Then the formed primary high-concn. oil-in-water type emulsion and a water phase at a temp. lower than the phase transition temp. of the primary high-concn. oil-in-water type emulsion are mixed and emulsified to obtain an oil-in-water type emulsion. A cationic surfactant, higher alcohols, and an emulsifier can be used as the oil phase.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing an oil-in-water emulsion in a stable emulsified state. The present invention also relates to a method for simply and reliably producing an oil-in-water emulsion with excellent viscosity stability over time and fluidity, and a stable emulsification state.

BACKGROUND OF THE INVENTION Conventional techniques and their problems Several attempts have been made to produce stable oil-in-water emulsions. For example, Tokuko Sho 57-2
No. 9213 discloses a method for producing oil-in-water emulsion particles from an oil-in-water emulsion in Japanese Patent Application Laid-Open No. 57-72.
No. 34 and No. 57-7235 each describe a method for obtaining an oil-in-water emulsion from an oil-in-polyhydric alcohol emulsion. However, these methods
In both cases, a third substance such as a solvent or a polyhydric alcohol is used to emulsify the emulsification process, which complicates the manufacturing process.

Furthermore, JP-A-56-89832 discloses that by mixing an oil phase with an aqueous phase containing a nonionic surfactant, or mixing a first aqueous phase with an oil phase containing a nonionic surfactant, A method is disclosed in which a nonionic liquid crystal is generated, a second aqueous phase is added to the liquid crystal to obtain a dull emulsion, and a third aqueous phase is further added to the dull emulsion to obtain an oil-in-water emulsion. In this method, liquid crystal formation is essential, and if the oil phase and nonionic surfactant are compatible, their use must be avoided. There is a problem that an activator cannot be used and the selection range of emulsifiers is narrow. In addition, in this method, the finest emul 7.7
The region where particles are generated is determined by the HL, which indicates the maximum amount of water solubilized.
Since it is in the range of liquid crystal phase and rL phase that exist in HLB value higher than B value, HL in a specific range is used as a nonionic surfactant.
It is necessary to use an emulsifier with a B value, and this also limits the range of emulsifier selection. Furthermore, in this method, it is necessary to gradually add the first aqueous phase from the viewpoint of liquid crystal generation time and uniformity, and the fine particles of the liquid crystal are transferred to the liquid crystal as they are to form a stable oil-in-water type. In order to obtain an emulsion, it is necessary to gradually add the second aqueous phase, and when forming a liquid crystal phase or a gluing phase, it is required from a quality standpoint that the aqueous phase or oil phase be added slowly. Therefore, this method is not suitable as an emulsification method in a continuous process. A method is disclosed in which an oil-in-surfactant dull emulsion is obtained by mixing an aqueous phase containing a surfactant and an oil phase, and then an oil-in-water emulsion is produced from this dull emulsion.

However, this method has the disadvantage that it is necessary to prepare a continuous surfactant phase consisting of glycols, water, and a nonionic surfactant, which makes the process complicated.

SUMMARY OF THE INVENTION In view of the above circumstances, the present inventors have discovered that nonionic surfactants as emulsifiers can be selected from a wide range without restrictions in terms of HLB value, compatibility with the oil phase, etc., and that they are suitable for continuous processes. conducted intensive research on a method for easily and reliably producing an oil-in-water emulsion with a stable emulsification state, and as a result, the present invention was completed.The present invention provides a primary highly concentrated oil-in-water emulsion. It consists of a first stage and a second stage to obtain a target oil-in-water emulsion from this primary high-concentration oil-in-water emulsion. and the aqueous phase are mixed and emulsified at a ratio such that the phase transition temperature of the primary high concentration oil-in-water emulsion is constant, and the temperature of the primary high concentration oil-in-water emulsion to be produced is below that phase transition temperature. After obtaining a primary highly concentrated oil-in-water emulsion, in a second step, the primary highly concentrated oil-in-water emulsion is mixed with an aqueous phase having a temperature lower than the phase transition temperature of the primary highly concentrated oil-in-water emulsion,
By emulsifying, the desired oil-in-water emulsion, /
The present invention provides a method for producing a stable oil-in-water emulsion.

That is, the present inventors made emulsions by changing the ratio of oil phase components and water, and measured the phase transition temperature using S, C (differential scanning calorimeter). Water is below a certain value (
It has been found that when the amount of water exceeds a certain level), the phase transition temperature of the emulsion becomes constant.

In the first step, a first high concentration emulsion is made using the necessary amount of water, preferably the minimum amount of water, to maintain a constant phase transition temperature of the emulsion, and then in the second step, a first high concentration emulsion is prepared. The present invention was made based on the finding that an emulsion with excellent quality such as viscosity and fluidity can be obtained by adding water to the emulsion.

According to the present invention, first, the oil phase and the aqueous phase are arranged in a ratio that makes the phase transition temperature of the emulsion constant, that is, the aqueous phase necessary to create a hydrated structure, preferably the minimum amount of the aqueous phase and the oil phase. Emulsify according to the ratio,
By creating a stable, highly concentrated oil-in-water emulsion and then adding water again to emulsify and disperse it, it is possible to form emul 7.7 particles with extremely uniform and fine particle size, and the viscosity has good stability over time. , it is possible to freely control physical properties such as fluidity and viscosity to target values, and easily obtain an oil-in-water emulsion.

The present invention will be explained in more detail below.

Structure of the Invention In the present invention, in the first step, an oil phase whose temperature is higher than the phase transition temperature of the primary highly concentrated oil-in-water emulsion and an aqueous phase are mixed so that the phase transition temperature of the primary highly concentrated oil-in-water emulsion is constant. A primary highly concentrated oil-in-water emulsion is obtained by mixing and emulsifying the mixture in proportions and in such a manner that the temperature of the primary highly concentrated oil-in-water emulsion to be produced is below its phase transition temperature.

In this case, since the phase transition temperature varies depending on the composition of the oil phase components, the temperatures of the oil phase and water phase are set appropriately accordingly, and the oil phase and water phase when the phase transition temperature of one emulsion is constant. Since the ratio between the oil phase and the water phase differs depending on the composition of the oil phase components, the mixing ratio between the oil phase and the aqueous phase is appropriately set accordingly.

Specifically, for example, the oil phase at a temperature higher than the phase transition temperature is adjusted so that the temperature of the primary high concentration emulsion is at the target temperature.
Add into the aqueous phase at 20°C. It is not necessary to add it gradually, but it can be added instantly. The amount of the aqueous phase used at this time is preferably the minimum amount at which the phase transition temperature of the emulsion obtained remains constant as the amount of water added to the oil phase is increased, as described above. If more than the minimum amount of water is used in the production of the primary high-concentration emulsion W/, the amount of water phase added in the second stage will be reduced, and there may be restrictions on the range of control over physical properties, production conditions, etc.

In the present invention, the above-mentioned second high concentration emulsion is used.

By adjusting the temperature of the emulsion and the strength of the shearing force during emulsification, the basic structure of hydration can be controlled, thereby controlling the desired physical properties such as stability, viscosity, and fluidity of the final emulsion. can be controlled. In addition,
The strength of the shearing force is usually 1.5 to 20 Wv/s, particularly preferably 4 to 15 rV/l.

Here, the oil phase used in the first step can be of a conventional composition, and can be prepared using, for example, the following components. That is, cationic surfactants, higher alcohols, emulsifiers, oily components, water, etc. Specifically,
Cationic surfactants such as stearyltrimethylammonium chloride, behenyltrimethy/I/7ammonium chloride, distearyldimethylammonium chloride, higher alcohols such as cetyl alcohol, stearyl alcohol, cetostearyl alcohol, behenyl alcohol, polyoxyethylene stearyl ether, holio Ethylene sorbitol tetraoleate, monopyroglutamic acid,
polyoxyethylene glycerin monoinostearate,
Emulsifiers such as polyoxyethylene, glyceryl tristearate, propylene glycol monostearate, sorbitan monostearate, diglycerin monostearate, sorbitan sesquiolate, silicones such as trimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, etc. These include oils and oily components of hydrocarbons such as fluid rough-in and squalane.

Further, the aqueous phase can also be of a normal composition, for example, using the following components, lIl! m can do. That is, water;
Low temperature stabilizers, nonionic surfactants, hydrophilic cationic surfactants, organic salts, inorganic salts, fragrances and pigments, etc.
Variants include water, and low-temperature stabilizers such as ethylene glycol, propylene glycol, ethylene glycol, and ethanol, /! Nonionic surfactants such as J oxyethylene nonylphenyl ether, I rio diethylene octylphenyl ether, glycerin fatty acid ester, hydrophilic cationic surfactants such as stearyltrimethylammonium chloride, and fi 4lumityltrimethylammonium chloride. organic salts such as citric acid, malic acid, and ethylenediaminetetraacetic acid (EDTA), and inorganic salts such as hydrochloric acid, sulfuric acid, sodium chloride, and sodium sulfate.

Note that the ratio of glycols or derivatives thereof to water as a low-temperature stabilizer added to the aqueous phase can be 20% (wt%, same hereinafter) or less.

Next, in the present invention, in the second step, the above-mentioned primary high concentration oil-in-water emulsion is mixed and emulsified with an aqueous phase having a temperature lower than the phase transition temperature of the primary high concentration oil-in-water emulsion. An oil-in-water emulsion is formed while cooling and dispersing the oil at the same time. In this case, the temperature of the aqueous phase used is not particularly limited, but if an aqueous phase at a temperature around room temperature is used, there is no need for cooling during or after the second stage of mixing, emulsification, and therefore it is suitable for industrialization. It's advantageous. Note that by adjusting the water phase temperature in this second stage and the shearing force t during emulsification, an emulsion with the desired emulsified state and physical properties can be obtained, but in this case, the strength of the shearing force is usually 1. .5 to 20 y@/m, particularly preferably 4 to 15 Vs. Furthermore, the same components as mentioned above can be used as the components constituting the aqueous phase.

In the method for producing an oil-in-water emulsion of the present invention, the proportions of the oil phase and water phase can be arbitrarily selected, and in this case, the water phase is divided and used in the first and second stages, respectively, as described above. As mentioned above, it is preferable to set the division ratio to the minimum amount such that the degree of phase transition of the emulsion is constant when the aqueous phase is added in the first stage. Generally, the aqueous phase is used in the first stage for 20 to 60 volumes of the total hydration amount.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the method for producing an oil-in-water emulsion according to the present invention has the following advantages.

■ Emul 7.7 It is possible to form extremely uniform and fine particle sizes, and it has excellent physical properties such as viscosity, and these physical properties have high stability over time, and the emulsified state is stable, resulting in the production of oil-type emulsions. be able to.

■ Since the generation of liquid crystals is not required, emulsification is possible in the range of ordinary emulsifier selection without using a surfactant with a special HLB value, and even nonionic surfactants that are soluble in the oil phase can be used. Since the surfactant can be used without problems and the surfactant is not limited in this way, the range of selective use of the surfactant is wide.

■ Addition of the water and oil phases can be done instantly, and an oil-in-water emulsion can be continuously produced to create the desired emulsion through a highly thixotropic highly concentrated emulsion. It is suitable for efficiently creating oil-in-water emulsions. can do.

■ Target physical properties of the emulsion (viscosity, fluidity, etc.)
The factors that control are the temperature and shear force of the primary high concentration emulsion during emulsification in the first stage where the basic structure of the high concentration emulsion can be freely changed, and the second stage where the dispersion state of the basic structure can be changed. Since there is a lot of shearing force during the emulsification step, it is possible to control stability and physical properties, which conventionally relied on a third component, for a wide range of purposes depending on the purpose without adding additives. Moreover, an oil-in-water emulsion having desired physical properties can be reliably prepared.

Next, examples and comparative examples will be shown to specifically explain the present invention.

[Examples 1 to 3. Comparative example 1] Stearyltrimethylammonium chloride 1.2%.

An oil phase containing 2.8% of motostearyl alcohol, 3.51% of globylene glycol/1.5% of lyoxyethylene glyceryl triisostearate and 0.21% of fluid 9 rough ins was maintained at 60°C, and the oil phase was heated at 60°C. A primary aqueous phase containing 0.2% diethylene alkylphenyl ether and a trace amount of pigment and adjusted to the temperature shown in Table 1 was subjected to a shearing force of 10-5 with a stirring blade. By supplying and emulsifying, a primary highly concentrated oil-in-water emulsion having a temperature shown in Table 1 was obtained as a first step.

As a second step, the first high concentration Aburaya emulsion in water obtained at the temperature shown in Table 1 obtained in the first step is treated with 0 fragrance.
．． 51 and was adjusted to a predetermined temperature of 25 to 35C, a secondary aqueous phase was instantly added, emulsified and dispersed under a shearing force of 7.5i, and the oil-in-water type of Examples 1 to 3 at 35C was I got an emulsion.

The total amount of water was divided into primary water phase: secondary water phase = 1:1. Further, the phase transition temperature of the -order highly concentrated coal oil-in-water emulsion in the first stage was 55°C, which is the same value as the phase transition temperature of the oil-in-water emulsion obtained in the second stage.

For comparison, a nine aqueous phase containing the total amount of water, 0.2% polyoxyethylene alkylphenyl ether and a trace amount of dye and adjusted to 30 °C without dividing the water into primary and secondary aqueous phases, By supplying the same oil phase at 60°C as above, an oil-in-water emulsion at 35°C of Comparative Example 1 was obtained.

Next, the viscosity and yield value t of the oil-in-water emulsions of Examples 1 to 3 and Comparative Example 1 were examined. The results are shown in Table 1. The yield value is a value measured using an Ill viscometer to determine the stress limit at which the emulsion begins to flow.

Table 1 *In the case where the aqueous phase was emulsified without being divided, the temperature of the total amount of hydration is shown.

[Example 4.5, Comparative Example 2.3] Example 4 was carried out in the same manner as in Example 2 except that the shearing force during the second stage of emulsification and dispersion was t-4, 5i and 10 ny'w. , 5 was obtained.

In addition, the shear force during emulsification and dispersion was set to 4.5 w- and 15 w-
Oil-in-water emulsions of Comparative Examples 2 and 3 were obtained in the same manner as in Comparative Example 1 except that /%'-.

Next, the physical properties of the emulsions of Examples 4 and 5 and Comparative Examples 2 and 3 were examined in the same manner as described above. The results are shown in Table 2.

Table 2 Same as Table 1 [Examples 6 to 8, Comparative Examples 4 and 5] Oil-in-water emulsions were produced by the following method using a continuous emulsifier in which two homomixers were connected in series.

Stearyldimethylammonium chloride 1.8%.

Stearyl alcohol 2.71 Silicone O, SS, polyoxyethylene alkali phenyl ether phosphoric acid 0.
4% and polyoxyethylene stearyl ether 0.8
Continuously feed the oil phase containing chlorine and maintained at 55°C and the primary aqueous phase containing 5.0% globylene glycol and a trace amount of pigment and adjusted to the temperature shown in Table 3 to a primary homomixer. A primary highly concentrated oil-in-water emulsion having a temperature shown in Table 3 is obtained by instantaneously emulsifying the sample at a shear force of 10 rtv'wg O. Next, a primary high-concentration oil-in-water emulsion t-I dioxyethylene nonylphenyl ether 0.3% and fragrance 0.3% at the temperature shown in Table 3 was prepared. ．．
A secondary aqueous phase containing 5% and adjusted to a predetermined temperature of 20 to 30°C is instantaneously emulsified and dispersed in a secondary homomixer having the shearing force shown in Table 3, and is continuously supplied with 35
The oil-in-water emulsions of Examples 6-8 at <RTIgt;C.

I got this.

The total amount of water was divided into primary aqueous phase: secondary aqueous phase = 1.5:IK and used. Further, the phase transition temperature of the primary highly concentrated oil-in-water emulsion in the first stage was 52°C, which is the same value as the phase transition temperature of the oil-in-water emulsion obtained in the second stage.

For comparison, a one-stage homomixer was used, without partitioning the water into primary and secondary aqueous phases, with an aqueous phase containing the total amount of water, propylene glycol 5.0 and a trace amount of dye and adjusted to 30C. , and an oil phase at 55°C with the same composition as above are continuously supplied to a homomixer and instantaneously emulsified and dispersed.
Oil-in-water emulsions of Comparative Examples 4 and 5 were obtained at 5°C.

Next, the physical properties of the emulsions of Examples 6 to 8 and Comparative Examples 4 and 5 were examined in the same manner as above. The results are shown in Table 3.

Table 3: Same as Table 1 **Clumps of oil phase components remain, resulting in insufficient emulsification Example 1~
Emulsion No. 8 was extremely stable, with its physical properties showing only a change within ±3% even after one year had passed.

Claims (1)

[Claims] 1. It consists of a first step of obtaining a primary highly concentrated oil-in-water emulsion and a second step of obtaining a desired oil-in-water emulsion from this primary highly concentrated oil-in-water emulsion. The oil phase, which has a higher temperature than the phase transition temperature of the type emulsion, and the aqueous phase are mixed at a ratio such that the phase transition temperature of the primary high concentration oil-in-water emulsion is constant, and the temperature of the primary high concentration oil-in-water emulsion to be produced is the same as that phase. After obtaining a primary high-concentration oil-in-water emulsion by mixing and emulsifying at a temperature below the transition temperature, in a second step, the primary high-concentration oil-in-water emulsion and the phase of the primary high-concentration oil-in-water emulsion are mixed. A method for producing an oil-in-water emulsion, characterized in that a desired oil-in-water emulsion is obtained by mixing and emulsifying an aqueous phase with a temperature lower than the transition temperature.