JP3740001B2 - Method for producing emulsion - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an emulsion in which fatty acid amide dispersed in water has a fine and uniform average particle size and good stability.
[0002]
[Prior art]
In general, an organic oil-in-water emulsion is obtained by using various surfactants or protective colloids as a dispersing agent, and pulverizing the oil phase in the aqueous phase by a mechanical force such as a colloid mill. High shear force using a wet pulverization method to obtain a type emulsion, or using various surfactants or water-soluble polymers as emulsifiers, and using an oil phase above the melting temperature of the oil phase and a homogenizer etc. There is known an emulsification method in which an oil-in-water emulsion is obtained by emulsifying and dispersing in (3) and then cooling it slowly or using a heat exchanger or the like.
[0003]
However, when fatty acid amide is used as the oil phase, the former method requires enormous processing time to obtain a stable dispersion having an average particle size of 1 micron or less when the concentration of fatty acid amide is 15% by weight or more. There is a problem that only an emulsion having poor stability can be obtained because the particle size distribution of dispersed particles is wide. On the other hand, even in the latter method, if the concentration of the fatty acid amide is 10% by weight or more, even if the emulsion is in a good emulsified state above the melting temperature of the fatty acid amide, the viscosity increases during cooling or the whole liquid gels or solidifies. As a result, a good emulsion cannot be obtained.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and provides an emulsion production method capable of obtaining a fatty acid amide emulsion in which the dispersed fatty acid amide has a fine and uniform average particle diameter and good stability. It is intended to do.
[0005]
[Means, actions and effects for solving the problems]
The invention of claim 1 made to solve the above object is a method for producing an emulsion, wherein a first step of emulsifying a fatty acid amide in water at a temperature equal to or higher than its melting temperature by applying a shearing force; It is characterized in that the second step of sequentially adding and mixing an emulsion having a temperature higher than the melting temperature generated in one step into an aqueous phase not higher than the melting temperature of the fatty acid amide is performed.
[0006]
According to the first aspect of the present invention, in the first step, an emulsion is produced in which fatty acid amide melted in high-temperature water is dispersed as fine droplets. Since this is thrown into and mixed with the aqueous phase below the melting temperature of the fatty acid amide in the second step, the temperature rapidly decreases. When the emulsion is rapidly cooled in this way, even when the concentration of the fatty acid amide in the emulsion is high, the cooled emulsion does not thicken, gel or solidify, and the fatty acid has a fine and uniform average particle size. A good emulsion in which the amide is dispersed can be obtained. Further, even when this emulsion is left for a long time, it does not cause aggregation / aggregation of particles or thickening of the emulsion, and is excellent in stability. Furthermore, in the second step, it is only necessary to mix the emulsion so that it is in a uniform state, and since a strong shearing force as in the first step is not required, the manufacturing apparatus and work are simple. As an aqueous phase used in the second step, water, an aqueous solution obtained by adding various stabilizers, surfactants and other auxiliary agents to water, an aqueous emulsion, and the like are possible.
[0007]
In the second step, the fatty acid amide emulsion already obtained can be used as the aqueous phase (invention of claim 2). In this case, if the fatty acid amide emulsion having the same concentration as the fatty acid amide emulsion obtained in the first step is used, the fatty acid amide emulsion having the same concentration is handled in the whole process, and the concentration management becomes simple.
[0008]
In the first step, water may be heated under a pressure equal to or higher than atmospheric pressure (invention of claim 3). Since water can be heated to 100 ° C. or higher under an atmosphere of atmospheric pressure or higher, even when the melting temperature of the fatty acid amide is 100 ° C. or higher, the water is set to 100 ° C. or higher and the fatty acid amide is heated to the melting temperature or higher. Because it can be.
[0009]
Furthermore, the temperature of the aqueous phase in the second step is preferably 30 ° C. or more lower than the melting temperature of the fatty acid amide (the invention of claim 4). When the high-temperature emulsion produced in the first step is rapidly cooled at a temperature difference of 30 ° C. or more, a good emulsion can be obtained more stably.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
According to the method for producing an emulsion of the present invention, as described above, first, in the first step, the fatty acid amide is emulsified in water by applying a shearing force at a temperature equal to or higher than its melting temperature. For example, the emulsification dispersion is performed by mixing the fatty acid amide, water, and the emulsifier at a temperature equal to or higher than the melting temperature of the fatty acid amide in an emulsification container, and applying a high shearing force with, for example, a high-pressure emulsifying disperser called a homogenizer. At this time, when the melting temperature of the fatty acid amide to be emulsified exceeds 100 ° C., the emulsified container is sealed and pressurized, and the temperature may be raised to 100 ° C. or higher. In this way, the melted fatty acid amide particles are dispersed in water with a fine and uniform particle size, and a good fatty acid amide emulsion is prepared.
[0011]
Then, in the second step, the high-temperature fatty acid amide emulsion obtained in the first step is gradually introduced into the aqueous phase maintained at a temperature lower than the melting temperature of the fatty acid amide, and uniformly mixed. In this way, the high-temperature emulsion charged into the aqueous phase is immediately and uniformly mixed while being rapidly cooled by being surrounded by the low-temperature aqueous phase. The temperature of the aqueous phase at this time is preferably kept at a low temperature of 30 ° C. or higher than the melting temperature of the fatty acid amide. As described above, when the fatty acid amide emulsion having a melting point higher than that of the fatty acid amide is rapidly discarded, the particles of the fatty acid amide dispersed in water do not aggregate and coagulate with each other, and the emulsion does not gel, and the average particle size is increased. A stable emulsion in which fine and uniform fatty acid amide particles of 1 μm or less are dispersed can be obtained.
[0012]
The concentration of the fatty acid amide emulsion may be adjusted by mixing and diluting the high-concentration emulsion prepared in the first step with water or an aqueous phase such as a low-concentration emulsion in the second step. In the process, an emulsion having a desired concentration may be prepared, and an emulsion having the same concentration prepared in advance may be put into an aqueous phase as a refrigerant. When the latter method is employed, the fatty acid amide emulsion having the same concentration is handled in the whole process, and the fatty acid amide emulsion having a desired concentration is continuously obtained, so that the productivity is good.
[0013]
In the present invention, the type of fatty acid amide dispersed in water may be those generally used. Specifically, saturated fatty acid monoamides such as lauric acid amide, palmitic acid amide, stearic acid amide, and behenic acid amide, unsaturated fatty acid monoamides such as oleic acid amide, erucic acid amide, and ricinoleic acid amide, N-stearyl stearin Substituted amides such as acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid amide, methylol stearic acid amide, methylol behen Methylolamides such as acid amides, methylenebisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bisisostearic acid amide, ethylene bishydroxystearate Acid amide, ethylene bisbehenic acid amide, hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bishydroxy stearic acid amide, N, N'-distearyl adipic acid amide, N, N'-distearyl Saturated fatty acid bisamides such as sebacic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, unsaturated aliphatic bisamides such as N, N'-dioleyl adipic acid amide, m-xylylene bisstearic acid amide Aromatic bisamides and the like. These fatty acid amides may be used alone or in combination of two or more.
[0014]
The present invention is particularly suitable when using saturated fatty acid monoamides such as lauric acid amide, palmitic acid amide, stearic acid amide, and behenic acid amide having a melting temperature in the range of about 85 ° C to 120 ° C. .
[0015]
According to the method for producing a fatty acid amide emulsion of the present invention, the average particle size of the fatty acid amide in the emulsion after cooling that is finally obtained is 1 μm or less.
[0016]
In the present invention, the concentration of the fatty acid amide emulsion is not particularly limited, but is preferably 10 to 40% by weight. If it is 10% by weight or less, a fatty acid amide emulsion can be obtained without cooling and thickening only by cooling the high temperature emulsion as it is. On the other hand, at a high concentration of 40% by weight or more, the high temperature emulsion does not diffuse sufficiently quickly into the cooling water phase, so that aggregates increase or the viscosity increases, and a good emulsion cannot be obtained.
[0017]
Moreover, you may mix additives, such as an emulsifier, an emulsion stabilizer, a rust preventive agent, a fungicide, and an antifoamer as needed.
The emulsifier is not particularly limited, and anionic, cationic, amphoteric and nonionic surfactants can be used.
[0018]
Anionic surfactants include fatty acids such as lauric acid, palmitic acid, stearic acid and oleic acid, higher alcohol sulfates, higher alkyl ether sulfates, sulfated fatty acid esters, sulfate esters such as sulfated olefins, and alkylbenzenes. Examples include sulfonic acid esters such as sulfonic acid, alkylnaphthalene sulfonic acid, paraffin sulfonic acid, sulfosuccinic acid diester, and phosphoric acid esters such as higher alcohol phosphoric acid esters and alkali metals, alkaline earth metals, or amines. It is done.
[0019]
Examples of cationic or amphoteric surfactants include quaternary ammonium salts such as alkyltrimethylammonium chloride salts and alkyldimethylbenzylammonium chloride salts, alkylpyridium chloride salts, and alkylbetaines.
[0020]
Nonionic surfactants include higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide. Polyethylene glycol types such as adducts, fat and oil ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, etc., or glycerol fatty acid esters, pentaerythritol fatty acid esters, sorbitol and sorbitan fatty acid esters, sucrose fatty acid esters, polyvalent Examples include polyhydric alcohol types such as alkyl ethers of alcohols and fatty acid amides of alkanolamines.
These surfactants are used alone or in combination of two or more.
[0021]
Examples of the emulsion stabilizer include polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, polyethylene oxide, polyacrylamide, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, starch, gelatin, and higher alcohol.
The mixing ratio of these additives is 0.1 to 100 parts by weight, preferably 3 to 50 parts by weight, based on 100 parts by weight of the fatty acid amide. If the amount is 0.1 parts by weight or less, it is difficult to obtain a stable emulsion, and the dispersed particles tend to be coarse. Further, even if 100 parts by weight or more is added, the dispersion stability is not improved and is useless.
[0023]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
<Example 1>
A pressure vessel was charged with 4000 g of palmitic acid amide, 294 g of lauric acid, 104 g of 25 wt% ammonia water, and 11800 g of water, heated to 120 ° C. under pressure, and then mixed with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Thereafter, homogenization was further performed with a high-pressure homogenizer (APV Gaulin, Inc.) under a homogeneous pressure of 20 MPa to obtain a high-temperature palmitic acid amide emulsion.
Next, 5000 g of 20 ° C. water as a refrigerant was placed in a refrigerant bath, and the above high temperature palmitic acid amide emulsion was gradually mixed into the refrigerant while cooling to 60 ° C. or lower. Thereafter, the mixture was further cooled to 30 ° C. to obtain an emulsion having a palmitic acid amide concentration of 20% by weight.
When the particle size of the obtained emulsion was measured with a laser scattering type particle size measuring device (LA920 manufactured by Horiba, Ltd.), the average particle size was 0.3 μm, and the viscosity at 20 ° C. was 12 mPa · s. It was. The particle size distribution is shown in FIG.
[0024]
<Example 2>
Into the pressure vessel, 4000 g of palmitic acid amide, 300 g of palmitic acid, 80 g of 25 wt% aqueous ammonia and 7400 g of water were added, and a high temperature palmitic acid amide emulsion was obtained in the same manner as in Example 1.
Next, 1774 g of water at 20 ° C. as a refrigerant is put in a refrigerant tank, and the above high temperature palmitic acid amide emulsion is gradually mixed in the refrigerant in the same manner as in Example 1 to obtain 30 wt% palmitic acid at 30 ° C. An amide emulsion was obtained.
The average particle diameter of the obtained emulsion was 0.6 μm, and the viscosity at 20 ° C. was 18 mPa · s.
[0025]
<Example 3>
A pressure vessel was charged with 3000 g of palmitic acid amide, 221 g of lauric acid, 76 g of 25 wt% aqueous ammonia and 12903 g of water, and a high temperature palmitic acid amide emulsion was obtained in the same manner as in Example 1.
Next, 20% by weight of palmitic acid amide emulsion obtained in Example 1 was used as a refrigerant instead of water, and the above-mentioned high-temperature palmitic acid amide emulsion was gradually added to the refrigerant in the same manner as in Example 1. Mixing gave a 20 wt% palmitic acid amide emulsion at 30 ° C.
The average particle diameter of the obtained emulsion was 0.4 μm, and the viscosity at 20 ° C. was 11 mPa · s.
[0026]
<Example 4>
The same procedure as in Example 1 was performed except that stearic acid amide was used instead of palmitic acid amide to obtain an emulsion containing 20% by weight of stearic acid amide.
The average particle diameter of the obtained emulsion was 0.3 μm, and the viscosity at 20 ° C. was 13 mPa · s.
[0027]
<Example 5>
The same procedure as in Example 1 was conducted except that behenic acid amide was used instead of palmitic acid amide to obtain an emulsion of 20% by weight of behenic acid amide.
The average particle diameter of the obtained emulsion was 0.8 μm, and the viscosity at 20 ° C. was 12 mPa · s.
[0028]
<Comparative Example 1>
When a high temperature emulsion was obtained in the same manner as in Example 1 and then cooled as it was, the whole liquid was solidified and a liquid emulsion could not be obtained.
[0029]
<Comparative Example 2>
When the high temperature emulsion obtained in the same manner as in Example 1 was extracted from the pressurized emulsification tank while cooling through a plate heat exchanger, the liquid thickened and became a paste, and a liquid emulsion could not be obtained. It was.
[0030]
<Comparative Example 3>
200 g of stearamide, 8 g of dioctyl sulfosuccinate soda salt and 798 g of water were mixed, and wet pulverization was performed in a batch type bead mill using 1.5 mm glass beads. The average particle size of the resulting dispersion was 2.5 μm. The particle size distribution is shown in FIG.
[0031]
As shown in the above Examples, the fatty acid amide emulsion prepared by the production method of the present invention has a fine average particle diameter of 1 μm or less of the fatty acid amide in which all of the emulsions are dispersed. Solidification did not occur. On the other hand, in the comparative example, the average particle diameter of the fatty acid amide was increased, or the emulsion was thickened or solidified, so that a fatty acid amide emulsion in a good state could not be obtained.
[Brief description of the drawings]
FIG. 1 is a graph showing the particle size distribution of Example 1. FIG. 2 is a graph showing the particle size distribution of Comparative Example 3.

Claims (4)

A first step in which a fatty acid amide is emulsified in water by applying a shearing force at a temperature equal to or higher than its melting temperature, and an emulsion having a temperature higher than the melting temperature generated in the first step is converted into an aqueous phase lower than the melting temperature of the fatty acid amide A method for producing an emulsion, comprising sequentially performing a second step of mixing and mixing in.   The method for producing an emulsion according to claim 1, wherein the aqueous phase in the second step is a fatty acid amide emulsion.   The method for producing an emulsion according to claim 1 or 2, wherein, in the first step, water is heated under a pressure equal to or higher than atmospheric pressure.   The method for producing an emulsion according to any one of claims 1 to 3, wherein the temperature of the aqueous phase in the second step is 30 ° C or more lower than the melting temperature of the fatty acid amide.

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