JP2009028635A - Method of manufacturing nano emulsion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing nano emulsion, which mono-disperses the size of dispersed particles of emulsion. <P>SOLUTION: In the manufacturing method of nano emulsion, via a fine structure having micro-pore through-holes with the distribution of the micro-pore diameter obtained by anodic oxidation of aluminum or an aluminum alloy within 3% of an average diameter, liquid serving as a dispersoid is disposed on one side and liquid serving as a disperse medium is disposed on the other side. The liquid serving as the dispersoid is passed through the micro-pores, and dispersed into the liquid serving as the disperse medium. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a nanoemulsion. The present invention also relates to a method for producing a nanoemulsion using a microstructure having micropore through holes.

  Conventionally, in various industrial fields, fluids having different properties have been mixed. As an example, there is a mixture of water and oil, which are fluids having different properties, and the oil is made into fine particles in water. There is so-called emulsification which is dispersed and emulsified. As a method for producing this emulsion, a liquid to be a dispersed phase (dispersoid) and an emulsifier such as a surfactant are added to a liquid to be a continuous phase (dispersion medium), and the resulting mixture is mixed with a machine such as a stirrer. There are a mechanical method of stirring and a membrane emulsification method in which a liquid to be a dispersed phase is pressed into a liquid to be a continuous phase through a microporous membrane. In the former method, it is difficult to freely change the particle size of the emulsion particles, which greatly affects the performance of the polymer by suspension polymerization. For example, as in Patent Documents 1 and 2, the latter method is generally used. Yes.

  However, emulsions produced by these methods are not uniform in size, and there is a demand for a method for producing an emulsion that can be monodispersed in size.

JP-A-11-333271 JP 2003-181262 A

  Therefore, an object of the present invention is to provide a production method capable of monodispersing the size of dispersed particles of an emulsion in a so-called membrane emulsification method.

  As a result of diligent studies to achieve the above object, the present inventor completed the present invention by emulsifying a film using an anodized film having micropores monodispersed in size.

That is, the present invention provides the following inventions.
(1) Through a microstructure having micropore through-holes in which the dispersion of micropore diameter obtained by anodizing aluminum or an aluminum alloy is within 3% of the average diameter,
Place the liquid that becomes the dispersoid on one side, the liquid that becomes the dispersion medium on the other side,
A method for producing a nanoemulsion, wherein the liquid as the dispersoid passes through the micropores and is dispersed in the liquid as a dispersion medium.
(2) The method according to (1), wherein the liquid as the dispersoid is pressurized and passed through the micropores.
(3) The production method of (1), wherein the liquid serving as the dispersion medium is decompressed and the liquid serving as the dispersoid is passed through the micropores.
(4) The method for producing a nanoemulsion according to any one of (1) to (3), wherein an aspect ratio of the micropores is an average value of 10 or more and less than 10,000.
(5) The method for producing a nanoemulsion according to any one of (1) to (4), wherein the degree of ordering defined by the following formula (1) is 50% or more for the micropore.
Ordering degree (%) = B / A × 100 (1)
In the above formula (1), A represents the total number of micropores in the measurement range. B is centered on the center of gravity of one micropore, and when a circle with the shortest radius inscribed in the edge of another micropore is drawn, the center of gravity of the micropores other than the one micropore is inside the circle. This represents the number in the measurement range of the one micropore to be included.
(6) through a microstructure having micropore through holes in which the dispersion of the micropore diameter obtained by anodizing aluminum or an aluminum alloy is within 3% of the average diameter;
A first fluid serving as a dispersoid on one side and a second fluid serving as a dispersion medium on the other side;
A hydrophilic fluid in which the first fluid passes through the micropore and is dispersed in the second fluid to produce a nanoemulsion, wherein the first fluid contains at least one particle of an inorganic compound A method for producing a nanoemulsion, wherein the second fluid is an organic solvent.
(7) Nanoemulsion manufactured with the manufacturing method in any one of said (1)-(6).

According to the present invention, a nanoemulsion having a monodispersed size produced by membrane emulsification can be obtained.
Here, the monodispersion is not limited, but the dispersion of the sphere diameter is preferably within 10% of the average diameter, more preferably within 8%, within 5%, and even more preferably within 3%.
Here, the nanoemulsion is not limited, but particles having an average particle diameter of 10 μm or less to 1 nm or more, or a dispersion medium in which these particles are dispersed are preferable.

The present invention is described in detail below.
The method for producing the nanoemulsion of the present invention comprises:
Through a microstructure having micropore through-holes in which the pore diameter dispersion obtained by anodizing aluminum or an aluminum alloy (hereinafter sometimes referred to as aluminum) is within 3% of the average diameter,
Place the liquid that becomes the dispersoid on one side, the liquid that becomes the dispersion medium on the other side,
This is a method for producing a nanoemulsion in which the liquid as the dispersoid passes through the micropores and is dispersed in the liquid as a dispersion medium.
Here, the liquid serving as the dispersoid may be pressurized and passed through the micropore, or the liquid serving as the dispersion medium may be decompressed and the liquid serving as the dispersoid passed through the micropore.

A micropore having a micropore diameter (hereinafter sometimes referred to as “pore diameter”) dispersion within 3% of the average diameter in the range of 1 μm ² is used. It is preferably within 2%. In addition, the average diameter and dispersion | distribution of a pore diameter can each be calculated | required by a following formula.
Average diameter: μ _x = (1 / n) ΣXi
Dispersion: σ ² = (1 / n) (ΣXi ² ) −μ _x ²
Dispersion / average diameter = σ / μ _x ≦ 0.03
Here Xi is the pore diameter of one micropore measured in the range of 1 [mu] m ^2, n is the number of micropores was measured in the range of 1 [mu] m ^2.

<Microstructure with micropore through hole>
<Aluminum substrate>
The aluminum substrate is not particularly limited. For example, a pure aluminum plate; an alloy plate containing aluminum as a main component and containing a small amount of foreign elements; a substrate obtained by depositing high-purity aluminum on low-purity aluminum (for example, recycled material); silicon Examples of the substrate include a substrate in which high purity aluminum is coated on the surface of a wafer, quartz, glass or the like by a method such as vapor deposition or sputtering; a resin substrate in which aluminum is laminated.

  Of the aluminum substrate, the surface on which the anodized film is provided by anodizing treatment preferably has an aluminum purity of 99.5% by mass or more, more preferably 99.9% by mass or more, and 99.99% by mass. % Or more is more preferable. When the aluminum purity is in the above range, the regularity of the micropore array is sufficient.

  The surface of the aluminum substrate is preferably subjected to degreasing and mirror finishing in advance.

  Moreover, it is preferable that the aluminum substrate is preliminarily subjected to heat treatment for the fine structure obtained by the present invention. The regularity of the pore arrangement is improved by the heat treatment.

<Heat treatment>
When heat treatment is performed, it is preferably performed at 200 to 350 ° C. for about 30 seconds to 2 minutes. Thereby, the regularity of the arrangement | sequence of the micropore produced | generated by the anodic oxidation process mentioned later improves.
The aluminum substrate after the heat treatment is preferably cooled rapidly. As a method of cooling, for example, a method of directly feeding into water or the like can be mentioned.

<Degreasing treatment>
Degreasing treatment uses acids, alkalis, organic solvents, etc. to dissolve and remove organic components such as dust, fat, and resin that adhere to the aluminum surface, and causes defects in each treatment described later due to the organic components. This is done for the purpose of preventing the occurrence of.
A conventionally known degreasing agent can be used for the degreasing treatment. Specifically, for example, various commercially available degreasing agents can be used by a predetermined method.

Especially, the following each method is illustrated suitably.
A method in which an organic solvent such as alcohol (for example, methanol), ketone, benzine, volatile oil or the like is brought into contact with the aluminum surface at room temperature (organic solvent method); a solution containing a surfactant such as soap or neutral detergent at a temperature from 80 to 80 A method in which the aluminum surface is contacted at a temperature up to ℃, and then washed with water (surfactant method); a sulfuric acid aqueous solution having a concentration of 10 to 200 g / L is brought into contact with the aluminum surface at a temperature from room temperature to 70 ° C for 30 to 80 seconds. Then, a method of washing with water; while a sodium hydroxide aqueous solution having a concentration of 5 to 20 g / L was brought into contact with the aluminum surface at room temperature for about 30 seconds, a direct current having a current density of 1 to 10 A / dm ² was passed with the aluminum surface as a cathode. And then neutralizing by contacting with a nitric acid aqueous solution having a concentration of 100 to 500 g / L; various known electrolytic solutions for anodizing treatment are usually used. In while in contact with the aluminum surface, the aluminum surface by applying a direct current of a current density of 1 to 10 A / dm ² in the cathode, or a method of electrolysis by passing an alternating current; the alkaline aqueous solution in the concentration of 10 to 200 g / L A method of bringing the aluminum surface into contact at 40 to 50 ° C. for 15 to 60 seconds, and then neutralizing by contacting with an aqueous nitric acid solution having a concentration of 100 to 500 g / L; a surfactant, water or the like was mixed with light oil or kerosene. A method in which the emulsion is brought into contact with the aluminum surface at a temperature from room temperature to 50 ° C. and then washed with water (emulsion degreasing method); a mixed solution of sodium carbonate, phosphates, surfactants, etc. is brought to a temperature from room temperature to 50 ° C. The aluminum surface is brought into contact with the aluminum surface for 30 to 180 seconds and then washed with water (phosphate method).

  The degreasing treatment is preferably a method in which the fat content on the aluminum surface can be removed while aluminum dissolution hardly occurs. In this respect, the organic solvent method, the surfactant method, the emulsion degreasing method, and the phosphate method are preferable.

<Mirror finish processing>
The mirror finishing process is performed to eliminate unevenness on the surface of the aluminum substrate and improve the uniformity and reproducibility of the particle forming process by an electrodeposition method or the like. Examples of the irregularities on the surface of the aluminum substrate include rolling stripes generated during rolling in the case where the aluminum substrate is manufactured through rolling.
In the present invention, the mirror finish is not particularly limited, and a conventionally known method can be used. Examples thereof include mechanical polishing, chemical polishing, and electrolytic polishing.

  Examples of the mechanical polishing include a method of polishing with various commercially available polishing cloths, and a method of combining various commercially available abrasives (for example, diamond, alumina) and a buff. Specifically, a method in which the method using an abrasive is performed by changing the abrasive used from coarse particles to fine particles over time is preferably exemplified. In this case, the final polishing agent is preferably # 1500. Thereby, the glossiness can be 50% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 50% or more).

As chemical polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. Various methods described in 164 to 165 may be mentioned.
Further, phosphoric acid - nitric acid method, Alupol I method, Alupol V method, Alcoa R5 _{method, H 3 PO 4 -CH 3 COOH} -Cu _{method, H 3 PO 4 -HNO 3 -CH} 3 COOH method are preferable. Among these, the phosphoric acid-nitric acid method, the H ₃ PO ₄ —CH ₃ COOH—Cu method, and the H ₃ PO ₄ —HNO ₃ —CH ₃ COOH method are preferable.
By chemical polishing, the glossiness can be made 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

As electrolytic polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. Various methods described in 164 to 165 may be mentioned.
Moreover, the method described in US Pat. No. 2,708,655 is preferable.
“Practical Surface Technology”, vol. 33, no. 3, 1986, p. The method described in 32-38 is also preferably exemplified.
By electropolishing, the gloss can be 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

  These methods can be used in appropriate combination. For example, a method of using an abrasive is preferably performed by changing the abrasive to be used from coarse particles to fine particles over time, and then performing electrolytic polishing.

By mirror finishing, for example, a surface having an average surface roughness R _a of 0.1 μm or less and a glossiness of 50% or more can be obtained. The average surface roughness _Ra is preferably 0.03 μm or less, and more preferably 0.02 μm or less. Further, the glossiness is preferably 70% or more, and more preferably 80% or more.
The glossiness is a regular reflectance obtained in accordance with JIS Z8741-1997 “Method 3 60 ° Specular Gloss” in the direction perpendicular to the rolling direction. Specifically, using a variable angle gloss meter (for example, VG-1D, manufactured by Nippon Denshoku Industries Co., Ltd.), when the regular reflectance is 70% or less, the incident reflection angle is 60 degrees and the regular reflectance is 70%. In the case of exceeding, the incident / reflection angle is 20 degrees.

<(A) Micropore formation treatment by anodic oxidation>
In the treatment (A), an aluminum substrate is anodized to form an oxide film having micropores on the surface of the aluminum substrate.
As the anodizing treatment, a conventionally known method can be used. Specifically, it is preferable to use the self-ordering method described later.
The self-ordering method is a method of improving the regularity by utilizing the property that the micropores of the anodized film are regularly arranged and removing the factors that disturb the regular arrangement. Specifically, high-purity aluminum is used, and an anodized film is formed at a low speed over a long period of time (for example, several hours to several tens of hours) at a voltage according to the type of the electrolytic solution.
In this method, since the average diameter of the micropores formed by anodization depends on the voltage, a desired pore diameter can be obtained to some extent by controlling the voltage.
In order to form the micropores by the self-ordering method, an anodizing process described later may be performed. Preferably, an anodizing process, a film removal process, and a re-anodizing process described later are performed in this order.

<Anodizing treatment>
The average flow rate during the anodizing treatment is preferably 0.5 to 20.0 m / min, more preferably 1.0 to 15.0 m / min, and 2.0 to 10.0 m / min. More preferably, it is min. By performing anodizing treatment at a flow rate in the above range, micropores having uniform and high regularity can be obtained.
Moreover, the method of flowing the electrolytic solution under the above-mentioned conditions is not particularly limited, but, for example, a method using a general stirring device such as a stirrer is used. It is preferable to use a stirrer that can control the stirring speed with a digital display because the average flow rate can be controlled. As such a stirring apparatus, for example, magnetic stirrer HS-50D manufactured by AS ONE can be mentioned.

  For the anodizing treatment, for example, a method of energizing an aluminum substrate as an anode in a solution having an acid concentration of 0.01 to 5 mol / L can be used. The solution used for the anodizing treatment is preferably an acid solution, more preferably sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid, etc., among which sulfuric acid, phosphoric acid, Oxalic acid is particularly preferred. These acids can be used alone or in combination of two or more.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined in general. In general, however, the electrolyte concentration is 0.01 to 5 mol / L, the solution temperature is -10 to 30 ° C., and the current density. 0.01 to 20 A / dm ² , voltage 3 to 300 V, electrolysis time 0.5 to 30 hours are preferable, electrolyte concentration 0.05 to 3 mol / L, solution temperature −5 to 25 ° C., current density 0 0.05 to 15 A / dm ² , voltage 5 to 250 V, electrolysis time 1 to 25 hours is more preferable, electrolyte concentration 0.1 to 1 mol / L, solution temperature 0 to 20 ° C., current density 0.1 to More preferably, it is 10 A / dm ² , a voltage of 10 to 200 V, and an electrolysis time of 2 to 20 hours.

  The treatment time for the anodizing treatment is preferably 0.5 minutes to 16 hours, more preferably 1 minute to 12 hours, and further preferably 2 minutes to 8 hours.

  The anodizing treatment can be performed by changing the voltage intermittently or continuously in addition to being performed under a constant voltage. In this case, it is preferable to decrease the voltage sequentially. This makes it possible to reduce the resistance of the anodized film, and fine micropores are formed in the anodized film, which is preferable in terms of improving uniformity, particularly when sealing treatment is performed by electrodeposition. .

The thickness of the anodized film is preferably 0.1 to 2000 μm, more preferably 1 to 1000 μm, and still more preferably 10 to 500 μm.
The average pore density is preferably from 50 to 1,500 / [mu] m ^2.
The pore diameter of the micropore is preferably 0.001 to 0.5 μm.

A micropore having a pore diameter dispersion within 3% of the average diameter in the range of 1 μm ² is used. It is preferably within 2%. In addition, the average diameter and dispersion | distribution of a pore diameter can each be calculated | required by a following formula.
Average diameter: μ _x = (1 / n) ΣXi
Dispersion: σ ² = (1 / n) (ΣXi ² ) −μ _x ²
Dispersion / average diameter = σ / μ _x ≦ 0.03
Here Xi is the pore diameter of one micropore measured in the range of 1 [mu] m ^2, n is the number of micropores was measured in the range of 1 [mu] m ^2.

  The area ratio occupied by the micropores is preferably 20 to 50%. The area ratio occupied by the micropores is defined by the ratio of the total area of the micropore openings to the area of the aluminum surface.

<Film removal treatment>
After forming the anodized film on the surface of the aluminum substrate by anodizing treatment, a treatment for heating the anodized film described later may be performed immediately. However, after the anodizing treatment, film removal treatment and re-anodizing treatment are performed. After performing in this order, it is preferable to perform the process which heats an anodic oxide film.
In the film removal process, the anodized film formed on the surface of the aluminum substrate by the anodizing process is dissolved and removed.

  Since the anodic oxide film is more regular as it gets closer to the aluminum substrate, the anodic oxide film is removed once by this film removal treatment, and the bottom portion of the anodic oxide film remaining on the surface of the aluminum substrate is made the surface. It can be exposed to obtain regular depressions. Therefore, in the film removal treatment, aluminum is not dissolved, but only the anodized film made of alumina (aluminum oxide) is dissolved.

  Alumina solution includes chromium compound, nitric acid, phosphoric acid, zirconium compound, titanium compound, lithium salt, cerium salt, magnesium salt, sodium fluorosilicate, zinc fluoride, manganese compound, molybdenum compound, magnesium compound, barium compound and An aqueous solution containing at least one selected from the group consisting of simple halogens is preferred.

Specific examples of the chromium compound include chromium (III) oxide and anhydrous chromium (VI) acid.
Examples of the zirconium-based compound include zircon ammonium fluoride, zirconium fluoride, and zirconium chloride.
Examples of the titanium compound include titanium oxide and titanium sulfide.
Examples of the lithium salt include lithium fluoride and lithium chloride.
Examples of the cerium salt include cerium fluoride and cerium chloride.
Examples of the magnesium salt include magnesium sulfide.
Examples of the manganese compound include sodium permanganate and calcium permanganate.
Examples of the molybdenum compound include sodium molybdate.
Examples of magnesium compounds include magnesium fluoride pentahydrate.
Examples of barium compounds include barium oxide, barium acetate, barium carbonate, barium chlorate, barium chloride, barium fluoride, barium iodide, barium lactate, barium oxalate, barium perchlorate, barium selenate, selenite. Examples thereof include barium, barium stearate, barium sulfite, barium titanate, barium hydroxide, barium nitrate, and hydrates thereof. Among the barium compounds, barium oxide, barium acetate, and barium carbonate are preferable, and barium oxide is particularly preferable.
Examples of halogen alone include chlorine, fluorine, and bromine.

Among them, the alumina solution is preferably an aqueous solution containing an acid. Examples of the acid include sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like, and a mixture of two or more acids may be used.
The acid concentration is preferably 0.01 mol / L or more, more preferably 0.05 mol / L or more, and still more preferably 0.1 mol / L or more. There is no particular upper limit, but generally it is preferably 10 mol / L or less, more preferably 5 mol / L or less. An unnecessarily high concentration is not economical, and if it is higher, the aluminum substrate may be dissolved.

  The alumina solution is preferably −10 ° C. or higher, more preferably −5 ° C. or higher, and still more preferably 0 ° C. or higher. In addition, since the starting point of ordering will be destroyed and disturbed if it processes using the boiling alumina solution, it is preferable to use it without boiling.

  The alumina solution dissolves alumina and does not dissolve aluminum. Here, the alumina solution may not dissolve aluminum substantially or may dissolve it slightly.

  The film removal treatment is performed by bringing the aluminum substrate on which the anodized film is formed into contact with the above-described alumina solution. The method of making it contact is not specifically limited, For example, the immersion method and the spray method are mentioned. Of these, the dipping method is preferred.

The dipping method is a treatment in which an aluminum substrate on which an anodized film is formed is dipped in the above-described alumina solution. Stirring during the dipping process is preferable because a uniform process is performed.
The dipping treatment time is preferably 10 minutes or longer, more preferably 1 hour or longer, and further preferably 3 hours or longer and 5 hours or longer.

  In the film removal treatment, the anodized film formed in the step (A) is partially dissolved using acid or alkali. The partial dissolution of the anodic oxide film does not completely dissolve the anodic oxide film formed in the step (A), but the micropores are formed on the aluminum substrate 12a as shown in FIG. This means that the surface of the anodized film 14a shown in FIG. 1A and the inside of the micropore 16a are partially dissolved so that the anodized film 14b having 16b remains.

  Here, the dissolution amount of the anodized film is preferably 0.001 to 50% by mass of the entire anodized film, more preferably 0.005 to 30% by mass, and 0.01 to 15% by mass. More preferably. Within the above range, the irregular arrangement of the surface of the anodized film can be dissolved to increase the regularity of the arrangement of the micropores, and the anodized film can remain on the bottom of the micropores. Thus, the starting point of the re-anodizing treatment described below can be left.

<Re-anodizing treatment>
After removing the anodized film by removing the film to form regular depressions on the surface of the aluminum substrate, anodizing is performed again to form an anodized film with a higher degree of ordering of micropores. be able to.
For the anodizing treatment, a conventionally known method can be used, but it is preferably performed under the same conditions as the above-described <anodic oxidation treatment>.
Also, a method of repeatedly turning on and off the current intermittently while keeping the DC voltage constant, and a method of repeatedly turning on and off the current while intermittently changing the DC voltage can be suitably used. According to these methods, fine micropores are generated in the anodic oxide film, which is preferable in that uniformity is improved particularly when sealing treatment is performed by electrodeposition.

When the anodized film is formed at a low temperature, the arrangement of micropores becomes regular and the pore diameter becomes uniform.
On the other hand, by performing the anodizing treatment at a relatively high temperature, the arrangement of the micropores can be disturbed, and the pore diameter variation can be made within a predetermined range. Also, the pore diameter variation can be controlled by the processing time.

  As shown in FIG. 1C, the oxidation reaction of the aluminum substrate 12a shown in FIG. 1B proceeds by the re-anodizing treatment, and on the aluminum substrate 12b in the depth direction from the micropore 16b. An anodized film 14c having the grown micropores 16c is formed. The above steps may be repeated a plurality of times such as anodizing treatment-defilming treatment-reanodizing treatment-defilming treatment-reanodizing treatment.

The thickness of the anodized film is preferably from 0.1 to 2000 μm, preferably from 1 to 1000 μm, and more preferably from 10 to 500 μm.
The pore diameter of the micropore is preferably 0.001 to 0.5 μm.
As a result, the aspect ratio of the micropore is preferably 10 or more and less than 10,000, preferably 25 or more and less than 5000, and more preferably 50 or more and less than 1000. In the nanoemulsion method, the pressure applied to the liquid phase is transmitted to the film, so if the aspect ratio is below the above range, it may break, and if the aspect ratio is above the above range, the liquid phase is microscopic. It tends to stay in the pores, which is not preferable.
The average pore density is preferably from 50 to 1,500 / [mu] m ^2.

<(B). Heat treatment of the anodized film formed in (A)>
The anodized film formed by the above procedure is heat-treated at a temperature of 50 ° C. or higher and at a load of 0.5 g / cm ² for at least 10 minutes. In order to perform this heat treatment, the aluminum substrate on which the anodized film is formed may be heated under the above conditions.
As a result of intensive studies, the inventors of the present invention have found that when the anodic oxide film is heat-treated, the flatness of the anodic oxide film is fixed and baked while being sandwiched between plates having a flat surface according to the desired flatness. Found a significant improvement.
Further, it is presumed that heating the anodized film itself has the effect of removing the acid ions remaining on the surface of the anodized film and in the micropores along with the evaporation of water remaining in the film. As a result, the acid resistance and alkali resistance of the anodized film are improved.

When the load is less than 0.5 g / cm ² , the flatness cannot be sufficiently improved.
The weight is preferably 1.0 g / cm ² or more, more preferably 5.0 g / cm ² or more, and still more preferably 10.0 g / cm ² or more. Although depending on the thickness of the oxide film, if the weight exceeds 500 g / cm ² , the film itself is damaged, which is not preferable.

On the other hand, if the heating temperature is less than 50 ° C., the effect of removing acid ions remaining on the surface of the anodized film or in the micropores cannot be sufficiently exhibited.
The heating temperature is preferably 150 ° C. or higher, more preferably 200 ° C. or higher, and further preferably 400 ° C. or higher.
However, if the heating temperature is too high, the aluminum substrate on which the anodized film is formed is deformed by heat and may be damaged between the fixing plates. Therefore, the heating temperature is preferably 800 ° C. or lower.

If the heating time is less than 10 minutes, the flatness of the oxide film and the effect of removing the acid ions remaining on the surface of the anodic oxide film and in the micropores cannot be exhibited sufficiently.
The heating time is preferably 15 minutes or longer, more preferably 30 hours or longer, and even more preferably 1 hour or longer.
Even when heated for 10 hours or more, the flatness does not improve, and it no longer contributes to the action of removing acid ions remaining on the surface of the anodized film or micropores, which is preferable from the viewpoint of yield and energy efficiency. Absent.

  The anodized film after heating is preferably cooled rapidly. As a method for cooling, for example, a method in which the fine structure is directly poured into water or the like can be mentioned.

When the microstructure is used in the method for producing an emulsion of the present invention, it is necessary that the micropores penetrate, that is, the micropores are through holes.
In the case of obtaining a microstructure having micropore through-holes, the method for producing a microstructure of the present invention further includes (C) a treatment for removing aluminum from the oxide film obtained in the treatment (A), and ( D) Treatment for penetrating the micropores of the oxide film obtained in the above treatment (A),
Are applied in this order, and then the treatment (B) is preferably performed.

<(C) Aluminum removal treatment>
FIG. 1A is a partial cross-sectional view showing a state after the processing (A). As shown in FIG. 1A, an anodic oxide film 14a having micropores 16a is formed on the surface of the aluminum substrate 12a.
In the aluminum removal treatment, the aluminum substrates 12a and 12b are dissolved and removed from the state shown in FIGS. FIG. 2 is a partial cross-sectional view showing a state after the main processing, and shows a fine structure made of an anodic oxide film 14d having micropores 16d.
Therefore, in the aluminum removal treatment, a treatment solution that does not dissolve alumina but dissolves aluminum is used.

The treatment liquid is not particularly limited as long as it does not dissolve alumina and dissolves aluminum. For example, an aqueous solution such as mercury chloride, bromine / methanol mixture, bromine / ethanol mixture, aqua regia, hydrochloric acid / copper chloride mixture, etc. Etc.
As a density | concentration, 0.01-10 mol / L is preferable and 0.05-5 mol / L is more preferable.
As processing temperature, -10 degreeC-80 degreeC are preferable, and 0 degreeC-60 degreeC is preferable.

  The aluminum removal treatment is performed by contacting with the treatment liquid described above. The method of making it contact is not specifically limited, For example, the immersion method and the spray method are mentioned. Of these, the dipping method is preferred. The contact time at this time is preferably 10 seconds to 5 hours, and more preferably 1 minute to 3 hours.

  The film thickness of the anodized film after the aluminum removal treatment is preferably 1 to 1000 μm, and more preferably 10 to 500 μm.

  After the aluminum removal treatment, the anodized film 14d is washed with water before the treatment (D) described later. In order to suppress a change in the pore diameter of the micropore 16d due to hydration, the water washing treatment is preferably performed at 30 ° C. or lower.

<(D) Micropore penetration processing>
In the micropore penetration process, the anodic oxide film 14d having the micropores 16d shown in FIG. 2 is immersed in an acid aqueous solution or an alkaline aqueous solution, whereby the anodic oxide film 14d is partially dissolved. Thereby, the anodic oxide film 14d at the bottom of the micropore 16d is removed, and the micropore 16d penetrates (the micropore through hole 16 is formed). FIG. 3 is a partial cross-sectional perspective view showing a state after the micropore penetrating treatment, and shows a fine structure made of the anodic oxide film 14 having the micropore through hole 16.
In FIG. 3, all the micropores existing in the anodic oxide film 14 are the micropore through holes 16, but all the micropores existing in the anodic oxide film may not penetrate through the treatment (D). . However, when the microstructure of the present invention is used as a porous alumina membrane filter, 70% or more of the micropores present in the anodized film are preferably penetrated by the treatment (D).

When an acid aqueous solution is used for the micropore penetration treatment, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or a mixture thereof. The concentration of the acid aqueous solution is preferably 1 to 10% by mass. The temperature of the acid aqueous solution is preferably 25 to 40 ° C.
When an alkaline aqueous solution is used for the micropore penetration treatment, it is preferable to use an aqueous solution of at least one alkali selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. The temperature of the alkaline aqueous solution is preferably 20 to 35 ° C.
Specifically, for example, 50 g / L, 40 ° C. phosphoric acid aqueous solution, 0.5 g / L, 30 ° C. sodium hydroxide aqueous solution or 0.5 g / L, 30 ° C. potassium hydroxide aqueous solution is preferably used. .
The immersion time in the acid aqueous solution or alkali aqueous solution is preferably 8 to 120 minutes, more preferably 10 to 90 minutes, and still more preferably 15 to 60 minutes.

  The film thickness of the anodized film after the micropore penetration treatment is preferably 1-1000 μm, and more preferably 10-500 μm.

  After the micropore penetration treatment, the anodic oxide film 14 is washed with water before the treatment (B). In order to suppress a change in the pore diameter of the micropore through hole 16 due to hydration, the water washing treatment is preferably performed at 30 ° C. or lower.

By subjecting the aluminum substrate to at least the treatments (A) and (B) in this order, preferably, subjecting the aluminum substrate to the treatments (A), (C), (D) and (B) in this order. In the obtained microstructure of the present invention, the film is deformed into a flat shape by heating the anodized film while applying a weight in the treatment (B). The flatness is preferably a warp of 20 μm or less per 10 mm length at any location in the film, more preferably 15 μm or less, and even more preferably 10 μm or less.
The magnitude of warpage in the anodized film can be measured by, for example, a surface roughness meter or a micromap meter.

In the microstructure of the present invention, the degree of ordering defined by the following formula (1) is preferably 50% or more, more preferably 70% or more, and more preferably 80% or more for the micropores. Is more preferable.
Ordering degree (%) = B / A × 100 (1)
In the above formula (1), A represents the total number of micropores in the measurement range. B is centered on the center of gravity of one micropore, and when a circle with the shortest radius inscribed in the edge of another micropore is drawn, the center of gravity of the micropores other than the one micropore is inside the circle. This represents the number in the measurement range of the one micropore to be included.

FIG. 4 is an explanatory diagram of a method for calculating the degree of ordering of pores. The above formula (1) will be described more specifically with reference to FIG.
A micropore 1 shown in FIG. 4 (A) is a circle 3 (with the shortest radius that is centered on the center of gravity of the micropore 1 (the center of a plane-like substantially circular equivalent circle) and inscribed in the edge of another micropore. In the case of drawing inscribed in the micropore 2), the center of gravity of the micropores other than the micropore 1 is included in the circle 3. Therefore, the micropore 1 is included in B.
The micropore 4 shown in FIG. 4B draws a circle 6 (inscribed in the micropore 5) having the shortest radius and centering on the center of gravity of the micropore 4 and inscribed in the edge of another micropore. In this case, the center of gravity of the micropores other than the micropores 4 is included inside the circle 6. Therefore, the micropore 4 is not included in B. Further, the micropore 7 shown in FIG. 1B is centered on the center of gravity of the micropore 7 and has the shortest radius 9 inscribed in the edge of another micropore (inscribed in the micropore 8). Is drawn, the circle 9 includes seven centroids of micropores other than the micropore 7. Therefore, the micropore 7 is not included in B.

<Hydrophilic treatment>
The fine structure may form a protective film on the surface and / or inside the micropore, and is an inorganic protective film containing at least one selected from the group consisting of Zr element and Si element, or a water-insoluble polymer An organic protective film containing Of these, hydrophilic treatment for forming an inorganic protective film is preferred.

<Inorganic protective film>
The formation of the protective film containing the Zr element is not particularly limited, but, for example, a method in which the protective film is directly immersed in an aqueous solution in which a zirconium compound is dissolved is generally used. From the viewpoint of the robustness / stability of the protective film It is preferable to use an aqueous solution in which a phosphorus compound is dissolved together.

  Zirconium compounds include zirconium, fluoride fluoride, sodium fluoride zirconate, calcium fluoride zirconate, zirconium fluoride, zirconium chloride, zirconium oxychloride, zirconium oxynitrate, zirconium sulfate, zirconium ethoxide, zirconium propoxide, zirconium Butoxide, zirconium acetylacetonate, tetrachlorobis (tetrahydrofuran) zirconium, bis (methylcyclopentadienyl) zirconium dichloride, dicyclopentadienylzirconium dichloride, ethylenebis (indenyl) zirconium (IV) dichloride, etc. can be used. Sodium fluorinated zirconate is preferred. Moreover, as a density | concentration, 0.01-10 mass% is preferable from a viewpoint of the uniformity of a protective film thickness, and 0.05-5 mass% is more preferable.

  As the phosphorus compound, phosphoric acid, sodium phosphate, calcium phosphate, sodium hydrogen phosphate, calcium hydrogen phosphate and the like can be used, and sodium hydrogen phosphate is particularly preferable. Moreover, as a density | concentration, 0.1-20 mass% is preferable from a viewpoint of the uniformity of a protective film thickness, and 0.5-10 mass% is more preferable.

Moreover, since the function which prevents the hydration of the anodic oxide film of the protective film formed improves, it is preferable to include tannic acid in the aqueous solution in which the zirconium compound is dissolved in the immersion treatment. In this case, the concentration of tannic acid in the aqueous solution is preferably 0.05 to 10% by mass, and more preferably 0.1 to 5% by mass.
Moreover, as processing temperature, 0-120 degreeC is preferable and 20-100 degreeC is more preferable.

The formation of the protective film containing Si element is not particularly limited, but, for example, a method in which the protective film is directly immersed in an aqueous solution in which an alkali metal silicate is dissolved is generally used.
The aqueous solution of the alkali metal silicate is composed of a ratio of silicon oxide SiO ₂ and alkali metal oxide M ₂ O (generally expressed as a molar ratio of [SiO ₂ ] / [M ₂ O]) and concentration. It is possible to adjust the protective film thickness. Here, as M, sodium and potassium are particularly preferably used.
As a molar ratio, [SiO ₂ ] / [M ₂ O] is preferably 0.1 to 5.0, and more preferably 0.5 to 3.0. The content of SiO _2, preferably from 0.1 to 20 mass%, 0.5 to 10 mass% is more preferable.

Said fine structure is suitable as a porous alumina membrane filter besides the manufacturing method of the nanoemulsion of this invention.
In addition, the fine structure can also carry an organic compound, an inorganic compound, metal fine particles, or the like in the micropores of the anodized film depending on the application.

<Liquid as dispersion and liquid as dispersion medium>
In the production method of the present invention, a liquid that becomes a dispersoid on one side (hereinafter sometimes referred to as a first fluid) and a dispersion medium on the other side through the microstructure having the micropore through holes described above. A liquid (hereinafter sometimes referred to as a first fluid) is disposed. The first fluid and the second fluid are not particularly limited. An emulsion is a colloidal dispersion system in which one is dispersed in the form of fine particles in the other phase between two liquid phases that do not mix with each other. The emulsion includes a water-oil emulsion (W / O emulsion) when the dispersion medium is water (hydrophilic liquid) and an oil-water emulsion (O / water emulsion when the dispersion medium is oil (an organic liquid insoluble in water)). W type emulsion). In the case of producing a W / O type emulsion, the first fluid that is a dispersoid is an organic liquid, and the second fluid that is a dispersion medium is a hydrophilic fluid. In the case of an O / W emulsion, the dispersoid and the dispersion medium may be reversed.

  The emulsion may be, for example, cream, milk, butter, lubricating oil dispersed in water, a pigment dispersed in water, or an aqueous dispersion suspension of a polymeric substance. In accordance with the production of such various emulsions, the present invention selects the dispersoid and the dispersion medium as the first fluid and the second fluid, respectively.

<First fluid>
Preferred first fluids for use in the present invention include alkali metal silicates, carbonates, phosphates, sulfates, alkaline earth metal halides and copper and iron group element sulfates, hydrochlorides, A hydrophilic fluid containing at least one particle of an inorganic compound selected from the group consisting of nitrates, such as water or alcohol, is preferred. The concentration of the inorganic compound particles is preferably 0.3 mol / L or more and a saturated concentration.

<Second fluid>
When the hydrophilic fluid containing the above-mentioned inorganic compound particles is the first fluid, the second fluid is preferably an organic solvent, and what is used as the type thereof is not particularly limited, It is preferable to use an organic solvent having a solubility in water of 5% or less. Specific examples are listed below.

  Aliphatic hydrocarbons; n-hexane, isohexane, n-heptane, isoheptane, n-octene, isooctene, gasoline, petroleum ether, kerosene, benzine, mineral spirit, and the like.

  Cycloaliphatic hydrocarbons; cyclopentane, cyclohexane, cyclohexene, cyclononane, etc.

  Aromatic hydrocarbons: benzene, toluene, xylene, ethylbenzene, propylbenzene, cumene, mesitylene, tetralin, styrene, etc.

  Ethers; propyl ether, isopropyl ether, etc.

  Halogenated hydrocarbons; methylene chloride, chloroform, ethylene chloride, trichloroethane, trichloroethylene, etc.

  Esters: ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, butyl lactate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate , Ethyl butyrate, butyl butyrate and so on.

  The said organic solvent may be used independently and may use 2 or more types together.

<Surfactant>
When a surfactant is blended in the organic solvent, the surfactant is not particularly limited except that it is nonionic. Preferred specific examples thereof are listed below. The surfactant acts as an emulsifier for the emulsion.

  Polyoxyethylene sorbitan aliphatic ester type; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxy Ethylene sorbitan trioleate, polyoxyethylene sorbitan stearate, etc.

  Polyoxyethylene higher alcohol ether type; polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether and the like.

  Polyoxyethylene aliphatic ester type; polyoxyethylene glycol monolaurate, polyoxyethylene glycol monostearate, polyoxyethylene glycol stearate, polyoxyethylene glycol monooleate and the like.

  Glycerin aliphatic ester type; stearic acid monoglyceride, oleic acid monoglyceride and the like.

  Polyoxyethylene sorbitol aliphatic ester type; tetraoleic acid polyoxyethylene sorbit, etc.

  The said surfactant may be used independently and may use 2 or more types together. As the usage-amount of surfactant, about 10 weight% or less of the organic solvent to be used is preferable, and about 0.1 to 3 weight% is further more preferable.

<Process for dispersing a liquid as a dispersoid in a liquid as a dispersion medium through the micropore>
A known membrane emulsification apparatus can be used for the step of dispersing the liquid as the dispersoid into the liquid as the dispersion medium through the micropores. The microstructure used in the present invention is used as a film. A method of pressurizing the liquid as the dispersoid and passing it through the micropores may be used, but the liquid as the dispersion medium may be depressurized and the liquid as the dispersoid may be passed through the micropores. You may use together. A known device can be used as the pressurization and decompression device. In the case of pressurization, 0.01 to 10 MPa is preferable. This is because within this range, the dispersoid can pass through the microstructure used in the present invention stably.
The step of dispersing may be performed at normal temperature, but may be heated. In that case, the temperature is preferably 30 to 200 ° C, more preferably 40 to 100 ° C. The reason for this is presumed to be that the surface energy of the dispersoid is improved by heating and the dispersibility is improved.
Either the first fluid or the second fluid may be stirred. The stirring may be any of mechanical stirring, ultrasonic stirring, magnetic stirring, gas insertion stirring and the like.

<Emulsion precipitation and shape correction>
As a method for producing microspheres from a large number of emulsion particles formed in an organic solvent, a precipitating agent capable of precipitating the emulsion particles in an organic solvent containing the emulsion particles is added, and precipitation that is a precursor of the particles is performed. A method for obtaining particles by baking the precipitate, and forming a sol containing the raw material before polymerization into a sol emulsion particle in an organic solvent, and then promoting the polymerization reaction to increase the emulsion particle of the sol There is a method of gelling and precipitating, and drying and baking the precipitate. Compared to the former method, the latter method has the advantages that the obtained inorganic uniform microspheres are less likely to contain impurities and that the pore diameter of the microspheres can be easily controlled. The spheres are suitable for applications such as packing for liquid chromatography.

  Examples of aqueous solutions containing a precipitating agent capable of precipitating emulsion particles include alkaline earth metal halides, inorganic acids, organic acids, inorganic acid ammonium salts, organic acid ammonium salts, and alkali metal carbonates. At least one aqueous solution selected from the group consisting of, and specific examples thereof include aqueous solutions of ammonium bicarbonate, ammonium sulfate, potassium chloride, potassium bicarbonate, etc., but are not limited thereto. The aqueous solution is preferably used at a concentration of 0.05 mol / L to saturation, and more preferably 0.1 to 2.0 mol / L.

  Examples of the method for promoting the polymerization reaction include a heating method, a method of adding a polymerization accelerator, and a method of irradiating light.

  As the particle size distribution of the microspheres formed by the so-called nanoemulsion method completed as described above, the pore diameter of the micropores through which the first fluid as the dispersoid passes is uniform. Microspheres with a proper particle size are formed. Specifically, although it varies somewhat depending on the average diameter and aspect ratio of the micropores, the dispersion of the sphere diameter is preferably within 8% of the average diameter, more preferably 5% or less, and more preferably within 3%. It is preferable that

Moreover, although the microsphere obtained by the present invention has a large number of pores, the following means may be taken in order to easily control the pore diameter. That is, a micropore of a fine structure having a through-hole having a substantially uniform pore diameter and a hydrophobic surface penetrating a particle raw material-containing aqueous solution (for example, silica sol) to which a water-soluble organic polymer compound is added. Into the organic solvent. The obtained sol emulsion particles are gelated by promoting the polymerization reaction (see the above method) to form gel particles, and the gel particles are washed with water, dried and fired to obtain microspheres. In this way, the pore diameter of the microspheres can be easily controlled, and inorganic uniform microspheres composed of porous SiO ₂ spherical fine particles having substantially uniform pore diameters can be obtained.

  The water-soluble organic polymer compound is not particularly limited, and examples thereof include polyethylene glycol, sodium polystyrene sulfonate, polyacrylic acid, polyacrylamine, polyethyleneimine, polyethylene oxide, and polyvinylpyrrolidone. The amount of the water-soluble organic polymer compound used is not particularly limited, and is preferably 10 to 500% by mass based on the weight of the particle raw material before polymerization.

  The inorganic uniform microspheres produced according to the present invention include the above-mentioned liquid chromatography filler, tracer particles used for fluid measurement performed by a laser Doppler velocimeter, gas chromatography filler, liquid crystal spacer Can be used as

  In addition, as a releasable inorganic microcapsule wall material, it includes fragrances, dyes, bactericides, insecticides, insect repellents, vitamins, foods, nutrients, pharmaceuticals, deodorants, adhesives, liquid crystals, etc. Can be widely used in many fields.

  As an extender, it can also be used in the fields of anti-adhesion agents such as cosmetics, paints, plastics, inks, and films.

  Since it is possible to include colored substances such as pigments and dyes to form uniform colored microspheres, it has an excellent effect as an additive for cosmetics, inks, and plastics. Excellent performance as a magnetic tape and catalyst is also expected.

  The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.

[Example 1]
1. Electropolishing treatment A high-purity aluminum substrate (manufactured by Sumitomo Light Metal Co., Ltd., purity 99.99 mass%, thickness 0.4 mm) was cut so that it could be anodized in an area of 10 cm square, and an electropolishing liquid having the composition shown below was prepared. The electrolytic polishing treatment was performed under the conditions of a voltage of 25 V, a liquid temperature of 65 ° C., and a liquid flow rate of 3.0 m / min. The cathode was a carbon electrode, and GP0110-30R (manufactured by Takasago Seisakusho) was used as the power source. The flow rate of the electrolyte was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE).

<Electrolytic polishing liquid composition>
-660 mL of 85% phosphoric acid (reagent manufactured by Wako Pure Chemical Industries, Ltd.)
・ Pure water 160mL
・ Sulfuric acid 150mL
・ Ethylene glycol 30mL

2. Micropore formation treatment by anodic oxidation The sample obtained above after polishing is treated with an electrolyte of 0.30 mol / L sulfuric acid for 1 hour under conditions of a voltage of 25 V, a liquid temperature of 15 ° C., and a liquid flow rate of 3.0 m / min. Anodized. Furthermore, the obtained sample was immersed for 20 minutes under a condition of 40 ° C. using a mixed aqueous solution of 0.5 mol / L phosphoric acid to remove the film.
After this treatment was repeated four times, re-anodization treatment was performed for 5 hours with an electrolyte solution of 0.30 mol / L sulfuric acid at a voltage of 25 V, a liquid temperature of 15 ° C., and a liquid flow rate of 3.0 m / min. An anode in which micropores 16a are arranged in the form of a straight tube and a honeycomb on the surface of an aluminum substrate 12a shown in FIG. 1 by dipping for 20 minutes under a condition of 40 ° C. using a mixed aqueous solution of L phosphoric acid. An oxide film 14a was formed.
In both the anodizing treatment and the re-anodizing treatment, a stainless steel electrode was used as the cathode, and GP0110-30R (manufactured by Takasago Seisakusho) was used as the power source. Further, NeoCool BD36 (manufactured by Yamato Kagaku Co.) was used as the cooling device, and Pear Stirrer PS-100 (manufactured by EYELA) was used as the stirring and heating device. The flow rate of the electrolyte was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE).

3. Aluminum removal treatment The sample obtained above was immersed in a 2 mol / L mercury chloride aqueous solution at 20 ° C. for 3 hours to dissolve and remove the aluminum substrate 12b, and anodized with the micropores 16d shown in FIG. A fine structure made of the film 14d was prepared.

4). Micropore penetration treatment The sample obtained above was immersed in 30% at 30 ° C. using 5% by mass phosphoric acid to penetrate the micropore, and the anode having the micropore penetration hole 16 shown in FIG. A fine structure made of the oxide film 14 was prepared.

5). Heat treatment The fine structure shown in FIG. 3 obtained above was subjected to heat treatment for 1 hour under the condition of a load of 2.0 g / cm ^{2 and a} temperature of 400 ° C. to obtain a fine structure having the micropore of Example 1. It was.

6). Preparation of Emulsion The fine structure having micropores obtained above was used as an emulsifying film and mounted in an emulsifying apparatus as shown in FIG. 4, and a 4% aqueous solution of sodium silicate was added to polyoxyethylene (20) sorbitan trioleate 20 g / It was press-fitted into a hexane solution of L using a syringe pump. The conditions at the time of press-fitting were 1 g / cm ² per minute and a temperature of 25 ° C. This formed a large number of emulsion particles in the solution.

  Here, the apparatus shown in FIG. 4 will be briefly described. Reference numeral 30 denotes a metered syringe pump unit. A fine structure 32 having a micropore through hole is attached to the tip of the metered syringe pump unit 30. Reference numeral 34 denotes a support net for supporting the microstructure 32 having the micropore through hole. Reference numeral 36 denotes a cylindrical reaction container that is connected to the metering syringe pump unit 30. Reference numeral 20 denotes an inlet tube, which can supply the organic solvent 25 in the organic solvent beaker 24 into the reaction vessel 36 by the metering pump 22. However, the aqueous solution 31 containing the particle raw material can be quantitatively injected into the organic solvent 25 in the reaction vessel 36 by the quantitative syringe pump unit 30. The organic solvent in the reaction vessel 36 in which a large number of emulsion particles are formed is returned again to the organic solvent beaker 24 by the delivery pipe 26. The thickness of the microstructure used was 70 μm.

  When a solution in which a large number of emulsion particles were formed was added to 1 L of a 1.5 mol / L ammonium bicarbonate solution that had been dissolved beforehand, a water-insoluble precipitate gradually formed. Thereafter, the mixture was left for 2 hours, separated by filtration, washed with water, washed with methanol, and dried at 110 ° C. for 24 hours. Thus, silica microspheres (nanoemulsion) were obtained.

  The obtained silica microspheres (nanoemulsion) had an average particle diameter of 99% on a volume basis in the range of 70 to 72 nm, and the average particle diameter was 71 nm. The diameter dispersion was 2.6%.

[Example 2]
2. The silica microspheres (nanoemulsion) of Example 2 were obtained in the same manner as in Example 1 except that in the micropore formation process by anodization, the electrolytic solution was 0.50 mol / L and the voltage was 40V.

  The obtained silica microspheres (nanoemulsion) had an average particle diameter of 99% on a volume basis within a range of 111 to 107 nm, and the average particle diameter was 109 nm. The diameter dispersion was 2.9%.

[Comparative Example 1]
2. Among the micropore formation treatment by anodization, an anodization treatment was performed for 1 hour with an electrolyte solution of 0.30 mol / L sulfuric acid at a voltage of 25 V, a liquid temperature of 15 ° C., and a liquid flow rate of 3.0 m / min. Comparative Example 1 was carried out in the same manner as in Example 1 except that the mixture was immersed in a 0.5 mol / L phosphoric acid aqueous solution at 40 ° C. for 20 minutes and the four times of film removal treatment were omitted. Silica microspheres (nanoemulsion) were obtained.

  The obtained silica microspheres (nanoemulsion) had an average particle size in the range of 82 to 48 nm, 99% by volume, and an average particle size of 65 nm. The diameter dispersion was 12.3%.

Moreover, the surface photograph (magnification 20000 times) of the sample of Examples 1, 2, and the comparative example 1 was image | photographed with FE-SEM, and about average micropores and diameter of 300 arbitrary micropores in a 1 micrometer x 1 micrometer visual field. The dispersion was determined by the following formula, and the dispersion / average diameter was determined. The results are shown in Table 1.
Average diameter: μ _x = (1 / n) ΣXi
Dispersion: σ ² = (1 / n) (ΣXi ² ) −μ _x ²
Dispersion / average diameter = σ / μ _x
Here, Xi is the pore diameter of one micropore measured in the range of 1 μm ² .

For the samples of Examples 1 and 2 and Comparative Example 1, 300 micropores were used in the 1 μm × 1 μm field of view of the surface photograph (magnification 20000 times) by FE-SEM, and the following formula (1) The degree of ordering defined by is obtained. The results are shown in Table 1.
Ordering degree (%) = B / A × 100 (1)
In the above formula (1), A represents the total number of micropores in the measurement range. B is centered on the center of gravity of one micropore, and when a circle with the shortest radius inscribed in the edge of another micropore is drawn, the center of gravity of the micropores other than the one micropore is inside the circle. This represents the number in the measurement range of the one micropore to be included.

  Moreover, about the sample of Example 1, 2, and the comparative example 1, with a 1 micrometer x 1 micrometer visual field of a 100 micrometer x 100 micrometer field of view of a fractured surface photograph (magnification 1000 times) by FE-SEM, and a magnification of 20000 times, The micropores were observed and the average aspect ratio was determined. The results are shown in Table 1.

In Examples The sodium silicate fine structure used in 1 (SiO ₂ content is 5 mass%) with those directly dipped in an aqueous solution in which is dissolved to produce a nanoemulsion In this case, since the pore sealing due to hydration was suppressed, it could be used for a longer time than when an untreated microstructure was used.

[Example 3]
2. In the micropore formation process by anodic oxidation, the silica microparticles of Example 3 were obtained by the same method as Example 1 except that the electrolyte was 0.45 mol / L oxalic acid and 0.03 mol / L phosphoric acid and the voltage was 55 V. A sphere (nanoemulsion) was obtained.

  The obtained silica microspheres (nanoemulsion) had an average particle size of 99% on a volume basis within a range of 135 to 138 nm, and the average particle size was 137 nm. The diameter dispersion was 2.5%.

[Example 4]
2. In the micropore formation process by anodic oxidation, silica microspheres (nanoemulsion) of Example 4 were obtained by the same method as Example 1 except that the electrolytic solution was 0.25 mol / L sulfuric acid and the voltage was 16V.

  The obtained silica microspheres (nanoemulsion) had an average particle size of 99% on a volume basis within the range of 42 to 44 nm, and the average particle size was 43 nm. The diameter dispersion was 2.9%.

FIG. 1 is a partial cross-sectional view showing a state after anodizing treatment, (A) after anodizing treatment, (B) after film removal treatment, (C) after reanodization treatment, and (D) film removal treatment. Shown later. FIG. 2 is a partial cross-sectional view showing a state after the aluminum removal treatment. FIG. 3 is a partial cross-sectional view showing the through hole of the micropore. FIG. 4 is a schematic view showing an emulsion production apparatus.

Explanation of symbols

1, 2, 4, 5, 7, 8 Micropores 3, 6, 9 Circles 12a, 12b: Aluminum substrates 14, 14a, 14b, 14c, 14d: Anodized films 16a, 16b, 16c, 16d: Micropores 16: Micropore through-hole 20: Inlet tube 22: Metering pump 24: Organic solvent beaker 25: Organic solvent 30: Metering syringe pump unit 31: Aqueous solution containing particle raw material 32: Micro structure 34:32 having micropore through-hole Support network 36 for supporting the reaction vessel

Claims (4)

Through a microstructure having micropore through-holes in which the dispersion of micropore diameter obtained by anodizing aluminum or aluminum alloy is within 3% of the average diameter,
Place the liquid that becomes the dispersoid on one side, the liquid that becomes the dispersion medium on the other side,
A method for producing a nanoemulsion, wherein the liquid as the dispersoid passes through the micropores and is dispersed in the liquid as a dispersion medium.   The method according to claim 1, wherein the liquid as the dispersoid is pressurized and passed through the micropores.   The method for producing a nanoemulsion according to claim 1 or 2, wherein the aspect ratio of the micropore is an average value of 10 or more and less than 10,000. The manufacturing method of the nanoemulsion in any one of Claims 1-3 whose degree of ordering defined by following formula (1) is 50% or more about the said micropore.
Ordering degree (%) = B / A × 100 (1)
In the above formula (1), A represents the total number of micropores in the measurement range. B is centered on the center of gravity of one micropore, and when a circle with the shortest radius inscribed in the edge of another micropore is drawn, the center of gravity of the micropores other than the one micropore is inside the circle. This represents the number in the measurement range of the one micropore to be included.

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