JP3218445B2 - Ultrasonic emulsification method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications] Unused fields include food, medicine, cosmetics, industrial chemicals, and the like, including the use of conventional ultrasonic emulsifiers for dispersion of paints, photosensitive emulsions, waxes, rolling oils, etc.
And use for high-purity chemical products.

[0002]

FIG. 5 is a schematic view of a conventional ultrasonic emulsification method.
The liquid A and the liquid B, which have been pre-stirred, enter the emulsification chamber (14) through the entrance (18) as shown by the arrow, and
When passing through the narrow emulsification gap (16) between the horn (13) and the end surface (17) of the horn (13), the horn is emulsified by contacting the ultrasonically vibrated horn end surface (17), and the outlet ( 11) It flows out as indicated by the arrow. To produce a high-quality emulsion by the conventional ultrasonic emulsification method shown here,
It is necessary to apply ultrasonic vibration of several tens μm level of double amplitude to the horn end face (17) in contact with the liquid interface of both A and B, and the ultrasonic generator generates power of several tens W / cm ^{2 at} the horn. The horn must be driven with (power). Therefore, the ultrasonic frequency is limited to a relatively low region around 20 KHZ. The reason for this is to adopt a low frequency so that relatively large ultrasonic power can be handled, and to further increase the emulsification flow rate to a level suitable for industrial purposes. However, despite this effort, ultrasonic emulsification methods have tended to be costly per unit flow in many cases, limiting their use. In addition, the above-described ultrasonic vibration having a large amplitude of several tens of μm level causes erosion due to cavitation erosion of the horn vibration surface to proceed more quickly, and the frequency of replacement of expensive horns increases. The quality of the emulsified liquid is deteriorated and the maintenance cost is increased, for example, when metal ions are mixed. Further, when the preliminary stirring before entering the ultrasonic emulsifying apparatus is insufficient, coarse particles are often mixed, and there is a problem in process control. The reason for this is that unless all the dispersed particle diameters are reduced to below the critical particle diameter determined by the characteristics of the process by preliminary stirring, the dispersing action of the ultrasonic wave within the time when the liquid passes through the gap for emulsification (16) is required. This is because it becomes insufficient.

[0003]

The first problem is to reduce the power required for producing an emulsion. Since power is directly related to initial investment and operating cost, it is desired to make an emulsion with as little power as possible in order to spread the ultrasonic emulsification method. For this purpose, it is necessary to devise whether emulsification can be performed with an amplitude smaller than that conventionally required. The second problem is to ensure the uniformity of the particle diameter of the emulsion dispersion, that is, to reduce the chance of forming coarse particles. Conventionally, countermeasures have been taken by strengthening the preliminary stirring or reducing the amount of processing per hour, but both have been economically disadvantageous. A third object is to prevent metal fine powder from being mixed into the emulsion due to erosion of the horn and to prevent metal ions from being dissolved from the horn metal material. This is necessary for handling food, pharmaceuticals and high-purity chemical products.

[0004]

In order to finely disperse the liquid B as a dispersoid in the liquid A to form a B / A type emulsion, as a means for solving the problem, a small contact with the liquid B is considered. After forming a wet thin film of the liquid B on the surface of the solid having the corners, the liquid B is immersed in the liquid A to which an ultrasonic wave is applied to generate an emulsion.

[0005]

As a result of repeated experiments to solve the first problem, the present inventors have found the following facts. That is, liquid B
The liquid B is applied to a solid material having a small contact angle with respect to the liquid B so that the liquid B is spread thinly and then immersed in the liquid A to which ultrasonic vibration of a cleaning machine level is applied without using a horn. Is finely divided into particles having a particle size equal to or less than the particle size obtained by a conventional horn, and dispersed in the liquid A. At this time, the dispersed liquid B is entrapped in the continuous phase of the liquid A having poor wettability to the solid material,
Does not reattach to solid materials. Therefore, the solid material separated from the liquid B is pulled up from the liquid A, the liquid B is applied again so that the liquid B spreads thinly, and is repeatedly immersed in the liquid A to which the ultrasonic vibration is applied. can get.
The effect of the present invention is to reduce the amplitude level required for emulsification to about 1/10 or less by previously forming a thin film of a liquid to be a dispersoid on a solid surface. For this reason, a reduction in power and an increase in the area for producing an emulsion, that is, an increase in the amount of treatment are realized. Further, since all the dispersoids are uniformly thinned, not only the preliminary stirring is unnecessary but also the particle diameter is made uniform. Therefore, the above-mentioned second problem is also solved. Further, in the present invention, since the amplitude is reduced to about one-tenth or less, the chance of occurrence of erosion erosion is greatly reduced and can be practically ignored. Therefore, the third problem described above disappears.

[0006]

1 to 4 show an example of an emulsifying method and apparatus according to the present invention. FIG. 1 is an explanatory view showing the method of the present invention. The ultrasonic vibrator (6) is driven by an ultrasonic oscillator (not shown) and applies ultrasonic vibration to the liquid A (2) contained in the container (1). The thin film (4-1) of the liquid B is formed on the solid material (3) by applying the liquid B (4) thinly. By dipping the solid material (3) having good wettability in the liquid A, the thin film (4-1) of the liquid B is dispersed as fine particles in the liquid A (2), and a B / A type emulsion is prepared. (5) is generated. The ultrasonic frequency used here is determined by the existing method.
The optimum one for emulsification can be selected from a low range of about 20 KHZ to a range exceeding 1 MHZ. The following is an example.

[0007] Ultrasonic frequency 26KH made for cleaning purposes
As a result of performing the above test using a diaphragm type ultrasonic generator having a Z, an output of 600 W and a power density of 1 W / cm ² ,
The dispersion state of liquid B in water is in the range of several microns to submicron, and it has been confirmed that an emulsion that is equal to or higher than the conventional ultrasonic emulsification method including uniformity and stability can be obtained. did it.

FIG. 2 shows a solid material having good wettability with respect to the liquid B (4) as a set of rollers (3-1) rotating in close contact with each other as a thinning means. An example of an apparatus for spreading the supplied liquid B (4) into a thin film by contact rotation of the roller to obtain an emulsion having a desired concentration will be described. Provide a supply port (10) for the liquid A (2) and an outlet (11) for the emulsion, and continuously supply the liquid A (2) and the liquid B (4) to continuously obtain a constant concentration of the emulsion. Can be. Of course, batch processing is also possible. A set of rollers (3
It is easy to increase the diameter and the axial length of -1), and the processing amount can be easily increased economically by increasing the number of required vibrators (6).

FIG. 3 shows a container (1-1) made of resin or the like for containing the liquid A (2), and a solid material having good wettability with respect to the liquid B (4) is formed of a nonmetallic material such as ceramics or resin. 3 shows a roller (3-1) made of the same. Obviously, the liquid A (2) and the liquid B (4) both obtain an emulsion (5) without contacting the metal. (8)
Plays a role of transmitting ultrasonic vibrations into the liquid A (2) via the container (1-1), and is called ultrasonic transmission water.

FIG. 4 shows an example in which a solid material having good wettability with respect to the liquid B (4) is constituted by a belt (3-2). When the belt moves in the direction indicated by the arrow, the liquid B (4) in the container (9) adheres to the surface, is thinned by a set of squeegee rollers (12), and is subjected to ultrasonic vibration. It is dispersed in A (2) to obtain a B / A type emulsion (5). This example is a batch process in which the liquid A (2) and the emulsion (5) coexist in the container (1).

[0011]

According to the present invention, it is possible to use an inexpensive diaphragm type vibrator widely used for ultrasonic cleaning instead of an expensive horn type vibrator, and to obtain a wider ultrasonic radiation area (10 times as large as that of the conventional one).
The size of the ultrasonic emulsifier can be increased economically. The uniformity of the dispersed particles is enhanced by thinning, and an open emulsification tank can be adopted if necessary, which facilitates cleaning and maintenance. In addition, it has the effect of obtaining an emulsion without contacting metal. This has provided a technical basis for greatly expanding the use of ultrasonic emulsification to fields such as food and pharmaceuticals.

[Brief description of the drawings]

 FIG. 1 is an explanatory view of an ultrasonic emulsification method according to the present invention. FIG. 2 is an example of an ultrasonic emulsifying apparatus according to the present invention. FIG. 3 is an example of a non-metallic ultrasonic emulsifying apparatus according to the present invention. FIG. An example of an emulsifying device Fig. 5: Schematic diagram of a conventional ultrasonic emulsifying method

[Description of Signs] 1 ・ ・ ・ Container for storing liquid A 7 ・ ・ ・ Outer container 1-1 ・ Same as above (made of resin) 8 ・ ・ ・ Ultrasonic transmission water 2 ・ ・ ・ Liquid A 9 ・ ・ ・ Liquid B 3 ... Solid material to apply liquid B 10 ... Supply port for liquid A 3-1. Same as above (roller) 11 ... Emulsion liquid outlet 3-2. Same as above (belt) 12. Squeegee roller 4 Liquid B 13 Horn 4-1 Thin film of liquid B 14 Emulsification chamber 5 B / A type of liquid B and liquid A 15 Gap adjusting plate Emulsion liquid 16 ... gap for emulsification 6 ... ultrasonic vibrator 17 ... horn end face 18 ... entrance of preliminary stirring liquid

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01F 3/08 B01F 11/02 B01J 19/10

Claims (3)

(57) [Claims] When a liquid B serving as a dispersoid is finely dispersed in a liquid A to form a B / A emulsion, the liquid B is wetted on a solid surface having a small contact angle with the liquid B. An ultrasonic emulsification method comprising forming a thin film, immersing the thin film in a liquid A to which ultrasonic waves are applied, and generating an emulsion. 2. An ultrasonic generator for applying ultrasonic waves to the liquid A, a container for storing the liquid A, and a solid surface partially immersed in the liquid A and having good wettability with respect to the liquid B. An ultrasonic emulsifying apparatus comprising a liquid B thinning means. 3. A member in contact with the liquid A and the liquid B according to claim 2, wherein the member is made of a nonmetallic material, and the ultrasonic vibration
An ultrasonic emulsifying apparatus characterized in that the ultrasonic emulsifying apparatus is indirectly applied from outside of a container storing the water through ultrasonic transmission water.