JP2016144777A - Foam inhibiting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam inhibiting method capable of suppressing occurrence of foam by irradiation of an object for which the foam is to be suppressed with microwaves.SOLUTION: A foam inhibiting method comprises: irradiating an object O with microwaves MW to suppress occurrence of foam on the object O.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a foam suppression method that suppresses the generation of bubbles.

In various technical fields that handle liquids, there are concerns about adverse effects such as a decrease in production efficiency, a decrease in yield, and a decrease in quality due to the generation of bubbles in the liquid. For example, when applying the prepared coating solution to a substrate or the like, if a coating solution in which bubbles are generated by a stirring operation or the like performed before that is applied as it is, defects on the coating film surface or uneven coating may occur. There is a risk of causing this.
In order to avoid such an adverse effect, for example, Patent Document 1 proposes a defoaming method in which a plurality of ultrasonic waves having different frequency bands are simultaneously irradiated onto the coating liquid to defoam the coating liquid.

JP-A-2005-161164

  However, the defoaming method of Patent Document 1 is to promote vibration of the interface between the liquid and the bubbles in the liquid by irradiating ultrasonic waves to dissolve the bubbles in the liquid, and the liquid is difficult to foam. It was not to do. In other words, the defoaming method of Patent Document 1 is for eliminating the foam once generated, and the idea of suppressing the generation of foam was lacking.

  In the research conducted by the present inventor, it is found that dissolved oxygen in a liquid is easily degassed when irradiated with microwaves, and the dissolved oxygen can be degassed at a higher degassing rate than the solubility decreases due to temperature rise. Have gained. Therefore, after intensive studies based on such knowledge, by irradiating the liquid with microwaves, the dissolved gas which causes bubbles such as dissolved oxygen is efficiently degassed, The inventors have found that generation can be suppressed, and have completed the present invention.

  That is, an object of the present invention is to provide a foam suppression method capable of suppressing the generation of bubbles by irradiating the object to be suppressed with microwaves.

  The bubble suppression method according to the present invention is a method for suppressing the generation of bubbles in the object by irradiating the object with microwaves.

  According to the present invention, generation of bubbles can be suppressed by irradiating the object to be suppressed with microwaves.

Schematic which shows an example of the apparatus which can implement suitably the foam suppression method which concerns on embodiment of this invention. It is explanatory drawing which shows the height of the bubble which generate | occur | produced in the sample liquid level measured in an Example and a comparative example.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of an apparatus that performs the foam suppression method according to the present embodiment. The foam suppression apparatus 1 includes a processing chamber 2, a placement unit 3, a microwave oscillator 4, and a power feeding unit. And 5.

The processing chamber 2 can be formed in a box shape so as to form a closed space and prevent leakage of the microwave MW. The placement unit 3 is a part on which the container 6 into which the object O to be suppressed is put is placed.
In FIG. 1, the rectangular parallelepiped pedestal member placed on the inner bottom surface of the processing chamber 2 is used as the mounting portion 3, but the inner bottom surface itself of the processing chamber 2 may be used as the mounting portion 3.

The microwave oscillator 4 is a device that generates and outputs a microwave MW. A magnetron or a semiconductor oscillator can be used, but a semiconductor oscillator that can easily control the oscillation frequency and output is preferably used.
The semiconductor oscillator includes a microwave generation unit configured using a semiconductor element. The microwave generation unit is configured by, for example, a semiconductor amplification element such as a transistor and a resonance circuit such as a tank circuit. For the microwave generator, a Hartley oscillation circuit, a Colpitts oscillation circuit, or the like can be used. In addition to the microwave generator, the semiconductor oscillator can have a function of changing the frequency of the microwave MW, a function of changing the output of the microwave MW, and the like.

  The power feeding unit 5 is provided at one place or two or more places in the wall portion, top surface portion, and bottom surface portion inside the processing chamber 2, and radiates the microwave MW output from the microwave oscillator 4 into the processing chamber 2. To do. For example, an array antenna, a planar array antenna, a phased array antenna (phase scanning antenna), or the like can be used for the power supply unit 5. As the radiating element of the array antenna, for example, a microstrip antenna (patch antenna), a slot antenna, a dipole antenna, or the like can be used.

In the present embodiment, using such a foam suppression device 1, for example, water or various aqueous solutions using water as a solvent is put into the container 6 as the object O and irradiated with the microwave MW.
The microwave MW generally refers to an electromagnetic wave having a wavelength of 1 m to 100 μm and a frequency of 300 MHz to 3 THz. In the present embodiment, the microwave MW irradiated to the object O is a microwave having a frequency that is legally used. Waves can be used.

  According to such a foam suppression method according to the present embodiment, it is possible to suppress generation of bubbles in the object O by irradiating the object O with the microwave MW.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

[Examples 1 to 8]
Samples are prepared by adding 10 drops of commercially available household liquid detergent to 1 L of ion-exchanged water, and 40 mL of the sample is poured into each of the nine prepared glass containers as an object to be defoamed. I put it. One of these was set as an untreated relative proportion, and the remainder was set as Examples 1 to 8 and irradiated with microwaves under the following conditions.

<Examples 1-4>
Example 1: Microwave (frequency 2.45 GHz) was irradiated until the temperature of the sample reached 60 ° C. (irradiation time 60 seconds)
Example 2: Microwave (frequency: 2.45 GHz) was irradiated until the temperature of the sample reached 80 ° C. (irradiation time: 105 seconds)
Example 3: Irradiation with microwaves (frequency 2.45 GHz) until the sample temperature reached 90 ° C. (irradiation time 140 seconds)
Example 4: Microwave (frequency: 2.45 GHz) was irradiated until the temperature of the sample reached 90 ° C., and then the output was lowered to maintain the temperature of 90 ° C. and microwave irradiation was continued for 180 seconds.

<Examples 5 to 8>
Example 5: Microwave (frequency 5.8 GHz) was irradiated until the temperature of the sample reached 60 ° C. (irradiation time 45 seconds)
Example 6: Microwave (frequency 5.8 GHz) was irradiated until the temperature of the sample reached 80 ° C. (irradiation time 95 seconds)
Example 7: Microwave (frequency 5.8 GHz) was irradiated until the temperature of the sample reached 90 ° C. (irradiation time 120 seconds)
Example 8: Microwave (frequency 5.8 GHz) was irradiated until the temperature of the sample reached 90 ° C, and then the output was lowered so as to maintain the temperature of 90 ° C, and microwave irradiation was continued for 180 seconds.

  In any of Examples 1 to 8, foaming was observed on the liquid surface of the sample heated by microwave irradiation, but the sample was allowed to stand until the bubbles disappeared from the liquid surface of the sample and allowed to cool naturally.

[Evaluation]
In contrast, for each of Examples 1 to 8, the glass container was capped, and the bubbling of the sample liquid surface immediately after shaking 10 times up and down under the same conditions was observed. No microwave was irradiated. There was little foaming of Examples 1-8 compared with contrast. Table 1 shows the rate of reduction of the height of the foam relative to the proportionality, together with the measured value of the height H (see FIG. 4) of the foam generated on the sample liquid surface.

[Comparative Examples 1-4]
Four glass containers similar to those of the example were prepared, and 40 mL of the sample prepared in the example was poured into each container and allowed to stand. These were designated as Comparative Examples 1 to 4, and a heating wire was wound around the outer peripheral surface of each glass container and energized under the following conditions.

Comparative Example 1: Energization was performed until the temperature of the sample reached 60 ° C. (energization time 58 seconds)
Comparative Example 2: Energization was performed until the temperature of the sample reached 80 ° C. (energization time 100 seconds)
Comparative Example 3: Energization was performed until the temperature of the sample reached 90 ° C. (energization time 130 seconds)
Comparative Example 4: Energization was performed until the temperature of the sample reached 90 ° C., and then the output was lowered so as to maintain the temperature of 90 ° C. and the energization was continued for 180 seconds.

  In any of Comparative Examples 1 to 4, although bubbling was observed on the liquid surface of the heated sample, the sample was left to stand until the bubbles disappeared from the liquid surface of the sample and allowed to cool naturally. Thereafter, the glass container was covered, and the height H of bubbles generated on the sample liquid surface immediately after shaking up and down 10 times under the same conditions as in the example was measured. Along with the value, the decreasing rate of the bubble height with respect to the proportionality is shown in Table 1.

From these results, it can be seen that the generation of bubbles can be suppressed by irradiating the microwave, the higher the frequency of the microwave, and the higher the heating temperature of the sample, the higher the suppression effect, The effect of suppressing the generation of bubbles can be confirmed more clearly by visually observing the state of foam formation on the sample liquid surface rather than comparing numerically.
Moreover, although the effect which suppresses generation | occurrence | production of a bubble can be confirmed even if it heats by the radiant heat from a heating wire, the effect is remarkably inferior compared with microwave irradiation. This is because part of the dissolved gas is degassed from the sample due to a decrease in the solubility of the dissolved gas due to heating, but the microwave irradiation dissolves more than the decrease in the solubility of the dissolved gas due to the temperature rise of the sample. This is probably because the gas could be degassed from the sample.

  Moreover, when the sample was microwave-heated under the same conditions as in Examples 1 to 8, the sample was allowed to stand for 10 days and evaluated in the same manner. It was confirmed that the effect was sustained. On the other hand, in the case where the sample was heated under the same conditions as in Comparative Examples 1 to 4, as the standing time after heating the sample became longer, the rate of decrease in the height of the bubble relative to the proportionality became smaller, The antifoam effect was gradually lost.

  While the present invention has been described with reference to the preferred embodiment, it is needless to say that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

  For example, in the above-described embodiment, the object O is put into the container 6 and irradiated with the microwave MW, but the microwave MW may be irradiated while continuously circulating the object O through a predetermined pipe. Good.

  INDUSTRIAL APPLICABILITY The present invention can be used in various fields in which the generation of bubbles is suppressed and the harmful effects due to the generation of bubbles are a concern.

O Object MW Microwave

Claims (2)

  A method of suppressing bubbles, wherein the object is irradiated with microwaves to suppress generation of bubbles in the object.   The bubble suppression method of Claim 1 which produces | generates a microwave using a semiconductor type oscillator.

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