WO2015129805A1

WO2015129805A1 - Material mixing method

Info

Publication number: WO2015129805A1
Application number: PCT/JP2015/055604
Authority: WO
Inventors: 明生中原; 洋介松尾; 丸人伊藤; 瞭汰米山
Original assignee: 学校法人日本大学
Priority date: 2014-02-28
Filing date: 2015-02-26
Publication date: 2015-09-03
Also published as: JPWO2015129805A1; JP6565067B2

Abstract

This material mixing method has: a step in which an external field is applied to a mixed material in which a particulate solid material and liquid material, or colloid particles and a colloid particle dispersion medium are mixed such that the volume ratio is equal to or higher than the liquid limit and equal to or lower than the plastic limit; and a step in which the mixed material is left to stand, and then an ultrasonic vibration having an energy exceeding the yield stress of the mixed material is propagated inside the mixed material.

Description

Material mixing method

The present invention relates to a material mixing method.
This application claims priority based on Japanese Patent Application No. 2014-038777 for which it applied on February 28, 2014, and uses the content here.

Conventionally, the operation of mixing two or more kinds of materials, such as a mixed material in which a solid material and a liquid material are mixed, or a mixed material in which a liquid material and a liquid material are mixed, is often used in many paints, cosmetics, and architectures. Much has been done in the field. The behavior of such a mixed material varies greatly depending on the concentration.

For example, as a result of investigations by the inventors, a solid-liquid mixed material obtained by mixing a solid material and a liquid material has a mechanical external field such as a flow and vibration during stirring when the solid material has a high concentration so as to exhibit plasticity. As a result, it was found that a micro and anisotropic close-packed structure was formed in the inside depending on the direction of the external field (see, for example, Non-Patent Document 1).

For example, when a high-concentration solid-liquid mixed material is reciprocated in one direction and vibrated, a dense structure due to compression waves generated in the vibration direction is formed inside the solid-liquid mixed material. Further, when a high-concentration solid-liquid mixed material is flowed, a dense structure due to the shear stress of the flow is formed inside the solid-liquid mixed material. That is, in the solid-liquid mixed material, a dense structure having anisotropy is formed according to a dynamic external field.

As described above, when the solid-liquid mixed material that appears uniform at first glance has an anisotropic dense structure when viewed microscopically, for example, the following problems may occur.

Regarding the above phenomenon, when mortar is assumed as the solid-liquid mixed material, the concrete body obtained from the mortar in which the anisotropic dense structure is formed may have anisotropy in strength.

Also, when a chemical reaction is allowed to proceed in a solid-liquid mixed material, it is expected that a reaction is more likely to occur in a dense part than in a relatively sparse part. That is, as a whole reaction system, a portion where a chemical reaction easily proceeds and a portion where a chemical reaction hardly proceeds are generated. In such a reaction system, the reaction may occur non-uniformly.

However, the anisotropic dense structure inside the solid-liquid mixed material has not been studied in the past. Therefore, a technique for eliminating the anisotropic dense structure of the solid-liquid mixed material has not been known.

In the above, the case where the mixed material having a dense structure is a solid-liquid mixed material has been described. However, even when, for example, a liquid material and a liquid material are mixed, in the case of a dispersion system in which one liquid material is colloidally dispersed in the other liquid material, the mixed material of the liquid material and the liquid material is When it has plasticity, the above-mentioned dense structure can be formed in the mixed material. In that case, a similar problem may occur.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a material mixing method capable of reducing the anisotropy of the dense structure included in the mixed material.

In order to solve the above problems, according to one embodiment of the present invention, a particulate solid material and a liquid material, or a colloidal particle and a dispersion medium of the colloidal particle have a volume ratio that is greater than a liquid limit and less than a plastic limit. Applying an external field to the mixed material mixed in step (b), and allowing the ultrasonic vibration having energy exceeding the yield stress of the mixed material to propagate inside the mixed material after the mixed material is allowed to stand. A material mixing method is provided.

In one aspect of the present invention, the external field may be a dynamic external field.

In one embodiment of the present invention, the particulate solid material may be a dielectric or a magnetic material, and the external field may be an electromagnetic external field.

Another embodiment of the present invention is to obtain a particulate solid material and a liquid material, or a colloidal particle and a dispersion medium of the colloidal particle while mixing so that the volume ratio is higher than the liquid limit and lower than the plastic limit. There is provided a material mixing method including a step of propagating ultrasonic vibration having energy exceeding the yield stress of the mixed material inside the mixed material.

Another embodiment of the present invention is obtained by mixing particulate solid material and liquid material, or colloidal particles and a dispersion medium of the colloidal particles so that the volume ratio is higher than the liquid limit and lower than the plastic limit. Provided is a material mixing method including a step of propagating ultrasonic vibration having energy exceeding the yield stress of the mixed material inside the mixed material in a state where the mixed material is left standing.

In one aspect of the present invention, the step of propagating the ultrasonic vibration may be a method of propagating the ultrasonic vibration from a plurality of directions with respect to the solid-liquid mixed material.

According to the present invention, it is possible to provide a material mixing method that can reduce the anisotropy of the dense structure included in the mixed material.

It is a photograph which shows the result of an Example. It is a photograph which shows the result of a comparative example. It is a schematic diagram which shows the experimental apparatus used in an Example. It is a photograph which shows the result of an Example. It is a photograph which shows the result of an Example. It is a photograph which shows the result of an Example. It is a photograph which shows the result of a comparative example. It is a graph which shows the result of an Example.

In the first material mixing method according to the present embodiment, the particulate solid material and the liquid material, or the colloidal particles and the dispersion medium of the colloidal particles are mixed so that the volume ratio is not less than the liquid limit and not more than the plastic limit. Adding an external field to the mixed material, and after allowing the mixed material to stand, propagating ultrasonic vibration having energy exceeding the yield stress of the mixed material to the inside of the mixed material.

Alternatively, in the second material mixing method according to this embodiment, the particulate solid material and the liquid material, or the colloidal particles and the dispersion medium of the colloidal particles are set so that the volume ratio is not less than the liquid limit and not more than the plastic limit. And mixing ultrasonic vibration having energy exceeding the yield stress of the mixed material into the obtained mixed material.

Alternatively, in the third material mixing method according to the present embodiment, the particulate solid material and the liquid material, or the colloidal particles and the dispersion medium of the colloidal particles are set so that the volume ratio is not less than the liquid limit and not more than the plastic limit. A step of propagating ultrasonic vibration having energy exceeding the yield stress of the mixed material in the mixed material in a state in which the mixed material obtained by mixing is left standing.

Here, the “volume ratio” in this specification specifically refers to a value represented by the following formula (1) or formula (2). The unit of volume ratio is “%”.

When the material to be mixed is a solid material and a liquid material, the volume ratio is defined by the above formula (1). When the materials to be mixed are colloidal particles and a dispersion medium, the volume ratio is defined by the above formula (2).

In this specification, “yield stress of mixed material” refers to a value obtained by using a rheometer (Physica MCR301, manufactured by Anton Paar) after adjusting the mixed material.

A specific method for measuring the yield stress is as follows.
The mixed material is sandwiched between two parallel plates placed horizontally, and the upper parallel plate is rotated in one direction by applying torque to the upper parallel plate with the lower parallel plate fixed. Thereby, a shear stress is applied to the mixed material sandwiched between the two parallel plates. By measuring the shear rate representing the fluidity of the mixed material as a function of the strength of the shear stress, the shear stress at which the mixed material begins to flow is obtained. This “shear stress when the mixed material starts to flow” is defined as a yield stress to be obtained.

In the present specification, the “liquid limit” refers to the volume ratio of the boundary between the liquid state and the plastic state in a liquid mixed material obtained by mixing a solid material and a liquid material or colloidal particles and a dispersion medium. . Specifically, when the yield stress of the solid-liquid mixed material is measured by the above-described method, the volume ratio is such that the yield stress value is 0 Pa.

In addition, in this specification, the “plastic limit” refers to the volume ratio of the boundary between the plastic state and the semi-solid state for a mixed material obtained by mixing a solid material and a liquid material or a colloidal particle and a dispersion medium. Specifically, when the yield stress of the mixed material is measured by the above-described method, the volume ratio indicates the volume ratio at which the yield stress exceeds the measurement limit.

That is, when the volume ratio of the mixed material is not less than the liquid limit and not more than the plastic limit, the mixed material is a plastic body.

The “liquid limit” and “plastic limit” of the mixed material are values that vary depending on the combination of the solid material and the liquid material used, or the combination of the colloidal particles and the dispersion medium. Therefore, before carrying out the material mixing method of the present invention, it is advisable to conduct preliminary experiments and obtain respective values.

Further, the “yield stress” of the mixed material is a value that varies depending on the volume ratio of the mixed material. Therefore, before carrying out the material mixing method of the present invention, a preliminary experiment is performed to determine the yield stress for each of a plurality of volume ratios, and a correspondence table or graph showing the relationship between the volume ratio of the mixed material and the yield stress is created. It is good to keep.
Hereinafter, the material mixing method of this embodiment is demonstrated in order.

(Solid material)
In the material mixing method of the present embodiment, any of inorganic materials and organic materials can be used as long as the solid material is particulate and can be mixed with a liquid material to form a plastic body. Here, “particulate” includes both powdery and granular. The particle size distribution of the solid material may be monodispersed or polydispersed.

The solid material may be insoluble or soluble in the liquid material described later. In the case where the solid material is soluble in the liquid material, the present embodiment is applied to the mixed material in which the solid material is dispersed in the liquid material by mixing the solid material at a saturation concentration or higher of the liquid material. The liquid mixing method can be applied.

The organic material may be food powder such as starch (corn starch, starch starch, potato starch), wheat flour, rice flour, or various organic compound powders.

Inorganic materials include calcium carbonate, calcium fluoride, basic magnesium carbonate (also known as magnesium carbonate hydroxide (mMgCO ₃ · Mg (OH) ₂ · nH ₂ O, typical values are m = 4, n = 5)) ) And other salts;
Minerals such as clay and mud represented by kaolin and bentonite;
Carbon materials such as coal, activated carbon, graphene and carbon nanotubes;
Metal oxides;

The metal oxide may be an oxide containing one kind of metal such as magnesium oxide, magnetic iron oxide, titanium oxide, and barium titanate. LiCoO ₂ , Li ₂ FeO ₄ , ITO (indium-tin- An oxide containing two or more kinds of metals may be used.

(Liquid material)
Further, the liquid material used in the material mixing method of the present embodiment may be either water or an organic solvent. As the organic solvent, various commonly known solvents such as alcohols such as methanol and ethanol, hydrocarbons such as hexane, decane and petroleum ether, as well as ethers, ketones, amines and esters can be used.

Note that a substance soluble in the liquid material may be dissolved in the liquid material. The “soluble substance” may be an organic substance or an inorganic substance.

These solid materials and liquid materials may be used alone or in combination of two or more.

(Material mixing method)
Next, the material mixing method will be described.
In the first material mixing method, first, the above-mentioned solid material and liquid material, or colloidal particles and dispersion medium are mixed so that the volume ratio is not less than the liquid limit and not more than the plastic limit. Thereby, the mixed material of a plastic body is obtained.

However, if the mixed material is a plastic body (the volume ratio is greater than the liquid limit and less than the plastic limit), when the mixed material is subjected to an external field, the mixed material will be subjected to the direction of the external field. Thus, a micro dense / dense structure having anisotropy is formed.

The “external field” as used in this specification includes both “dynamic external field” and “electromagnetic external field”.
“Mechanical external field” refers to a shearing force applied to the mixed material when the mixed material is agitated or fluidized, or a vibration applied to the mixed material by reciprocating the mixed material in one direction.
“Electromagnetic external field” includes “electrical external field” and “magnetic external field”. “Electromagnetic external field” refers to an electric or magnetic external force applied to a mixed material when the solid particles constituting the mixed material are a dielectric or magnetic material. For example, Coulomb force or Lorentz force Is mentioned. The electromagnetic external field may be stationary or time-varying. Examples of stationary external electromagnetic fields include those caused by direct current. Moreover, what originated in alternating current is mentioned as what an electromagnetic external field fluctuates with time.

For example, when the mixed material is stirred, a dense structure is formed in a direction crossing the flow direction of stirring. Further, when the mixed material is flowed, a dense structure is formed in a direction crossing the flow direction. Specifically, the “sparse” portion extending along the flow direction and flow direction of stirring and the “dense” portion extending along the flow direction and flow direction of stirring are divided into the flow direction and flow of stirring. A plurality are alternately formed in a direction crossing the direction.

In addition, when an electric field or a magnetic field is applied to a mixed material using a dielectric or magnetic substance as a dispersoid, a dense structure is formed in a direction intersecting the electric field direction or the magnetic field direction. Specifically, the “sparse” part that extends along the electric field direction and the magnetic field direction and the “dense” part that extends along the electric field direction and the magnetic field direction intersect with the electric field direction and the magnetic field direction. A plurality are alternately formed.

Also, when the solid-liquid mixed material is shaken, a dense structure is formed in the direction of vibration. Specifically, a plurality of sparse portions extending in a direction intersecting the excitation direction and dense portions extending in a direction intersecting the excitation direction are alternately formed in the excitation direction.

Therefore, in the first material mixing method of the present embodiment, after leaving the mixed material, the ultrasonic vibration having energy exceeding the yield stress of the mixed material is propagated inside the mixed material (the ultrasonic vibration is propagated). Process). As a result, inside the mixed material, the solid material or colloidal particles are shaken, the micro-dense dense structure is reduced, and a mixed material having a uniform structure can be obtained.

For example, when the mixed material obtained by using the first material mixing method is solidified or cured, a molded body having a uniform structure having no sparse / dense structure can be obtained.

In the second material mixing method, the above-mentioned solid material and liquid material are mixed so that the volume ratio is not less than the liquid limit and not more than the plastic limit. Propagate ultrasonic vibrations with energy exceeding the yield stress.

During the mixing of the above-mentioned volume ratio of the mixed material, an anisotropic dense structure is formed inside the mixed material due to the external field applied by mixing at a certain moment. The resulting new sparse / dense structure is formed. That is, a dense structure is always formed inside the mixed material.

Therefore, in the second material mixing method of this embodiment, ultrasonic vibration is propagated inside the mixed material while mixing. As a result, the solid material or colloidal particles are shaken during mixing of the mixed material, the formation of a micro and anisotropic dense structure is suppressed, and a mixed material having a uniform structure can be obtained.

For example, when a chemical reaction is caused in a mixed material while mixing a solid material and a liquid material, or a colloidal particle and a dispersion medium using the second material mixing method, the concentration difference is reduced in a micro reaction field. Therefore, a chemical reaction can be caused under more uniform concentration conditions.

Also, in the third material mixing method of the present embodiment, ultrasonic vibration is propagated inside the mixed material while the mixed material obtained by mixing is left standing. As a result, the solid material or colloidal particles are shaken during mixing of the mixed material, the formation of a micro and anisotropic dense structure is suppressed, and a mixed material having a uniform structure can be obtained.

The propagation of ultrasonic vibration is usually performed using an ultrasonic vibrator. The propagation of the ultrasonic vibration may be performed from a plurality of directions with respect to the mixed material. This ultrasonic irradiation from a plurality of directions may be realized, for example, by using a single ultrasonic transducer and performing ultrasonic irradiation from a plurality of directions. You may implement | achieve by performing irradiation.

∙ Ultrasonic vibration propagating inside the mixed material gradually loses energy inside the mixed material and attenuates until it eventually falls below the yield stress of the mixed material. Therefore, for example, in the first material mixing method and the third material mixing method, it is assumed that it is difficult to propagate ultrasonic vibrations to the entire mixed material by ultrasonic irradiation in one direction from one place. Is done. For example, the amount of the mixed material to be left is large, or the container in which the mixed material to be left is stored is long. Even in such a case, ultrasonic irradiation can be performed on a desired region by performing ultrasonic irradiation from a plurality of directions.

In addition, when propagating ultrasonic vibration from a plurality of directions to the mixed material, the ultrasonic vibration may be propagated throughout the mixed material. It is also possible not to perform sound wave irradiation.

For example, if mortar is assumed as the mixed material, ultrasonic treatment is applied to some areas and no ultrasonic irradiation is applied to the remaining areas, so that some areas have a uniform internal structure. In the remaining area, a mixed material having a dense structure is obtained. A concrete molded body obtained from such a mortar is expected to have a relatively low strength in a portion corresponding to a mortar having a dense structure compared to a portion corresponding to a mortar having a uniform internal structure. Therefore, even if it is a simple shape such as a columnar shape or a plate shape, a concrete molded body having a difference in strength depending on the portion can be obtained without forming a notch or changing the thickness.

Also in the second material mixing method, when the amount of the mixed material is large and the container for mixing the mixed material is large, the ultrasonic wave is applied to a desired region by performing ultrasonic irradiation from a plurality of directions. Can be irradiated.

For example, when a chemical reaction is generated in a mixed material while mixing a solid material and a liquid material by using the second material mixing method, ultrasonic irradiation is performed from a plurality of directions, so that the entire reaction system is A chemical reaction can be caused by adjusting the concentration conditions.

According to the material mixing method as described above, it is possible to provide a material mixing method capable of reducing the anisotropy of the dense structure included in the mixed material.

The preferred embodiments according to the present invention have been described above, but it goes without saying that the present invention is not limited to such examples. The above-described example is an example, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples.

[1. Appearance observation]
First, in this example, the effect of the invention was confirmed by a model experiment.

In the following model experiment, after adjusting the solid-liquid mixed material, it is dried at room temperature and low humidity, the dried product is dried and broken, and the state of the breakage is observed, so that the anisotropic state in the solid-liquid mixed material is observed. Confirmed the density structure.

When a plastic-solid-liquid mixed material is dried, the material is dried while maintaining a close-packed structure, and a dry breakage occurs in the dried product. In the solid-liquid mixed material, since there are few solid materials in the “sparse” part, the corresponding part of the dried product also has a low density. Such a portion is more brittle and lower in strength than the portion corresponding to the “dense” portion of the solid-liquid mixed material in the dried product, and thus is easily cracked by drying shrinkage. Therefore, when the state of cracks after dry fracture is observed, it can be determined that the solid-liquid mixed material has a “sparse” portion corresponding to the cracks.

<Experiment 1>
Example 1
Calcium carbonate (Deer grade 1, manufactured by Kanto Chemical Co., Inc.) was used as the solid material, and pure water was used as the liquid material, and mixed to prepare a solid-liquid mixed material having a plurality of volume ratios.

Next, the obtained solid-liquid mixed material was directly put into a container of a container-type ultrasonic cleaner (SW5800, manufactured by Citizen, major axis diameter 148 mm, minor axis diameter 125 mm), and then a desktop shaker (FNX-220). , Manufactured by Tokyo Glass Instrument Co., Ltd.). The conditions for excitation were as follows.
<conditions>
Vibration frequency: 40 rpm, amplitude: 15 mm, vibration time: 1 minute

Next, the container type ultrasonic cleaner was driven to directly irradiate the solid-liquid mixed material in the container type ultrasonic cleaner with ultrasonic vibration. The conditions of ultrasonic irradiation were as follows.
<conditions>
Frequency: 42 kHz, irradiation time: 1 minute

After ultrasonic irradiation, the solid-liquid mixed material was dried at a temperature of 24 ° C. ± 1 ° C. and a humidity of 30% ± 10, and the dried product was dried and broken, and the state of the breaking was observed.

(Comparative Example 1)
Except not carrying out ultrasonic irradiation, it carried out similarly to Example 1, and dried and destroyed the dried material, and observed the mode of destruction.

FIG. 1A and FIG. 1B are photographs showing the appearance of cracks in the dried product. 1A shows the results of Example 1, and FIG. 1B shows the results of Comparative Example 1. In addition, the double arrows in the figure indicate the direction of horizontal excitation using a desktop shaker.

As shown in FIG. 1A, in the dried product of Example 1, cracks occurred isotropically. On the other hand, as shown in FIG. 1B, in the dried product of Comparative Example 1, striped cracks were formed in the direction orthogonal to the excitation direction. In Example 1, it was shown that the anisotropic dense structure inside the solid-liquid mixed material was reduced or eliminated by ultrasonic irradiation, and as a result, there was no dense structure enough to cause anisotropy during dry fracture. Seem.

<Experiment 2>
(Example 2)
Example 1 except that the solid material is calcium fluoride (Deer grade 1, manufactured by Kanto Chemical Co., Inc.), the liquid material is ethanol, the volume ratio is 20%, and the vibration frequency is 120 rpm. Then, the dried material was dried and broken, and the state of the breaking was observed.

Example 3
Drying was conducted in the same manner as in Example 1 except that the solid material was magnesium carbonate hydroxide (Deer grade 1, manufactured by Kanto Chemical Co., Ltd.), the volume ratio was 7.7%, and the vibration frequency was 120 rpm. The object was dried and destroyed, and the state of destruction was observed.

Example 4
Except that the volume ratio was 12.5%, the dried product was dried and broken in the same manner as in Example 3 to observe the state of destruction.

(Example 5)
The dried material was destroyed by drying in the same manner as in Example 1 except that the solid material was corn starch (special grade, manufactured by Wako Pure Chemical Industries, Ltd.), the volume ratio was 47.4%, and the vibration frequency was 60 rpm. We observed the state of destruction.

(Example 6)
The liquid material was a 0.1 mol / L aqueous solution of sodium chloride (special grade, manufactured by Kanto Chemical Co., Inc.), the volume ratio was 25%, and the frequency at the time of vibration was 99 rpm. The dried product was destroyed by drying and observed for destruction.

(Example 7)
Except that the volume ratio was 35%, the dried material was dried and broken in the same manner as in Example 6 to observe the state of destruction.

(Comparative Examples 2 to 7)
Except not carrying out ultrasonic irradiation, it carried out similarly to the corresponding Example, the dry thing was dried and destroyed, and the mode of destruction was observed.

The results of Examples 1 to 7 are shown in Table 1. In the table, the result of comparing the crack pattern of each example with the crack pattern of the corresponding comparative example is shown.

In the table, “A” in the result column indicates that the crack pattern in the corresponding comparative example disappeared and an isotropic crack pattern was observed. Further, “B” shown in the result column indicates that a crack pattern having a weak anisotropy was observed although a pattern similar to the crack pattern in the corresponding comparative example can be seen.

As a result of the evaluation, it was found that even if the solid material or liquid material was changed, the anisotropic dense structure inside the solid-liquid mixed material was reduced or eliminated by ultrasonic irradiation.

<Experiment 3>
FIG. 2 is a schematic diagram showing an experimental apparatus 100 used in Experiment 3. The experimental device 100 includes a vibration device 10 and an ultrasonic irradiation device 20.

The vibration device 10 includes a vibrator 11 placed on the base B, a stand 12 placed on the vibrator 11, and an arm 13 provided on the stand 12. . The ultrasonic irradiation device 20 includes an elevator 21, a water tank 22 placed on the elevator 21, and an ultrasonic vibrator 23 placed on the bottom surface of the water tank 22.

The shaker 11 uses a desktop shaker (FNX-220, manufactured by Tokyo Glass Instruments Co., Ltd.). The arm 13 provided on the stand 12 extends to the inside of the water tank 22 across the side wall of the water tank 22. A petri dish 1 for storing the solid-liquid mixed material is held at the tip of the arm 13.

The elevator 21 moves the water tank 22 and the ultrasonic transducer 23 up and down. Water W is stored in the water tank 22 up to a height of 38 cm from the bottom surface. Since the height of the ultrasonic transducer 23 is 8 cm, this situation corresponds to the case where the distance from the “surface of the ultrasonic transducer in which the ultrasonic wave is oscillated” to the water surface is 30 cm. The ultrasonic vibrator 23 has a specification in which the frequency can be changed. The ultrasonic vibration oscillated from the ultrasonic vibrator 23 propagates through the water W from the bottom surface side to the water surface side. In the figure, the propagation direction of the ultrasonic vibration is indicated by symbol β.

In such an experimental apparatus 100, first, the elevator 21 is lowered to store the solid-liquid mixed material in the petri dish 1 with the petri dish 1 separated from the water surface of the water W. When the vibrator 11 is moved in this state, the stand 12 reciprocates in the direction of the double arrow indicated by the symbol α in the drawing. Since the movement of the stand 12 is transmitted to the petri dish 1 through the arm 13, the petri dish 1 is vibrated in the direction of the double arrow indicated by the symbol α. Thereby, a solid-liquid mixed material is vibrated and a shearing force is applied.

Next, the vibrator 11 is stopped, and the elevator 21 is raised until the front bottom surface of the petri dish 1 comes into contact with the water surface of the water W while the solid-liquid mixed material in the petri dish 1 is left standing. In this state, the ultrasonic vibrator 23 is driven to propagate ultrasonic vibrations to the solid-liquid mixed material in the petri dish 1 through the water W.

(Example 8)
Using the experimental apparatus 100, the dried product was dried and broken to observe the state of destruction in the same manner as in Example 1 except that 37 kHz ultrasonic vibration was propagated to the solid-liquid mixed material.

Example 9
Except that the ultrasonic vibration of 71 kHz was propagated to the solid-liquid mixed material, the dried material was dried and broken to observe the state of breaking in the same manner as in Example 8.

(Example 10)
Except that 102 kHz ultrasonic vibration was propagated to the solid-liquid mixed material, the dried material was dried and broken to observe the state of destruction in the same manner as in Example 8.

(Comparative Example 8)
Except not carrying out ultrasonic irradiation, it carried out similarly to Example 8, and dried and destroyed the dried material, and observed the mode of destruction.

FIGS. 3A to 3D are photographs showing the state of cracks generated in the dried product. 3A shows the results of Example 8, FIG. 3B shows the results of Example 9, FIG. 3C shows the results of Example 10, and FIG. In addition, the double arrows in the figure indicate the direction of horizontal excitation.

As shown in FIGS. 3A to 3C, cracks areotropically occurred in the dried products of Examples 8 to 10. On the other hand, as shown in FIG. 3D, in the dried product of Comparative Example 8, striped cracks were formed in the direction orthogonal to the excitation direction. In Examples 8 to 10, it was shown that the anisotropic dense structure inside the solid-liquid mixed material was reduced or disappeared by ultrasonic irradiation, and as a result, there was no dense structure enough to cause anisotropy during dry fracture. It seems that there is.

[2. destruction strength]
Next, in this example, the effect of the invention was confirmed by measuring the breaking strength of the cement specimen.

(Example 11)
(A. Preparation of cement paste)
Water and cement containing sand (Toyo Materan Co., Ltd., instant cement (general purpose cement)) are weighed in a mass ratio of water: cement = 3: 10 and mixed for 1 minute. Produced. The instant cement used includes Portland cement, silica sand, and adhesive. The method for producing the cement paste is in accordance with the method described in the product bag of the cement with sand used.

(B. Cement paste filling)
Next, 48 g of cement paste was poured into a silicon container having a rectangular parallelepiped space of 76 mm × 27 mm × 30 mm. The silicon container was previously placed in a container of a container type ultrasonic cleaner (SW5800, manufactured by Citizen, major axis diameter 148 mm, minor axis diameter 125 mm) before filling with cement paste.

(C. Excitation to cement paste)
Next, using a shaker (manufactured by TAITEC, Triple Shaker NR-80), the cement paste was vibrated in the horizontal direction together with the silicon container and the container-type ultrasonic cleaner. The conditions for excitation were as follows.
<conditions>
Frequency: 60 rpm, amplitude: 15 mm in the length direction of the silicon container, excitation time: 1 minute

(D. Ultrasonic irradiation to cement paste)
After stopping the horizontal vibration, water was filled in the container of the container-type ultrasonic cleaner, the container-type ultrasonic cleaner was driven, and the solid-liquid mixed material in the container-type ultrasonic cleaner was directly irradiated with ultrasonic vibration. The conditions of ultrasonic irradiation were as follows.
<conditions>
Frequency: 42 kHz, irradiation time: 1 minute

(E. Solidification of cement paste)
After ultrasonic irradiation, the cement paste was stored at a temperature of 24 ° C. ± 1 ° C. and a humidity of 30% ± 10 and solidified to prepare a cement test piece. The obtained cement test piece was length: about 76 mm × width: about 27 mm × thickness: about 11 mm, and mass: about 40 g.

(Comparative Example 9)
A cement test piece of Comparative Example 9 was produced in the same manner as in Example 11 except that the above (d. Ultrasonic irradiation to cement paste) was not performed.

(Comparative Example 10)
A cement test piece of Comparative Example 10 was produced in the same manner as in Example 11 except that (c. Excitation to cement paste) and (d. Ultrasonic irradiation to cement paste) were not performed.

(Measurement of fracture strength)
The obtained cement test piece was measured for fracture strength by a three-point bending method using a tabletop precision universal testing machine (manufactured by Shimadzu Corp., Autograph AGS-X). Specifically, the solidified cement test piece was taken out from the silicon container, and the cement test piece taken out while maintaining the vertical vertical direction when solidified was installed in a testing machine, and the fracture strength was measured.

However, for the cement test piece of Comparative Example 10, the area where the indenter of the testing machine contacts on the surface of the test piece was processed so as to be flattened, and then the fracture strength was measured. The sanding is intended to remove unevenness in a region where the indenter contacts in order to prevent stress from the indenter from being concentrated locally.

About the influence of the sanding on the measured value of fracture strength, the cement test pieces of Example 11 and Comparative Example 9 were separately evaluated. By this evaluation, it was confirmed that the amount of application to the sample test piece of Comparative Example 10 did not affect the evaluation result of the fracture strength.

The measurement conditions for the fracture strength measurement were as follows.
<conditions>
Indenter tip radius: 5 mm, indenter tip width: 34 mm, fulcrum tip radius: 5 mm, fulcrum tip width: 34 mm, fulcrum distance (span): 50 mm, indenter descending speed: 1 mm / min

The fracture strength measurement was performed on ten cement test pieces whose length, width, thickness, and mass were measured. About each cement test piece, the arithmetic mean value (n = 10) of the maximum point stress (unit: N / mm < ² >) calculated | required was made into the fracture strength. Moreover, the standard deviation was calculated | required about the maximum point stress of each cement test piece.

The results of Example 11 and Comparative Examples 9 and 10 are shown in Table 2 and the graph of FIG. In the graph of FIG. 4, among the three points indicating the results of the examples and comparative examples, the central point indicates the average value of the results, and the upper and lower points indicate the standard deviation.

As a result of the evaluation, it was found that the fracture strength of Example 11 increased by 1.2 times compared with Comparative Example 9. In the cement test piece of Example 11, the anisotropic dense structure inside the cement paste was reduced or eliminated by ultrasonic irradiation. As a result, the inside became uniform compared to the cement test piece of Comparative Example 9, and the test stress was This seems to indicate that the “sparse” structure that is easy to concentrate has disappeared.

In addition, the difference in fracture strength between Comparative Example 9 and Comparative Example 10 is that bubbles in the cement paste are removed due to vibration, and the arch structure of the silica sand as an aggregate is collapsed. This is probably due to the decrease or disappearance of the sparse / dense structure.

From the above results, the usefulness of the present invention could be confirmed.

According to the material mixing method of this embodiment, the anisotropic structure (dense / dense structure) of the mixed material can be reduced or eliminated, and the internal structure of the mixed material can be easily uniformed. It is useful for mixing raw materials such as building materials such as concrete, cosmetics, paints, carbon materials and electronic materials in which inorganic fine particles are dispersed and mixed; foods in which organic materials are dispersed and mixed;
In a powder sintering method, a powder gypsum method, and an ink jet method 3D printer, particles such as powder constituting a modeled object are wet with a dispersion medium or a liquid resin before curing (before being completely cured). By implementing the material mixing method of this embodiment, micro anisotropy can be erased while maintaining the shape of the modeled object. In general, a modeled object obtained by a 3D printer has a layer structure, but by implementing the material mixing method of the present embodiment, it can be expected that the anisotropy between layers is eliminated and a stronger structure is obtained.
In addition, when a chemical reaction is generated while mixing materials using the material mixing method of the present embodiment, a uniform reaction can be expected, which is useful when mixing raw materials in a chemical plant.

DESCRIPTION OF SYMBOLS 10 ... Excitation apparatus, 11 ... Exciter, 12 ... Stand, 13 ... Arm, 20 ... Ultrasonic irradiation apparatus, 21 ... Elevator, 22 ... Water tank, 23 ... Ultrasonic vibrator, 100 ... Experimental apparatus, B ... Base Table, W ... Water, α ... Horizontal excitation direction, β ... Ultrasonic vibration propagation direction

Claims

Adding an external field to a mixed material prepared by mixing a particulate solid material and a liquid material, or a colloidal particle and a dispersion medium of the colloidal particle so that the volume ratio is not less than the liquid limit and not more than the plastic limit;
A step of propagating ultrasonic vibration having energy exceeding a yield stress of the mixed material after the mixed material is allowed to stand;
The material mixing method according to claim 1, wherein the external field is a dynamic external field.
The particulate solid material is a dielectric or magnetic material;
The material mixing method according to claim 1, wherein the external field is an electromagnetic external field.
While mixing the particulate solid material and the liquid material, or the colloidal particles and the dispersion medium of the colloidal particles so that the volume ratio is not less than the liquid limit and not more than the plastic limit, the mixing is performed inside the obtained mixed material. A material mixing method comprising a step of propagating ultrasonic vibrations having energy exceeding a material yield stress.
In the state where the mixed material obtained by mixing the particulate solid material and the liquid material, or the colloidal particles and the dispersion medium of the colloidal particles so that the volume ratio is higher than the liquid limit and lower than the plastic limit, A material mixing method comprising a step of propagating ultrasonic vibration having energy exceeding the yield stress of the mixed material in the mixed material.
The material mixing method according to any one of claims 1 to 5, wherein in the step of propagating the ultrasonic vibration, the ultrasonic vibration is propagated from a plurality of directions with respect to the mixed material.