TWI693098B - Dispersing device and method - Google Patents

Abstract

Provided is a dispersing device and a dispersing method for dispersing solid materials more finely, wherein a dispersing device (10) for dispersing solid materials contained in a processing liquid by a pressurized processing liquid through a nozzle (24) is characterized by Is: the nozzle (24) is on the first axis (X) orthogonal to the traveling direction (F) of the processing liquid, and the overall flow velocity of the nozzle (24) is substantially fixed; in the direction of the traveling direction (F) And the second axis (Y) orthogonal to the first axis (X), the flow velocity in the center of the nozzle (24) is faster.

Description

Dispersing device and method

The invention relates to a dispersion device and a dispersion method.

As a device for finely dispersing a solid substance, a dispersing device is known which supplies a shear stress to a processing liquid containing a solid substance and finely disperses the solid substance by the shear stress (for example, Patent Document 1). The dispersing device of Patent Document 1 disperses the solid matter in the slurry finely by passing the slurry through a nozzle in a state where a pressure of 150 MPa is applied, and applying a shear stress to the slurry.

【Advanced Patent Literature】 【Patent Literature】

[Patent Document 1] Japanese Unexamined Patent Publication No. 2007-224997

The dispersing device can disperse, for example, a bundle of carbon nanotubes (hereinafter referred to as "CNT") as solid materials.

In the nozzle, in order to supply a large shear stress to the CNT, it is effective to use a CNT-containing high-viscosity treatment liquid or use a nozzle having a small nozzle diameter. However, in the case of using a processing solution with a high viscosity or a nozzle with a small nozzle diameter, there is a problem that the CNT is clogged in the nozzle.

In addition, it is also conceivable to gradually disperse the CNTs by passing the processing liquid in multiple stages to a plurality of nozzles that gradually reduce the nozzle diameter. However, since the processing liquid is passed through the nozzle in multiple stages, there is a problem that the CNT is rectangularized.

Therefore, an object of the present invention is to provide a dispersing device and a dispersing method that can disperse solid materials finer.

The dispersing device of the present invention is a dispersing device for dispersing the solid matter contained in the processing liquid by pressurized processing liquid through a nozzle, characterized in that the nozzle is: orthogonal to the traveling direction of the processing liquid On the first axis, the overall flow rate of the nozzle is substantially fixed; on the second axis orthogonal to the direction of travel and the first axis, the flow rate at the center of the nozzle is faster.

The dispersion method of the present invention includes a step of passing a pressurized processing liquid through a nozzle, and dispersing the solid matter contained in the processing liquid, characterized in that the processing liquid is passed through a nozzle, and the nozzle is in contact with the In the first axis orthogonal to the traveling direction of the processing liquid, the overall flow velocity in the nozzle is substantially fixed, and in the second axis orthogonal to the traveling direction and the first axis, the velocity in the center of the nozzle is faster.

According to the present invention, the processing liquid is supplied with a large shear stress near the plane parallel to the plane including the second axis and the traveling direction, and the processing liquid is caused near the plane parallel to the plane including the first axis and the traveling direction F. The received shear stress becomes smaller, thereby allowing the processing liquid to smoothly pass through. As a result, as a whole of the nozzle, the solid matter contained in the processing liquid can be prevented from clogging in the flow path, and the solid matter can be dispersed more finely.

10‧‧‧Dispersing device

16A~16D‧‧‧Nozzle

24, 30, 32, 34 ‧‧‧ nozzle

26、36‧‧‧Inner surface of the 1st axis X side

28, 38‧‧‧ 2nd axis Y side inner surface

D‧‧‧Distance between the inner surfaces of the X side of the 1st axis

F‧‧‧ Direction of travel

H‧‧‧Distance between the inner surfaces of the Y side of the 2nd axis

X‧‧‧ 1st axis

Y‧‧‧ 2nd axis

Fig. 1 is a schematic diagram showing the configuration of the dispersing device of this embodiment.

FIG. 2 is a front view showing the configuration of the nozzle of this embodiment.

FIG. 3 is a diagram showing the configuration of the nozzle of the present embodiment, FIG. 3A is a horizontal cross-sectional view, and FIG. 3B is a vertical cross-sectional view.

Fig. 4 is a front view showing the configuration of a nozzle of modification (1).

Fig. 5 is a front view showing the configuration of the nozzle of the modification (2).

Fig. 6 is a front view showing the configuration of a nozzle of modification (3).

Fig. 7 shows a model of the nozzle used in the simulation, Fig. 7A is a front view, and Fig. 7B is a perspective view.

FIG. 8 is a distribution diagram showing the simulation result of the flow velocity distribution of the embodiment. FIG. 8A is the result of the first embodiment, FIG. 8B is the second embodiment, and FIG. 8C is the result of the third embodiment.

FIG. 9 is a graph showing the simulation results of the flow velocity distribution of the embodiment, and FIG. 9A is the result of the X axis and FIG. 9B is the result of the Y axis.

FIG. 10 is a distribution diagram showing the simulation result of the flow velocity distribution of the comparative example, FIG. 10A is the result of the first comparative example, and FIG. 10B is the result of the second comparative example.

Fig. 11 is a graph showing the simulation result of the flow velocity distribution of the comparative example, and Fig. 11A is the result of the X axis and Fig. 11B is the result of the Y axis.

FIG. 12 is a diagram showing the simulation result of the speed vector in the first embodiment, and FIG. 12A is the result of the FX cross section and FIG. 12B is the YF cross section.

Fig. 13 is a diagram showing the simulation results of the speed vector of the comparative example, Fig. 13A is the FX section of the first comparative example, Fig. 13B is the YF section of the first comparative example, and Fig. 13C is the FX of the second comparative example Section, the second comparison of the 13D graph series Example of YF profile results.

FIG. 14 is a distribution diagram showing the simulation result of the shear velocity distribution of the embodiment. FIG. 14A is the result of the first embodiment, FIG. 14B is the second embodiment, and FIG. 14C is the result of the third embodiment.

Fig. 15 is a graph showing the simulation results of the shear velocity distribution of the embodiment, and Fig. 15A is the result of the X axis and Fig. 15B is the result of the Y axis.

Fig. 16 is a distribution diagram showing the simulation result of the shear velocity distribution of the comparative example, and Fig. 16A is the result of the first comparative example and Fig. 16B is the result of the second comparative example.

Fig. 17 is a graph showing the simulation result of the shear velocity distribution of the comparative example, and Fig. 17A is the result of the X axis and Fig. 17B is the result of the Y axis.

Figure 18 is a graph showing the results of calculating the area ratio of the high shear rate area. Figure 18A is the first example, Figure 18B is the second example, Figure 18C is the third example, and Figure 18D is the figure. The first comparative example and FIG. 18E are the results of the second comparative example.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(Overall composition)

The dispersion device 10 shown in FIG. 1 includes a compressor 12, a processing liquid supply unit 14, a nozzle unit 16A, and a cooling unit 18. The compressor 12 is connected to the processing liquid supply unit 14 via a check valve 22. The compressor 12 is connected to the power 20, and the discharge port is connected to one side of the compression pipe 21. The other side of the compression pipe 21 is connected to the inlet of the nozzle portion 16A. The outlet of the nozzle portion 16A is connected to one side of the discharge pipe 23. The other side of the discharge pipe 23 is connected to the cooling unit 18. The dispersion device 10 passes the nozzle through the processing liquid supplied from the processing liquid supply portion 14 The portion 16A is formed by dispersing the solid matter contained in the treatment liquid.

The nozzle portion 16A is formed of a cylindrical member as shown in FIG. 2 and has a nozzle 24 through which the processing liquid passes. The nozzle 24 system flow path is formed to be finer than the inner diameter of the compression pipe 21. The nozzle 24 is opened parallel to the traveling direction F of the processing liquid, and has a flow velocity distribution at a first axis X orthogonal to the traveling direction F and a second axis Y orthogonal to the traveling direction F and the first axis X Formed in different ways. That is, the nozzle 24 is formed in such a manner that the overall flow rate of the nozzle 24 on the first axis X is substantially constant, and the flow rate of the center of the nozzle 24 on the second axis Y becomes faster. In addition, for convenience of explanation, the traveling direction F is regarded as passing through the center of the nozzle 24.

In the case of this embodiment, the nozzle 24 has an oval shape. Thereby, the distance D between the inner surfaces of the first axis X side of the nozzle 24 system is formed longer than the distance H between the inner surfaces of the second axis Y side. The distance D between the inner surfaces 26 on the first axis X side can be set to, for example, 50 to 300 μm, preferably 50 to 200 μm. If the distance between the inner surfaces 28 on the Y-axis of the second axis is regarded as H, the ratio D/H of the distance D between the inner surfaces of the X-axis on the first axis can be set to 1.5-16, preferably 2-8, 2~4 is better.

(Action and effect)

Next, the operation and effects of the dispersing device 10 configured as described above will be described. First, the processing liquid is poured into the processing liquid supply unit 14. The treatment liquid contains a dispersion medium and a solid substance. From the viewpoint of obtaining a large shear stress, the treatment liquid system preferably has a viscosity exceeding 1 (mPa‧s), and more preferably exceeding 100 (mPa‧s).

As the dispersion medium, for example, a resin and a solvent as a coating film formation substance are included. For example, the dispersion medium may be made of polyimide (PI) as a resin and NMP (N-methyl-2-pyrrolidone) as a solvent. Also, the media system can be dispersed It is made of polyvinylpyrrolidone (PVP) as a resin and water as a solvent. Furthermore, the dispersion medium may be made of polyimide (PAI) as a resin and NMP as a solvent.

For solid-state components with an aspect ratio exceeding 10, for example, CNT or carbon nanofibers, silver nanofibers, inorganic nanofibers, cellulose nanofibers, carbon fiber, etc. can be used. In addition, it is preferable to use a solid substance with an aspect ratio exceeding 50. In this case, the solid state system is, for example, 10 nm in diameter × 0.5 μm in length.

The compressor 12 is driven by the connected power 20 to press out the processing liquid supplied from the processing liquid supply unit 14. The pressed processing liquid passes through the compression pipe 21 and reaches the nozzle portion 16A. The nozzle 24 is formed to have a flow path finer than the inner diameter of the compression pipe 21, and the pressure of the processing liquid is 10 to 200 MPa immediately before the nozzle 24

When the processing liquid passes through the nozzle 24, it becomes a high-speed flow. Due to passing through the nozzle 24, the processing liquid system is subjected to a large shear stress. The solid matter contained in the processing liquid is dispersed more finely due to this shear stress. In this way, a dispersion liquid in which the solid matter is dispersed more finely is produced. The dispersion liquid immediately after passing through the nozzle 24 is at a high temperature. The dispersing device supplies the dispersion liquid to the cooling unit 18 via the discharge pipe 23 and cools the dispersion liquid to a predetermined temperature before discharging.

In the case of this embodiment, the nozzle 24 is formed into an ellipse, and as shown in FIGS. 3A and B, the velocity distribution on the first axis X and the second axis Y are different. That is, in the first axis X, the flow velocity is substantially constant over the entire flow rate of the nozzle 24 (FIG. 3A ). Therefore, the shear rate (also referred to as velocity slope) of the processing liquid system near the first axis X is small. By this, the processing liquid is in a region where the shear rate is small, that is, near the plane parallel to the plane including the first axis X and the traveling direction F. Shear stress small. Therefore, the solid matter contained in the processing liquid passes through the nozzle 24 smoothly without clogging near a plane parallel to the plane including the first axis X and the traveling direction F.

On the other hand, on the second axis Y, the flow velocity is faster in the center of the nozzle 24 (FIG. 3B). That is, the processing liquid system has a high shear rate near the second axis Y. As a result, the treatment liquid and the solid matter contained in the treatment liquid are subjected to a large shear speed area (high shear speed area), that is, near the plane parallel to the plane including the second axis Y and the traveling direction F Shear stress. With this shear stress, the solid system is dispersed more finely.

As described above, in the case of this embodiment, the solid matter reaching the inlet of the nozzle 24 is dispersed more finely by receiving a large shear stress near a plane parallel to the plane including the second axis Y and the traveling direction F . The solid material system can smoothly pass through the nozzle 24 by changing the direction to a direction parallel to the first axis X even if the flow path in the nozzle 24 is clogged by receiving a large shear stress.

In this way, the nozzle 24 is provided with a large shear stress on the processing liquid near a plane parallel to the plane including the second axis Y and the traveling direction F, and a plane parallel to the plane including the first axis X and the traveling direction F. In the vicinity of the surface, the shear stress on the processing liquid is small, so the processing liquid passes smoothly.

Therefore, the dispersing device 10 as the entire nozzle 24 prevents the solid matter contained in the processing liquid from clogging the flow path, and disperses the solid matter more finely.

(Modification)

The present invention is not limited to this embodiment, and can be appropriately changed within the scope of the gist of the present invention.

For example, in the case of this embodiment, it is explained that the nozzle 24 has In the case of an ellipse, the present invention is not limited to this. It may be a hexagonal nozzle 30 (FIG. 4) with a long lateral length in a direction parallel to the first axis X, or a nozzle 32 with a laterally long rectangular shape ( (Figure 5). Because the nozzle portions 16B, 16C shown in FIGS. 4 and 5 are substantially fixed at the overall flow velocity of the nozzles 30, 32 on the first axis X, and the nozzles 30, 32 on the second axis Y Since the flow velocity in the center is formed in a faster manner, the same effect as in this embodiment can be obtained.

Also, as shown in Fig. 6, a circular nozzle 34 may be used. In this case, the nozzle is formed so that the friction force between the first axis X-side inner surface 36 and the processing liquid is smaller than the second axis Y-side inner surface 38. For example, the nozzle 34 may use the first axis X side inner surface 36 to be kept at a higher temperature than the second axis Y side inner surface 38. In addition, the nozzle 34 may be formed so that the roughness of the inner surface 36 on the first axis X side is smaller than the inner surface 38 on the second axis Y side. Furthermore, the nozzle 34 may be formed so that the first axis X-side inner surface 36 has a non-affinity for the processing liquid.

By including the nozzle 34 formed in this way, the overall flow velocity of the nozzle portion 16D at the first axis X at the nozzle 34 is substantially fixed, and the flow velocity at the center of the nozzle 34 at the second axis Y becomes faster Formed in the same manner as above, so that the same effects as in this embodiment can be obtained.

(simulation)

The flow of fluid in the nozzle is obtained by simulation. The Reynolds number (Re) can be obtained by the following mathematical formula (1).

Re=(ρ‧u‧D)/μ...(1)

Among them, ρ: density (kg/m ³ ), u: average flow rate (m/s), D: diameter of round tube (mm), μ: viscosity (Pa‧s) When Re<2000, the fluid flow can be regarded as laminar flow.

Here, if the average flow velocity u is m: weight flow (kg/s), A: cross-sectional area (m ² ), it can be obtained by the following mathematical formula (2).

u=m/(ρA)...(2)

The flow velocity u(r) at the radial position r of the fluid flowing in the circular tube of radius R can be obtained by the following mathematical formula (3).

u(r)=2u{1-(r/R) ² }...(3)

The shear rate γ(r) at the position r in the radial direction can be obtained by the following mathematical formula (4).

γ(r)=| du/dr |=4ur/R ² ... (4)

In addition, the shear stress τ has a relationship of τ=μ‧(du/dr)=μγ(r).

(model)

The flow system is regarded as an uncompressed Newtonian fluid, and it is assumed that NMP (N-methyl-2-pyrrolidone) contains a solution of PI (polyimide) 8.5 wt% (density ρ: 1052 kg/m ³ ), viscosity μ : 0.26Pa‧s) for calculation. The nozzle shape is as shown in Figs. 7A and B, and a nozzle whose front shape is elliptical is adopted. The first table shows the dimensions of each part. As a comparative example, two types of nozzles that have a true circular shape and different diameters are calculated.

(Calculation results)

FIGS. 8A to C and FIGS. 9A and B show the simulation results of the flow velocity distribution of the nozzles of the first to third embodiments. In FIGS. 9A and 9B, the vertical axis represents the flow velocity reaching rate (%) when the maximum flow velocity is 100, and the horizontal axis represents the position in the X-axis or Y-axis direction. Figures 10A and B and 11A and B are the simulation results of the first and second comparative examples. From this figure, it is confirmed that the nozzles of the first to third embodiments are different in the X-axis and Y-axis, the flow velocity distribution is different, and the X-axis has a fixed speed area. On the other hand, the nozzles of the first and second comparative examples have the same flow velocity distribution on the X axis and the Y axis.

FIGS. 12A and B show the velocity vector from the nozzle inlet to 0.5 mm of the nozzle of the first embodiment. Figures 13A~D are the velocity vectors of the first and second comparative examples.

FIGS. 14A to C and FIGS. 15A and B show the simulation results of the shear velocity distribution of the nozzles of the first to third embodiments. In FIGS. 15A and 15B, the vertical axis represents the shear rate (1/s), and the horizontal axis represents the position in the X-axis or Y-axis direction. Figures 16A and B and Figures 17A and B are simulation results of the first and second comparative examples. From this figure, it is confirmed that the nozzles of the first to third embodiments are different in the distribution state of the shear speed between the X axis and the Y axis, and there is an area where the shear speed is fixed on the X axis. On the other hand, the nozzles of the first and second comparative examples have the same shear velocity distribution on the X axis and the Y axis.

Table 2 shows the results of the area ratio of the high shear rate area. In addition, Figs. 18A to E show a region of high shear rate when the shear rate is 1 × 10 ⁷ (1/s). From this figure, because the nozzles of the first to third embodiments are wide in the area of high shear rate (black part in Figure 18), furthermore, the region of low shear rate (white part in Figure 18) is also formed It is wide, so it can be said that as the entire nozzle, the solid matter contained in the treatment liquid is prevented from clogging in the flow path, and the solid matter is dispersed more finely.

On the other hand, in the first comparative example, since the inner diameter of the nozzle is large, since the area of the high shear rate region is narrow and almost occupied by the region of low shear rate, it can be said that it is difficult to efficiently disperse the solid matter. In addition, in the second comparative example, although the area of the high shear rate area is wide, the area where the shear rate is small is narrow, so it can be said that the solid matter is easily blocked in the flow path.

16A‧‧‧Nozzle

24‧‧‧ nozzle

26‧‧‧Inner surface of the 1st axis X side

28‧‧‧Inner surface of the 2nd axis Y side

X‧‧‧ 1st axis

Y‧‧‧ 2nd axis

F‧‧‧ Direction of travel

D‧‧‧Distance between the inner surfaces of the X side of the 1st axis

H‧‧‧Distance between the inner surfaces of the Y side of the 2nd axis

Claims (5)

A dispersing device that disperses the solid matter contained in the processing liquid by pressurized processing liquid through a nozzle, characterized in that the nozzle is: a cylindrical member that opens parallel to the direction of travel of the processing liquid ; The distance D between the inner surfaces on the side of the first axis orthogonal to the direction of travel is formed longer than the distance H between the inner surfaces on the side of the second axis orthogonal to the direction of travel and the first axis, The distance D is 50 to 300 μm, and the ratio D/H of the distance D to the distance H is 1.5 to 16; on the first axis, the flow rate of the treatment liquid is substantially fixed throughout the nozzle; on the second axis The flow velocity of the treatment liquid in the center of the nozzle is faster than the flow velocity of the treatment liquid at the end of the nozzle. A dispersing device is a dispersing device that disperses the solid matter contained in the processing liquid by pressurized processing liquid through a nozzle, and is characterized in that the nozzle is: the first is orthogonal to the traveling direction of the processing liquid The inner surface on the side of the one axis is maintained at a higher temperature than the inner surface on the side of the second axis orthogonal to the traveling direction and the first axis; on the first axis, the flow rate of the processing liquid is roughly the entire nozzle Fixed; on the second axis, the flow rate of the treatment liquid in the center of the nozzle is faster than the flow rate of the treatment liquid at the end of the nozzle. A dispersing device is to make the place by pressurized processing liquid through the nozzle The dispersing device for dispersing the solid matter contained in the processing liquid is characterized in that the nozzle system has a roughness of the inner surface on the side of the first axis orthogonal to the traveling direction of the processing liquid The inner surface on the side of the second axis orthogonal to the first axis is small; on the first axis, the flow rate of the treatment liquid is substantially fixed throughout the nozzle; on the second axis, the treatment liquid at the center of the nozzle The flow rate is faster than the flow rate of the treatment liquid at the end of the nozzle. A dispersing device is a dispersing device that disperses the solid matter contained in the processing liquid by the pressurized processing liquid passing through a nozzle, characterized in that the nozzle is: the first orthogonal to the traveling direction of the processing liquid The inner side of the shaft has a non-affinity for the treatment liquid; on the first axis, the flow rate of the treatment liquid is substantially fixed throughout the nozzle; on the second axis, the treatment liquid at the center of the nozzle The flow rate is faster than the flow rate of the treatment liquid at the end of the nozzle. A dispersion method including the step of passing the pressurized processing liquid through a nozzle and dispersing the solid matter contained in the processing liquid, characterized in that the nozzle is a cylindrical member parallel to the traveling direction of the processing liquid The ground is opened, and the distance D between the inner surfaces of the side of the first axis orthogonal to the direction of travel is formed to be greater than that of the side of the second axis orthogonal to the direction of travel and the first axis The distance H between the inner surfaces is long, the distance D is 50 to 300 μm, and the ratio D/H of the distance D to the distance H is 1.5 to 16; at the nozzle, the flow rate of the treatment liquid on the first axis is The entirety of the nozzle is substantially fixed, and the flow rate of the processing liquid on the second axis and the center of the nozzle is faster than the flow rate of the processing liquid at the end of the nozzle to pass the processing liquid.

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