JP6494983B2 - Dispersing apparatus and dispersing method - Google Patents

Description

  The present invention relates to a dispersion apparatus and a dispersion method.

  As a device for finely dispersing a solid material, there is known a dispersion device that applies a shear stress to a treatment liquid containing a solid material and finely disperses the solid material by the shear stress (for example, Patent Document 1). The dispersing device of Patent Document 1 applies a shear stress to the slurry by passing the slurry through a nozzle in a state where a pressure of 150 MPa is applied, and finely disperses the solid matter in the slurry.

JP 2007-224997 A

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

  In order to give a large shear stress to the CNT in the nozzle, it is effective to use a treatment liquid containing CNT and having a high viscosity or a nozzle having a small nozzle diameter. However, when a treatment liquid having a high viscosity or a nozzle having a small nozzle diameter is used, there is a problem that the CNT is clogged.

  Another possible method is to gradually disperse CNTs by passing the treatment liquid in multiple stages through a plurality of nozzles whose nozzle diameters are reduced stepwise. However, there has been a problem that the length of the CNT is shortened by passing the treatment liquid through the nozzles in multiple stages.

  Then, an object of this invention is to provide the dispersion apparatus and dispersion method which can disperse | distribute a solid substance more finely.

  The dispersing apparatus according to the present invention is a dispersing apparatus that disperses the solid matter contained in the processing liquid by passing the pressurized processing liquid through the nozzle, and the nozzle is orthogonal to the traveling direction of the processing liquid. In the first axis, the flow velocity of the entire nozzle is substantially constant, and in the second axis perpendicular to the traveling direction and the first axis, the center of the nozzle has a higher flow velocity.

  The dispersion method according to the present invention includes a step in which a pressurized treatment liquid passes through a nozzle, and in the dispersion method for dispersing solid matter contained in the treatment liquid, a first axis orthogonal to the traveling direction of the treatment liquid. The flow rate of the entire nozzle is substantially constant, and the processing liquid is passed through a nozzle having a higher flow rate at the center of the nozzle in the traveling direction and the second axis orthogonal to the first axis. To do.

  According to the present invention, the processing liquid is applied in the vicinity of the plane parallel to the plane including the first axis and the traveling direction, while applying a large shear stress to the processing liquid in the vicinity of the plane parallel to the plane including the second axis and the traveling direction. By reducing the shear stress to be received, the treatment liquid is passed smoothly. Thereby, the solid matter can be more finely dispersed while preventing the solid matter contained in the processing liquid from clogging the flow path as the whole nozzle.

It is a schematic diagram which shows the structure of the dispersion apparatus which concerns on this embodiment. It is a front view which shows the structure of the nozzle which concerns on this embodiment. It is a figure which shows the structure of the nozzle which concerns on this embodiment, FIG. 3A is a cross-sectional view, FIG. 3B is a longitudinal cross-sectional view. It is a front view which shows the structure of the nozzle which concerns on a modification (1). It is a front view which shows the structure of the nozzle which concerns on a modification (2). It is a front view which shows the structure of the nozzle which concerns on a modification (3). The model of the nozzle used for simulation is shown, FIG. 7A is a front view, FIG. 7B is a perspective view. FIG. 8A is a distribution diagram showing a simulation result of a flow velocity distribution according to an example. FIG. 8A shows the result of Example 1, FIG. 8B shows the result of Example 2, and FIG. It is a graph which shows the simulation result of the flow-velocity distribution which concerns on an Example, FIG. 9A is a X-axis result, FIG. 9B is a Y-axis result. FIG. 10A is a distribution diagram showing a simulation result of a flow velocity distribution according to a comparative example. FIG. 10A shows a result of Comparative Example 1 and FIG. 10B shows a result of Comparative Example 2. It is a graph which shows the simulation result of the flow-velocity distribution which concerns on a comparative example, FIG. 11A is a result of an X-axis, FIG. 11B is a result of a Y-axis. It is a figure which shows the simulation result of the velocity vector based on Example 1, FIG. 12A is a FX cross section, FIG. 12B is a result of a YF cross section. FIG. 13A is a view showing a simulation result of a velocity vector according to a comparative example, FIG. 13A is an FX cross section of Comparative Example 1, FIG. 13B is a YF cross section of Comparative Example 1, FIG. 13C is an FX cross section of Comparative Example 2, and FIG. It is a result of 2 YF cross sections. FIG. 14A is a distribution diagram showing a simulation result of a shear rate distribution according to an example. FIG. 14A shows the result of Example 1, FIG. 14B shows the result of Example 2, and FIG. It is a graph which shows the simulation result of the shear rate distribution which concerns on an Example, FIG. 15A is a X-axis result, FIG. 15B is a Y-axis result. FIG. 16A is a distribution diagram showing a simulation result of a shear rate distribution according to a comparative example. FIG. 16A is a result of Comparative Example 1, and FIG. It is a graph which shows the simulation result of the shear rate distribution which concerns on a comparative example, FIG. 17A is a X-axis result, FIG. 17B is a Y-axis result. FIG. 18A is a diagram showing the results of calculating the area ratio of the high shear rate region, FIG. 18A is Example 1, FIG. 18B is Example 2, FIG. 18C is Example 3, FIG. 18D is Comparative Example 1, and FIG. The result of 2.

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

(overall structure)
The dispersion apparatus 10 illustrated in FIG. 1 includes a compressor 12, a processing liquid supply unit 14, a nozzle unit 16A, and a cooling unit 18. A processing liquid supply unit 14 is connected to the compressor 12 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 entrance of the nozzle portion 16A. The outlet of the nozzle portion 16 </ b> A 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 is formed so that the treatment liquid supplied from the treatment liquid supply unit 14 can disperse solid matter contained in the treatment liquid by passing through the nozzle portion 16A.

  As shown in FIG. 2, the nozzle portion 16 </ b> A is formed of a cylindrical member and has a nozzle 24 through which the processing liquid passes. The nozzle 24 has a finer flow path than the inner diameter of the compression pipe 21. The nozzle 24 opens in parallel with the traveling direction F of the processing liquid, and in the first axis X orthogonal to the traveling direction F and the second axis Y orthogonal to the traveling direction F and the first axis X, The flow velocity distribution is different. That is, the nozzle 24 is formed so that the flow velocity of the entire nozzle 24 is substantially constant on the first axis X, and the center of the nozzle 24 is faster on the second axis Y. For convenience of explanation, it is assumed that the traveling direction F passes through the center of the nozzle 24.

  In the present embodiment, the nozzle 24 has an oval shape. Accordingly, the nozzle 24 is formed such that the distance D between the first axis X side inner surfaces is longer than the distance H between the second axis Y side inner surfaces. The distance D between the first axis X-side inner surfaces can be, for example, 50 to 300 μm, preferably 50 to 200 μm. If the distance between the inner surfaces of the second axis Y side is H, the ratio D / H to the distance D between the inner surfaces of the first axis X side is 1.5 to 16, preferably 2 to 8, more preferably 2 to 4. It can be.

(Operation and effect)
Next, the operation and effect of the dispersion apparatus 10 configured as described above will be described. First, the processing liquid is charged into the processing liquid supply unit 14. The treatment liquid includes a dispersion medium and a solid material. From the viewpoint of obtaining a large shear stress, the treatment liquid preferably has a viscosity exceeding 1 (mPa · s), and more preferably exceeds 100 (mPa · s).

  Examples of the dispersion medium include a resin as a coating film formed product and a solvent. For example, the dispersion medium may be made of polyimide (PI) as a resin and NMP (N-methyl-2-pyrrolidone) as a solvent. The dispersion medium may be made of polyvinyl pyrrolidone (PVP) as a resin and water as a solvent. Further, the dispersion medium may be made of polyamideimide (PAI) as a resin and NMP as a solvent.

  As the solid material, a member having an aspect ratio exceeding 10 such as CNT, carbon nanofiber, silver nanowire, inorganic nanotube, cellulose nanofiber, and carbon fiber can be used. Further, it is preferable to use a solid having an aspect ratio exceeding 50. In this case, the solid is, for example, 10 nm in diameter × 0.5 μm in length.

  The compressor 12 is driven by the connected power 20 to push out the processing liquid supplied from the processing liquid supply unit 14. The extruded processing liquid reaches the nozzle portion 16 </ b> A through the compression pipe 21. The nozzle 24 has a finer flow path than the compression pipe 21, so that 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. By passing through the nozzle 24, the treatment liquid is subjected to a large shear stress. The solid contained in the treatment liquid is more finely dispersed by the shear stress. In this way, a dispersion in which the solid matter is more finely dispersed is produced. The dispersion immediately after passing through the nozzle 24 is at a high temperature. The dispersion apparatus can supply the dispersion liquid to the cooling unit 18 through the discharge pipe 23, cool the dispersion liquid to a predetermined temperature, and then discharge the dispersion liquid.

  In the present embodiment, the nozzle 24 is formed in an oval shape, so that the flow velocity distribution differs between the first axis X and the second axis Y as shown in FIG. That is, on the first axis X, the flow velocity is substantially constant throughout the nozzle 24 (FIG. 3A). Therefore, the treatment liquid has a low shear rate (also referred to as a velocity gradient) in the vicinity of the first axis X. As a result, the treatment liquid receives a small shear stress in a region where the shear rate is low, that is, in the vicinity of a plane parallel to the plane including the first axis X and the traveling direction F. Therefore, the solid matter contained in the treatment liquid smoothly passes through the nozzle 24 without clogging in the vicinity of 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 at the center of the nozzle 24 (FIG. 3B). That is, the treatment liquid has a high shear rate in the vicinity of the second axis Y. As a result, the treatment liquid and the solid contained in the treatment liquid are subjected to a large shear stress in a region where a high shear rate is generated (high shear rate region), that is, in the vicinity of a plane parallel to the plane including the second axis Y and the traveling direction F. . The solid matter is more finely dispersed by this shear stress.

  As described above, in the case of the present embodiment, the solid matter that has reached the inlet of the nozzle 24 is more finely dispersed by receiving a large shear stress in the vicinity of the plane parallel to the plane including the second axis Y and the traveling direction F. . Even if the solid matter is clogged in the flow path of the nozzle 24 by receiving a large shear stress, it can smoothly pass through the nozzle 24 by changing the direction in a direction parallel to the first axis X. .

  As described above, the nozzle 24 applies a large shear stress to the treatment liquid in the vicinity of the plane parallel to the plane including the second axis Y and the traveling direction F, and near the plane parallel to the plane including the first axis X and the traveling direction F. Since the shear stress that the treatment liquid receives is small, the treatment liquid is passed smoothly.

  Therefore, the dispersion apparatus 10 can disperse the solid matter more finely while preventing the solid matter contained in the processing liquid from clogging the flow path as the entire nozzle 24.

(Modification)
The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the gist of the present invention.

  For example, in the above embodiment, the case where the nozzle 24 has an oval shape has been described. However, the present invention is not limited to this, and the horizontally long hexagonal nozzle 30 that is long in the direction parallel to the first axis X (FIG. 4). Or a horizontally long rectangular nozzle 32 (FIG. 5). The nozzle portions 16B and 16C shown in FIGS. 4 and 5 have a substantially constant flow rate across the nozzles 30 and 32 on the first axis X, and the center of the nozzles 30 and 32 on the second axis Y is centered. Since it is formed so that the flow velocity becomes faster, the same effect as the above embodiment can be obtained.

  Alternatively, a circular nozzle 34 may be used as shown in FIG. In this case, the nozzle is formed so that the friction force between the first axis X-side inner surface 36 and the treatment liquid is smaller than that of the second axis Y-side inner surface 38. For example, the nozzle 34 may hold the first axis X-side inner surface 36 at a higher temperature than the second axis Y-side inner surface 38. Further, the nozzle 34 may be formed such that the first axis X-side inner surface 36 has a smaller roughness than the second axis Y-side inner surface 38. Further, the nozzle 34 may form the first axis X-side inner surface 36 so as to have no affinity for the processing liquid.

  By providing the nozzle 34 formed in this way, the nozzle portion 16D has a substantially constant flow velocity across the nozzle 34 in the first axis X, and the center of the nozzle 34 in the second axis Y is more central. Since it is formed so as to increase the flow velocity, the same effect as in the above embodiment can be obtained.

(simulation)
The fluid flow in the nozzle was determined by simulation. The Reynolds number (Re) can be obtained by the following formula (1).
Re = (ρ · u · D) / μ (1)

However, ρ: density (kg / m ³ ), u: average flow velocity (m / s), D: circular tube diameter (mm), μ: viscosity (Pa · s). When Re <2000, the fluid flow can be regarded as a laminar flow.

Here, the average flow velocity u can be obtained by the following equation (2) where m: weight flow rate (kg / s) and A: cross-sectional area (m ² ).
u = m / (ρA) (2)

The flow velocity u (r) at the position r in the radial direction of the fluid flowing through the circular pipe having the radius R can be obtained by the following equation (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 equation (4).
γ (r) = | du / dr | = 4 ur / R ² (4)

  Further, the shear stress τ has a relationship of τ = μ · (du / dr) = μγ (r).

(model)
The fluid is an incompressible Newtonian fluid, a solution containing 8.5 wt% of PI (polyimide) with respect to NMP (N-methyl-2-pyrrolidone) (density ρ: 1052 kg / m ³ ), viscosity μ: 0.26 Pa · s ). As shown in FIG. 7, the nozzle shape was a nozzle whose front shape was an oval shape. Table 1 shows the dimensions of each part. As a comparative example, calculation was performed for two types of nozzles having a perfect circle shape and different diameters.

(Calculation result)
8 and 9 show the simulation results of the velocity distribution of the nozzles according to the first to third embodiments. In FIG. 9, the vertical axis indicates the flow rate arrival rate (%) when the maximum flow rate is 100, and the horizontal axis indicates the position in the X-axis or Y-axis direction. 10 and 11 show the simulation results of Comparative Examples 1 and 2. FIG. From this figure, it was confirmed that the nozzles according to Examples 1 to 3 have different flow velocity distributions on the X axis and the Y axis, and there is a region where the velocity is constant on the X axis. On the other hand, the nozzles according to Comparative Examples 1 and 2 have the same flow velocity distribution on the X axis and the Y axis.

  FIG. 12 shows the velocity vector of the nozzle according to Example 1 from the nozzle inlet to 0.5 mm. FIG. 13 shows velocity vectors of Comparative Examples 1 and 2.

  14 and 15 show the simulation results of the shear rate distribution of the nozzles according to Examples 1 to 3. FIG. In FIG. 15, the vertical axis represents the shear rate (1 / s), and the horizontal axis represents the position in the X-axis or Y-axis direction. 16 and 17 are simulation results of Comparative Examples 1 and 2. FIG. From this figure, it was confirmed that the nozzles according to Examples 1 to 3 have different shear rate distribution states on the X-axis and the Y-axis, and there is a region where the shear rate is constant on the X-axis. On the other hand, the nozzles according to Comparative Examples 1 and 2 have the same shear rate distribution on the X axis and the Y axis.

Table 2 shows the result of calculating the area ratio in the high shear rate region. FIG. 18 shows a high shear region when the shear rate is 1 × 10 ⁷ (1 / s). From this figure, the nozzles according to Examples 1 to 3 have a large area of a high shear rate region (black part in the figure) and a wide area with a low shear rate (white part in the figure). Therefore, it can be said that the solid matter can be dispersed more finely while preventing the solid matter contained in the treatment liquid from clogging the flow path as the whole nozzle.

  On the other hand, in Comparative Example 1, since the nozzle inner diameter is large, the area of the high shear rate region is small and is occupied by the region where the shear rate is almost small. Therefore, it can be said that it is difficult to efficiently disperse the solid matter. In Comparative Example 2, although the area of the high shear region is large, the region where the shear rate is low is narrow, so it can be said that the solid matter is easily clogged in the flow path.

DESCRIPTION OF SYMBOLS 10 Dispersing device 16A-16D Nozzle part 24, 30, 32, 34 Nozzle 36 1st axis | shaft side inner surface 38 2nd axis | shaft side inner surface D Distance between 1st axis | shaft side inner surfaces F Traveling direction H Distance X between 2nd axis | shaft side inner surfaces 1st axis Y 2nd axis

Claims (5)

In a dispersing apparatus that disperses solid matter contained in the processing liquid by passing the pressurized processing liquid through the nozzle,
The nozzle is
The cylindrical member has an opening parallel to the traveling direction of the treatment liquid,
The distance D between the inner surfaces on the first axis side orthogonal to the traveling direction is formed longer than the distance H between the inner surfaces on the second axis side orthogonal to the traveling direction and the first axis, The distance D is 50 to 300 μm, the ratio D / H between the distance D and the distance H is 1.5 to 16,
Prior Symbol first axis, a total flow rate substantially constant the nozzle, before Symbol second axis, the dispersion apparatus center of the nozzle is characterized more flow velocity is high. In a dispersing apparatus that disperses solid matter contained in the processing liquid by passing the pressurized processing liquid through the nozzle,
The nozzle is
Side of the inner surface of the first axis orthogonal to the traveling direction of the treatment liquid, from the side of the inner surface of the second axis orthogonal to the traveling direction and the first axis, which is maintained at a high temperature,
Wherein the first axis, a total flow rate substantially constant the nozzle, it said the second axis, the central feature and to that distributed system more flow speed is fast <br/> that of the nozzle. In a dispersing apparatus that disperses solid matter contained in the processing liquid by passing the pressurized processing liquid through the nozzle,
The nozzle is
The inner surface side of the first axis orthogonal to the traveling direction of the treatment liquid, from the side of the inner surface of the second axis orthogonal to the traveling direction and the first axis, roughness rather small,
Wherein the first axis, a total flow rate substantially constant the nozzle, it said the second axis, the central feature and to that distributed system more flow speed is fast <br/> that of the nozzle. In a dispersing apparatus that disperses solid matter contained in the processing liquid by passing the pressurized processing liquid through the nozzle,
The nozzle is
The inner surface side of the first axis orthogonal to the traveling direction of the treatment liquid, possess no affinity to the treatment liquid,
Wherein the first axis, a total flow rate substantially constant the nozzle, it said the second axis, the central feature and to that distributed system more flow speed is fast <br/> that of the nozzle. In a dispersion method comprising a step of passing a pressurized treatment liquid through a nozzle, and dispersing solids contained in the treatment liquid,
A cylindrical member is opened parallel to the traveling direction of the processing liquid, and a distance D between the inner surfaces on the first axis side perpendicular to the traveling direction is perpendicular to the traveling direction and the first axis. The distance D is longer than the distance H between the inner surfaces on the second axis side, the distance D is 50 to 300 μm, and the ratio D / H between the distance D and the distance H is 1.5 to 16. In the nozzle,
Prior Symbol first axis, total flow rate of the nozzle is substantially constant, before Symbol second center of the nozzle in an axial more flow rate fast Kunar so, and wherein the passing the processing solution Distribution method.

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