JP2009097938A - Purification method of charged particle dispersed undiluted solution, and microchannel device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a purification method of charged particle dispsersed undiluted solution capable of removing metal ions from the particle scattering undiluted solution containing charged particles and the metal ions. <P>SOLUTION: This purification method includes a process described as follows: the particle dispersed undiluted solution containing the charged particles and the metal ions is sent into a microchannel 1 so as to form a laminar flow; the first cleaning liquid 1 is sent into a microchannel 2 so as to form a laminar flow; the second cleaning liquid 2 is sent into a microchannel 3 so as to form a laminar flow; an electric field is applied in the direction crossing the flow on a microchannel joining part where three laminar flows join together, and thereby the charged particles are moved from the microchannel 1 side to the microchannel 3 side, and the metal ions are moved from the microchannel 1 side to the microchannel 2 side; and the charged particles are recovered from a branched microchannel 3 and the metal ions are discharged into a branched microchannel 1 or 2 or a branched microchannel 12, on the downstream side of the microchannel joining part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for purifying a charged particle dispersion stock solution and a microchannel device.

  Patent Document 1 discloses a method for concentrating a fine particle dispersion and a concentrating device used for this purpose. In this concentration method, the fine particle dispersion is fed to a liquid feeding section having a minute width, and the fine particles flowing in a laminar flow are applied by applying an electric field in the direction intersecting the flow direction, which is located downstream of the liquid feeding section. The particles are moved to one direction, and the moved fine particles are concentrated and collected.

JP 2006-205092 A

  The problem to be solved by the present invention is to provide a method for purifying a charged particle dispersion stock solution capable of removing coexisting metal ions from a particle dispersion stock solution containing charged particles and metal ions, and a microchannel device used therefor It is to be.

  The method for purifying a charged particle dispersion stock solution of the present invention comprises three micro channels 1 to 3 for feeding three types of liquids 1 to 3 as a laminar flow, and these micro channels 1 to 3 merge at one place. And the three branch microchannels 1 to 3 provided corresponding to the microchannels 1 to 3 on the downstream side of the microchannel junction, and the microchannel junction Preparing a microchannel device having a pair of electrodes on the inner wall of the microchannel merging portion for providing an electric field in a direction intersecting with three kinds of liquid flows in the section, particles containing charged particles and metal ions The dispersion stock solution is sent to the microchannel 1 so as to form a laminar flow, the first cleaning solution 1 is sent to the microchannel 2 so as to form a laminar flow, and the second cleaning solution 2 causes the laminar flow to flow. The liquid is fed to the microchannel 3 so as to form, and the direction intersecting the flow at the microchannel merging portion where these three laminar flows merge By applying an electric field, the charged particles are moved from the microchannel 1 side to the microchannel 3 side, and metal ions are retained on the microchannel 1 side or the microchannel 2 side, and downstream of the microchannel merging portion. And a step of collecting charged particles from the branched microchannel 3 and discharging metal ions to the branched microchannel 1 or 2.

  The microchannel device of the present invention is a microchannel device for removing metal ions from a particle dispersion stock solution containing charged particles and metal ions, and sends three types of liquids 1 to 3 as a laminar flow. Three microchannels 1 to 3 for liquefying, a microchannel merging portion where these merging microchannels merge at one place, and microchannels 1 to 3 downstream of the microchannel merging portion A pair of electrodes having three branching microchannels 1 to 3 provided in correspondence with each other, and a pair of electrodes for applying an electric field in a direction intersecting the flow of three kinds of liquids at the junction. It is characterized by having on the inner wall.

According to the present invention, charged particles can be purified by efficiently removing metal ions from a particle dispersion stock solution containing charged particles and coexisting metal ions.
The present invention can be effectively applied to charged particles having a particle diameter of about 1 μm, preferably 0.1 to 10 μm.

  The method for purifying a charged particle-dispersed stock solution according to this embodiment includes three microchannels 1 to 3 for feeding three types of liquids 1 to 3 as a laminar flow, and these microchannels 1 to 3 are provided at one location. The microchannel merging portion to be merged, and two branched microchannels 12 and 3 or three branched microchannels provided corresponding to the microchannels 1 to 3 on the downstream side of the microchannel merging portion, respectively. 1 to 3 and a microchannel device having a pair of electrodes on the inner wall of the microchannel merging portion for applying an electric field in a direction intersecting with three kinds of liquid flows in the microchannel merging portion Step, the liquid particle dispersion containing charged particles and metal ions is sent to the microchannel 1 so as to form a laminar flow, and the liquid is fed to the microchannel 2 so that the first cleaning liquid 1 forms a laminar flow. Then, the second cleaning liquid 2 is sent to the micro flow path 3 so as to form a laminar flow, and these three laminar flows are merged. By applying an electric field in a direction intersecting the flow at the junction, the charged particles are moved from the microchannel 1 side to the microchannel 3 side, and metal ions are retained on the microchannel 1 side or the microchannel 2 side. And collecting the charged particles from the branch microchannel 3 and discharging the metal ions to the branch microchannel 12 or the branch microchannel 1 or 2 on the downstream side of the microchannel junction.

The microchannel device of the present embodiment is a microchannel device for removing metal ions from a particle dispersion stock solution containing charged particles and metal ions, and three types of liquids 1 to 3 are used as laminar flows. Three microchannels 1 to 3 for feeding liquid, a microchannel merging portion where these merging microchannels merge at one place, and microchannels 1 to 3 downstream of the microchannel merging portion Each of the two branch microchannels 12 and 3 or three of the branch microchannels 1 to 3 are provided corresponding to each of the two, and an electric field is applied in the direction intersecting the three liquid flows at the junction. A pair of electrodes is provided on the inner wall of the microchannel junction.
Hereinafter, the purification method of the present embodiment and the microchannel device used for this purpose will be described with reference to the drawings as appropriate.

FIG. 1 is a conceptual diagram showing an embodiment of the microchannel device of the present embodiment.
The microchannel device shown in FIG. 1 has three microchannels 1 to 3 (I-1, I-2, and 1) for feeding three types of liquid 1, liquid 2 and liquid 3 as a laminar flow in the upper part thereof. I-3). This microchannel device has an inlet (not shown) for introducing a liquid to be fed into these three microchannels 1 to 3 (I-1, I-2 and I-3). Yes. The three microchannels 1 to 3 (I-1, I-2, and I-3) form a microchannel merging portion 123 that merges at one location downstream. In the microchannel merging section 123, the above three liquids merge and are sent as a laminar flow G-1, a laminar flow G-2, and a laminar flow G-3.

The liquids 1 to 3 fed to the three microchannels 1 to 3 (I-1, I-2, and I-3) are three laminar flows G-1 to G-3 that are completely in contact with each other. For this reason, it is preferable that the cross sections of the three microchannels 1 to 3 (I-1, I-2, and I-3) before joining are rectangular. The length of the long side of the rectangle can be selected as appropriate, but is preferably about several to about several thousand μm (meaning “several μm to several thousand μm or less”), and more preferably 50 to 500 μm. . Further, the microchannel I-2 located in the middle is in contact with the microchannels I-1 and I-3 on both sides to form the microchannel merging portion 123. The flow path length of the merge portion can be selected as appropriate, but is preferably about ten to several hundred mm, and more preferably 50 to 200 mm.
Corresponding to the three microchannels 1 to 3 (I-1, I-2, and I-3), three branch microchannels 1 to 3 are provided on the downstream side of the end of the junction of the microchannel junction 123. 3 (O-1, O-2 and O-3) are provided. It is preferable that the cross-sections of these branched microchannels 1 to 3 have substantially the same shape and area as the cross-section of the microchannels 1 to 3.
In addition, as shown in FIG. 3, it can also be set as the one branch microchannel O-12 which united the branch microchannel O-1 and O-2.
Moreover, although the flow path height orthogonal to the flow direction of the micro flow path and the height of the micro flow path merging portion can be selected as appropriate, it is preferably about 10 to about 1000 μm, and preferably 50 to 100 μm. Is more preferable.

  In FIG. 1, a pair of electrodes is provided on the inner surfaces of the flow channel walls on both sides in the direction intersecting with the three laminar flows G-1 to G-3 in the micro flow channel confluence portion 123. When the cross section of the microchannel merging portion is rectangular as a whole, the electrodes are preferably a pair of opposed parallel plate electrodes. The direction of the electric field formed by the pair of electrodes is a direction that intersects the flow direction of the laminar flow in which the three kinds of liquids 1 to 3 that flow adjacent to each other in the microchannel merging portion 123, and in FIG. They are almost orthogonal. The electrode is preferably manufactured using a material that is not easily corroded, such as platinum. The electrode length is preferably 50% or more of the combined flow path length, more preferably 80 to 95%.

  The microchannel device of the present embodiment can use materials generally used for microchannel fabrication such as glass, silicone, ceramics, PMMA, etc., and a known microchannel device manufacturing method can be used. It can be adopted and manufactured.

FIG. 2 is a conceptual diagram showing an embodiment of the method for purifying the particle dispersion stock solution according to the present embodiment.
The microchannel in the present embodiment refers to a channel having a width of about several to about several thousand μm. The width of the microchannel is preferably 50 to 1,000 μm, and more preferably 50 to 500 μm. In the purification method of this embodiment, the Reynolds number of the liquid flowing through the three microchannels is 2,300 or less, and the flow is not turbulent but laminar. The width and the number of lay nozzles in the branch microchannel are the same as those of the microchannel.
Here, the Reynolds number (Re) is expressed by the following formula, and when it is 2,300 or less, the laminar flow is dominant.
・ Re = uL / ν (u: flow velocity, L: representative length, ν: kinematic viscosity coefficient)
In the laminar-dominated world as described above, the viscosity term contributes more to the inertia term, so basically the flow does not cause the medium to move in the direction intersecting the flow direction. . Therefore, diffusion of charged particles due to turbulent flow is prevented.
In the purification method of the present embodiment, charged particles are electrophoresed in a direction crossing the flow direction by the action of an electric field.

In the method for purifying the particle dispersion stock solution of the present embodiment, the particle dispersion stock solution containing charged particles and metal ions, the cleaning solution 1 and the cleaning solution 2 are introduced from the corresponding inlets provided in the microchannel device. Each is sent to the microchannels 1 to 3 (I-1, I-2 and I-3). A known means such as a quantitative liquid feeding pump can be used for liquid feeding. Three laminar flows G-1, G-2, and G-3 formed by three liquids are brought into contact with each other and fed in the microchannel merging portion 123 where these three microchannels merge. An electric field is applied in a direction intersecting with the flow direction of these three liquids. The direction of the electric field is such that the charged particles in the particle dispersion stock solution containing charged particles are sent from the micro flow channel I-3 from the laminar flow G-1 side where the charged particles are sent from the micro flow channel I-1. It applies so that it may move to the liquid laminar flow G-3 side. For negatively charged particles, the laminar flow G-1 side is the negative (-) electrode and the laminar flow G-3 side is the positive (+) electrode, so that Charged particles can be moved from the laminar flow G-1 side to the laminar flow G-3 side by electrophoresis.
The charged particles move from the laminar flow G-1 to the laminar flow of the cleaning liquid 1 and further to the laminar flow of the cleaning liquid 2 in the microchannel merging portion to which an electric field is applied. Accordingly, the charged particles can be recovered from the branched microchannel O-3 downstream of the microchannel junction.

On the other hand, the metal ions existing outside the charged particles in the particle dispersion stock solution remain in the laminar flow G-1 by the action of the negative electrode provided on the laminar flow G-1 side at the microchannel merging portion. Further, when the metal ions present inside the charged particles (including the surface) move to the laminar flow G-2 together with the charged particles, the metal ions are washed by the action of the cleaning agent in the cleaning liquid 1 and laminar flow G-2. Can be retained within.
In this way, on the downstream side of the junction, the charged particles can be recovered from the branched microchannel O-3 together with the cleaning liquid 2, and the metal ions as impurities are branched microchannel O-1 or O-2. Or it can be discharged from O-12. As a result, the charged particles in the charged particle dispersion stock solution can be purified.

When the charged particles are negatively charged particles, as a preferred embodiment, the cleaning liquid 1 is an aqueous solution containing an aqueous solution of an acid capable of forming a salt with metal ions in the particle dispersion stock solution. The case where it is pure water can be mentioned.
The acid that can form a salt with a metal ion used as the cleaning liquid 1 may be a mineral acid or an organic acid, and is preferably an acid that forms a soluble or hardly soluble neutral salt with the metal ion.
In this case, when a particle-dispersed stock solution containing metal ions is fed into the microchannel I-1 inside the negatively charged particles (including the surface), electricity is applied from the laminar flow G-1 side at the microchannel junction. The metal ions that have moved along with the negatively charged particles in the laminar flow G-2 of the cleaning liquid 1 by electrophoresis form an acid and a salt contained in the cleaning liquid 1. When this salt is neutral, the metal salt is no longer affected by the electric field and stays in the laminar flow G-2, and can be discharged from the branch microchannel O-2.
The negatively charged particles are further washed from the laminar flow G-2 with pure water of the laminar flow G-3 and recovered from the branched microchannel O-3.

The reaction between the metal ions contained in the particle dispersion stock solution and its acid in the microchannel I-1 will be described.
The metal ions contained in the particle dispersion undiluted solution include metal ions that are unintentionally mixed as so-called contaminants in addition to the metal ions used as the treating agent in the charged particle production process. In the case of a toner manufactured by an emulsion polymerization aggregation method, a metal ion includes a polyvalent metal salt added as an aggregating agent.
As the first cleaning liquid, an aqueous solution of an acid capable of forming a hardly soluble salt with the metal ions in the dispersion stock solution can be used. Examples of such acids include mineral acids such as dilute sulfuric acid. When water-soluble calcium ions (Ca ²⁺ ) are present in the dispersion stock solution, Ca ²⁺ forms dihydrate of calcium sulfate (CaSO ₄ .2H ₂ O) at 66 ° C. or less with dilute sulfuric acid.

Further, as an acid capable of forming a salt with a metal ion, acetic acid, oxalic acid, succinic acid or an organic acid such as an alkali metal salt or ammonium salt thereof (Li ⁺ , Na ⁺ , K ⁺ , NH ₄ ⁺ ) or an acid thereof A salt can also be preferably used. In an aqueous solution of ammonium oxalate, water-soluble calcium ions (Ca ²⁺ ) form a hardly soluble salt of calcium oxalate ^monohydrate .
As the cleaning liquid 1, an aqueous solution of a ligand that forms a water-soluble metal complex with a transition metal ion such as EDTA (ethylenediaminetetraacetic acid) or a normal metal ion can also be used.

The liquid feed amount of liquids 1 to 3 is preferably 0.001 to 100 ml / hr, and more preferably 0.01 to 50 ml / hr. Accordingly, the discharge amount is also within this range.
In order to increase the amount of purification, numbering up can be performed to increase the number of microchannel devices.

  The volume average particle diameter of the charged particles to be purified in this embodiment is preferably 0.1 μm to 500 μm, and more preferably 0.1 to 10 μm. When the average particle size is within the above range, high purification efficiency can be obtained.

In the present embodiment, the volume average particle diameter of the particles is a value measured using a Coulter Counter TA-II type (manufactured by Coulter Inc.) except for the following particle diameter (5 μm or less). In this case, measurement is performed using an optimum aperture according to the particle size level of the particles. When the particle diameter is 5 μm or less, measurement is performed using a laser diffraction / scattering particle size distribution measuring device (LA-920, manufactured by Horiba, Ltd.).
The specific gravity of the particles is measured by a gas phase substitution method (pycnometer method) using an ultra pycnometer 1000 manufactured by Yuasa Ionics.
The specific gravity of the medium liquid is measured using a specific gravity measurement kit AD-1653 manufactured by A & D.

The purification method of the present embodiment can be applied to various charged particles, and includes an electrostatic charge image developing toner. As the toner for developing an electrostatic image, the purification method of the present embodiment can be more preferably applied to the toner produced by the emulsion polymerization aggregation method than the kneading pulverization method or the suspension polymerization method.
In the emulsion polymerization aggregation method, a resin particle dispersion in which binder resin particles having a particle diameter of 1 μm or less obtained by emulsion polymerization are dispersed, a colorant dispersion in which a colorant is dispersed, and a release agent as necessary. The dispersed release agent dispersion is aggregated into a toner particle size. After this aggregation step, the aggregated particles are heated to a temperature equal to or higher than the glass transition temperature of the binder resin to fuse the aggregates to form toner particles. In the aggregating step, an ionic surfactant or a polyvalent metal salt (such as aluminum sulfate) is used in order to perform heteroaggregation to form aggregated particles having a toner particle diameter.
An electrostatic latent image developing toner particle dispersion prepared by an emulsion polymerization aggregation method has Al ³⁺ , Mg ²⁺ , Ca ²⁺ , Cu ²⁺ , Fe ³⁺ , Na ^{+ and the} like outside or inside the toner particles. Containing metal ions.

  Although the shape of the particle | grains used for this embodiment is not specifically limited, A spherical shape or a substantially spherical particle | grain is preferable. The ratio of the major axis length to the minor axis length (major axis length / minor axis length) of these particles is preferably in the range of 1 to 20, and more preferably in the range of 1 to 2.

The charged particles in the particle dispersion undiluted solution used in the present embodiment have a positive or negative charge in the medium liquid. For example, in an aqueous medium, when an acidic group such as —COOH or —SO ₃ H is present on the particle surface, it shows a negative charge, and when a basic group such as —NH ₂ or —NH ₃ ⁺ is present. Has a positive charge.

As an example of the particle | grains which show a negative charge in the said medium liquid, the particle | grains containing the addition polymerizable binder which has said acidic group in a side chain can be illustrated. These binders can be produced by copolymerizing an ethylenically unsaturated compound having an acidic group and an ethylenically unsaturated compound having no acidic group.
The ethylenically unsaturated compound having an acidic group is preferably an ethylenically unsaturated compound having a sulfonic acid group, a carboxyl group, a phosphoric acid group or a carboxylic acid anhydride group, such as 2-acrylamido-2-methylpropanesulfonic acid, methacrylic acid. Examples include acid, acrylic acid and maleic anhydride.
Further, as the ethylenically unsaturated compound having no acidic group for constituting the copolymer, styrene, o-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p- Styrenes such as tert-butylstyrene, pn-dodecylstyrene, p-chlorostyrene, p-phenylstyrene; olefins such as ethylene, propylene, isobutylene; vinyl chloride; vinyl acetate, vinyl butyrate, vinyl benzoate, etc. Vinyl esters; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, acrylic acid Phenyl, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate , (Meth) acrylic acid esters, such as stearyl methacrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, polypropylene glycol monomethacrylate, polyethylene glycol monomethacrylate; acrylonitrile Ethylenically unsaturated nitriles such as methacrylonitrile; acrylamides such as acrylamide; vinyl vinyl ketone, vinyl hexyl ketone, methyl Examples thereof include vinyl ketones such as ruisopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone. Moreover, you may use these 1 type, or 2 or more types.

On the other hand, examples of the particles exhibiting positive charge in the medium liquid include particles containing an addition polymerizable binder having a basic group in the side chain. These binders are preferably produced by copolymerizing an ethylenically unsaturated compound having a basic group and an ethylenically unsaturated compound having no basic group.
The ethylenically unsaturated compound having a basic group is preferably an ethylenically unsaturated compound having a secondary, tertiary or quaternary amino group, and more preferably an ethylenically unsaturated compound having a tertiary or quaternary amino group. . The tertiary amino group can also be quaternized after making the polymer.
Examples of the ethylenically unsaturated compound having a tertiary or quaternary amino group include dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, Nn-butoxyacrylamide, diacetone acrylamide, acrylamide, N- Examples include vinyl carbazole, vinyl pyridine, 2-vinyl imidazole, 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride, 2-hydroxy-3-acryloxypropyltrimethylammonium chloride, or quaternized nitrogen thereof. .
When an ethylenically unsaturated compound having no basic group is copolymerized, one or more of the above-described ethylenically unsaturated compounds having no acidic group can be used as a copolymerization monomer.

Further, the charged particles used in the present embodiment may be inorganic particles. As such inorganic particles, metal oxides such as SiO ₂ and TiO ₂ exhibit negative polarity. Examples of positive polarity include aluminum oxide. Further, it is known that those treated with a silane treating agent exhibit positive and negative polarities depending on the type and ratio of the terminal groups of the treating agent. For example, by treating SiO ₂ with a silane treatment agent containing an amino group or the like, positive polarity is exhibited.

On the other hand, in the present embodiment, any medium liquid can be used as the liquid, but the electric conductivity of the medium liquid is preferably 0 to 50 μs / cm, more preferably 0 to 20 μs / cm, and still more preferably. Is 0-10 μs / cm.
As the medium liquid preferably used in the present embodiment, for example, water, alcohol or the like can be used, and an aqueous medium mainly containing water is preferable, and water is particularly preferable.

  In the present embodiment, a preferable combination of particles and a medium liquid includes a polystyrene acrylate copolymer having a carboxyl group on its surface or a polyester resin particle and a polyester resin particle and an aqueous medium, a polystyrene acrylate copolymer having an amino group or a quaternary ammonium group. Or the aqueous dispersion of the polyester-type resin particle is mentioned, Among these, the aqueous dispersion stock solution of the charged particle which contains the polystyrene acrylic resin which has a carboxyl group on the surface as binder resin is more preferable.

  The concentration of the particles in the particle-dispersed stock solution used in the present embodiment is preferably 0.1 to 40% by volume, and more preferably 1 to 25% by volume.

  Hereinafter, the purification method of the present embodiment will be described more specifically by way of examples. However, the present embodiment is not limited to these examples.

  In Example 1, a microchannel device as schematically shown in FIG. 1 was used. This microchannel device is a device made of glass, and a microchannel device in which three microchannels merge to form a microchannel merging portion and further divided into three branch microchannels was used. W1 = W2 = W3 = 100 μm, D (depth) = 100 μm, merge portion length L2 = 100 mm, and electrode length L1 = 90 mm.

Using this microchannel device, for developing an electrostatic image having an average particle diameter of about 2 μm, which is produced by the emulsion polymerization aggregation method on the microchannel I-1 and is negatively charged by the copolymerized acrylic acid unit. Toner particles were dispersed in water, and a particle dispersion stock solution containing an impurity electrolyte (containing Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Cu ²⁺ , and Na ⁺ as metal ions) was introduced. A dilute oxalic acid aqueous solution was introduced into the microchannel I-2, and pure water was introduced into the channel I-3. The flow rate was 6 ml / hr for all of the microchannels I-1, I-2 and I-3.
The interelectrode voltage was 3 V and the electric field was 100 V / cm.
The purified electrophotographic toner particles with reduced metal ions could be recovered from the branched microchannel O-3.
The electrostatic toner thus collected has improved charging characteristics in the electrophotographic process, and stable image quality can be obtained in various environments where the electrophotographic apparatus is installed. In addition, the life of the photoreceptor on which the toner image (latent image) is formed is improved.

It is a conceptual diagram which shows one embodiment of the microchannel apparatus of this embodiment. It is a conceptual diagram which shows typically one implementation of the purification method of this embodiment. It is a conceptual diagram which shows another embodiment of the microchannel apparatus of this embodiment.

Explanation of symbols

I-1: Microchannel 1
I-2: Microchannel 2
I-3: Microchannel 3
123: Micro flow path confluence G-1: Laminar flow 1
G-2: Laminar flow 2
G-3: Laminar flow 3
O-1: Branched microchannel 1
O-2: Branched microchannel 2
O-12: Branched microchannel 12
O-3: Branched microchannel 3
+: Positive electrode-: Negative electrode L1: Length of electrode L2: Length of micro-channel confluence

Claims (3)

Three micro-channels 1 to 3 for feeding three types of liquids 1 to 3 as a laminar flow, a micro-channel merging section where these micro-channels 1 to 3 merge at one place, and the micro-stream In the two branch microchannels 12 and 3 or three branch microchannels 1 to 3 provided corresponding to the microchannels 1 to 3 on the downstream side of the channel junction, and in the microchannel junction Preparing a microchannel device having a pair of electrodes for applying an electric field in a direction intersecting with three types of liquid flows on the inner wall of the microchannel merging portion;
The liquid particle dispersion containing charged particles and metal ions is sent to the microchannel 1 so as to form a laminar flow, and the first cleaning solution 1 is sent to the microchannel 2 so as to form a laminar flow. The second cleaning liquid 2 is sent to the microchannel 3 so as to form a laminar flow,
By applying an electric field in the direction crossing the flow at the microchannel merging portion where these three laminar flows merge, the charged particles are moved from the microchannel 1 side to the microchannel 3 side and metal ions are moved to the microchannel 1. Side or microchannel 2 side,
A step of collecting charged particles from the branch microchannel 3 and discharging metal ions to the branch microchannel 12 or the branch microchannel 1 or 2 on the downstream side of the microchannel junction. A method for purifying a charged particle dispersion stock solution.   The charged particles are negatively charged, the particle dispersion undiluted solution contains metal ions inside and / or outside of the charged particles, the cleaning solution 1 is an aqueous solution containing an acid capable of forming a salt with the metal ions, and the cleaning solution 2 The method for purifying a charged particle-dispersed stock solution according to claim 1, wherein is pure water. A microchannel device for removing metal ions from a particle dispersion stock solution containing charged particles and metal ions,
Three micro-channels 1 to 3 for sending three types of liquids 1 to 3 as a laminar flow, a micro-channel merging section where these merging micro-channels merge at one place, and the micro-channel merging 2 branch microchannels 12 and 3 provided corresponding to the microchannels 1 to 3 on the downstream side of the section, or three branch microchannels 1 to 3, respectively. A microchannel device comprising a pair of electrodes for applying an electric field in a direction crossing the liquid flow of the liquid crystal on the inner wall of the microchannel merging portion.

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