JP2009227841A - Method and apparatus for producing fine particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conduct filtration and redispersion in the post-process with high precision and in a normal manner because the formation of agglomerates can be performed uniformly. <P>SOLUTION: An apparatus is composed of a unit of the combination of a means for forming a fine particle by bringing a solution L1 in which an organic pigment is dissolved in a good solvent and a poor solvent L2 which is compatible with the good solvent and does not solve the organic pigment into contact with each other, to precipitate an organic pigment fine particle, and a means for forming an agglomerate by agglomerating the resultant organic pigment fine particle with an agglomeration agent to form an agglomerate. The apparatus is provided with a reaction channel 30 for mixing the solution L1 and the poor solvent L2 and carrying out the precipitation and agglomeration of the organic pigment fine particle, a plurality of introducing channels 32, 34 which communicate with a mixing part 36 of the reaction channel 30 for introducing the solution L1 and the poor solvent L2 so as to merge into the mixed part 36 as a confluent point to form a multiple laminar flow L and an addition means 22 for adding an agglomeration agent to the poor solvent L2 before the poor solvent reaches the mixed part 36 of the reaction channel 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for producing fine particles, and more particularly to a technique for producing fine particles by once forming fine particles to aggregate to remove unnecessary substances and then redispersing them.

  As one method for producing inorganic or organic fine particles, there is a build-up method in which fine particles are precipitated by contacting a solution in which the fine particle forming material is dissolved in a solvent with a poor solvent in which the fine particle forming material is difficult to dissolve. .

  As an example of the fine particles produced by the build-up method, there are organic pigment fine particles contained in the ink of the ink jet apparatus. In recent years, with the progress of digitization, output expressions such as images have been diversified, and the stability of color images over time has been demanded. In response to such movements, a transparent color image forming method having good weather resistance and heat resistance is demanded, and organic pigments are attracting attention from the viewpoint of weather resistance and heat resistance. In particular, in recent years, it has been demanded to use organic pigment fine particles of 100 nm or less, preferably 40 nm or less.

As a method for producing organic pigment fine particles by such a build-up method, for example, there is Patent Document 1 below. In Patent Document 1, as shown in FIGS. 5A to 5D, using a microreactor 1, a solution L1 in which a fine particle forming material is dissolved in a good solvent, and a fine particle forming material compatible with the good solvent. A poor solvent L2 that does not dissolve the solvent is brought into contact with the reaction channel 3 to prepare a dispersion liquid in which the organic pigment fine particles A are deposited. Thereafter, an acid B (aggregating agent) is added from the nozzle 5 into the tank 4 in which the dispersion liquid is stored, thereby forming an aggregate B of the organic pigment fine particles A. Thereby, it is easy to remove unnecessary substances (excess flocculant C and dispersant D) in the dispersion by filtration through the filter 6, and then the aggregate B is redispersed (for example, pH adjustment) to thereby remove unnecessary substances. It is described that the organic pigment fine particles A can be produced.
JP 2004-43776 A

  However, since Patent Document 1 is a system in which a dispersion liquid containing organic pigment fine particles A formed in the microreactor 1 is stored in a tank 4 and an acid (flocculating agent) is added to the tank 4, there is the following problem.

  That is, in order to make the inside of the tank 4 have a constant acid concentration, an acid having a concentration several times higher than the necessary acid concentration must be added from the nozzle 5, and the acid concentration in the tank 4 depends on the addition position. A large concentration distribution occurs at a position away from the addition. As a result, the agglomeration reaction becomes uneven depending on the position in the tank 4, and there is a problem that high accuracy and normal filtration and redispersion cannot be performed when the aggregate B is filtered and redispersed later. is there. As a result, nanometer (nm) size organic pigment fine particles having excellent monodispersibility cannot be produced.

  In addition, two devices, the microreactor 1 that performs the fine particle forming process and the tank 4 that performs the aggregate forming process, are required, leading to an increase in cost.

  These problems included in Patent Document 1 are not limited to the case where the organic pigment fine particles are produced by the build-up method, but also apply when other organic or inorganic fine particles are produced by the build-up method.

  The present invention has been made in view of such circumstances, and since aggregate formation can be performed uniformly, filtration and redispersion in post-processes can be performed with high accuracy and normality, and fine particle formation and aggregation can be performed. It is an object of the present invention to provide a fine particle production method and apparatus capable of simplifying the apparatus for producing fine particles since the aggregate formation can be performed at once.

  According to a first aspect of the present invention, in order to achieve the above object, a solution obtained by dissolving a fine particle forming material in a good solvent is brought into contact with a poor solvent which is compatible with the good solvent and does not dissolve the fine particle forming material. A fine particle forming step for precipitating particles, an agglomerate forming step for aggregating the formed fine particles with an aggregating agent, a filtration step for filtering the aggregate, and a re-dispersion of the aggregate after filtration into fine particles A redispersion step, wherein the fine particles formed while forming the fine particles by continuously circulating the solution and the poor solvent through the reaction flow channel are formed in the reaction flow channel. Provided is a method for producing fine particles, wherein the fine particle forming step and the aggregate forming step are performed in the reaction channel at a time by contacting the flocculant.

  According to the first aspect, the fine particles formed by bringing the solution in which the fine particle forming material is dissolved in the reaction channel into contact with the poor solvent are brought into contact with the flocculant in the reaction channel. Thereby, since the aggregate can be formed in the reaction channel where the concentration distribution of the flocculant hardly occurs, a uniform aggregation reaction can be performed. As a result, it is possible to form the normal intended aggregate having a uniform size and cohesive strength with high accuracy. Thereby, since filtration and redispersion in a post-process can be performed with high accuracy, it is possible to manufacture nanometer (nm) size fine particles free from unnecessary substances and excellent in monodispersity.

  A second aspect of the present invention is characterized in that in the first aspect, the poor solvent contains a flocculant in advance, and the poor solvent containing the flocculant is introduced into the reaction channel.

  According to claim 2, it is possible to add a flocculant to the reaction flow path, but if the poor solvent contains the flocculant in advance and the poor solvent containing the flocculant is introduced into the reaction flow path, The flocculant distribution in the reaction channel can be further eliminated.

  A third aspect of the present invention is the method according to the first or second aspect, wherein the produced fine particles are organic pigment fine particles.

  This is because the formation of organic pigment fine particles and the formation of aggregates have many unsolved problems as described above and can be solved by carrying out the present invention.

  According to a fourth aspect of the present invention, in order to achieve the above-mentioned object, a solution obtained by dissolving a fine particle forming material in a good solvent is brought into contact with a poor solvent which is compatible with the good solvent and does not dissolve the fine particle forming material. Fine particle forming means for precipitating particles, an aggregate forming means for aggregating the formed fine particles with an aggregating agent, a filtering means for filtering the aggregate, and a re-dispersion of the aggregate after filtration into fine particles And a redispersion means that comprises the fine particle forming means and the aggregate forming means as one device, wherein the device comprises the solution and the poor solvent. A reaction flow path for mixing and precipitating and agglomerating fine particles, and communicating with the mixing section of the reaction flow path, introducing the dissolved solution and the poor solvent so as to merge at the mixing section. A plurality of introduction flow paths forming a flow; Providing an additive means for adding a flocculant to the poor solvent to reach the mixing section of the flow path, the particle manufacturing apparatus characterized by comprising a.

  According to a fourth aspect of the present invention, the present invention is configured as an apparatus. The apparatus includes a reaction flow path, a plurality of introduction flow paths that join a dissolving solution and a poor solvent at a mixing portion of the reaction flow path, and a poor solvent. With the addition means for adding an aggregating agent to the two, two means of fine particle formation and aggregate formation can be configured as one apparatus. As a result, aggregate formation can be performed uniformly, so that filtration and redispersion in subsequent steps can be performed with high accuracy, and fine particle formation and aggregate formation can be performed at a time. Equipment for manufacturing can be simplified.

  According to a fifth aspect of the present invention, in the fourth aspect, at least three or more introduction flow paths are provided on the same surface, and the solution introduction flow paths and the poor solvent introduction flow paths are alternately arranged. Features.

  According to the fifth aspect of the present invention, at least three or more introduction flow paths are provided on the same surface so that the solution introduction flow path and the poor solvent introduction flow path are alternately arranged. In the mixing section, the solution and the poor solvent are mutually contracted to form a tapered flow. As a result, a sandwich-type multilayer flow in which thin layers of the solution and thin layers of the poor solvent are alternately stacked is formed in the mixing portion of the reaction channel. As a result, diffusive mixing of the solution and the poor solvent can be performed instantaneously, so that fine particles with a uniform particle size can be formed, and the formed fine particles are contained in the poor solvent and have no concentration distribution in the reaction channel. Immediate contact with the existing flocculant to form aggregates uniformly.

  A sixth aspect of the present invention according to the fifth aspect is characterized in that the diameter of the reaction channel is 0.5 mm or more and 6 mm or less as an equivalent diameter.

  According to the sixth aspect, the flow of the reaction channel is formed by forming a sandwich-like multi-layer flow in which the thin layers of the solution and the thin layer of the poor solvent are alternately laminated by three or more introduction paths. Even if the path diameter is relatively large, the solution and the poor solvent layer constituting the multi-layer flow itself become a thin layer, so that the diffusion mixing time can be substantially shortened. Therefore, the diameter of the reaction channel can be increased compared to the case where only two introduction channels are used, ie, a solution and a poor solvent. However, it is less likely to cause clogging due to aggregates and unstable flow due to aggregates. The preferred enlargement of the reaction channel is preferably 0.5 mm to 6 mm in equivalent diameter, more preferably 1 mm to 6 mm, and particularly preferably 2 mm to 6 mm.

  A seventh aspect of the present invention provides the reaction channel according to any one of the fourth to sixth aspects, wherein the solution and the poor solvent are merged at the mixing unit inlet of the reaction channel and are then discharged from the mixing unit outlet. The adjusting means for adjusting the total flow rate of the dissolving solution and the poor solvent supplied to the mixing unit is provided so that the staying time of 10 msec or less is provided.

  According to claim 7, in the mixing part, the residence time in the mixing part from the time when the solution and the poor solvent merge at the mixing part inlet of the reaction channel to the time when the mixing part exits from the mixing part outlet is 10 msec or less. Since the total flow rate of the solution to be supplied and the poor solvent is adjusted, non-uniform mixing is unlikely to occur even if the flow path diameter is enlarged.

  As described above, according to the fine particle production method and apparatus of the present invention, aggregate formation can be performed uniformly, so that filtration and redispersion in the subsequent process can be performed with high accuracy and normality. Since the formation and the aggregate formation can be performed at once, the apparatus for producing fine particles can be simplified.

  Hereinafter, preferred embodiments of a method and apparatus for producing fine particles according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a fine particle production apparatus 10 of the present invention. An example of producing organic pigment fine particles using an organic pigment as the fine particle forming material will be described.

  As shown in FIG. 1, the fine particle production apparatus 10 of the present invention mainly includes an apparatus main body 12, a solution pipe 14 for flowing a solution L1 obtained by dissolving an organic pigment in a good solvent to the apparatus main body 12, and the good solvent. A poor solvent pipe 16 that flows the poor solvent L2 that is compatible and does not dissolve the organic pigment to the apparatus main body 12, and each supply means that supplies the solution L1 and the poor solvent L2 to the apparatus main body 12 through the respective pipes 14 and 16. 18 and 20 and addition means 22 for adding a flocculant (for example, hydrochloric acid) to the poor solvent pipe 16.

  The apparatus body 12 is formed by combining a substrate 26 and a cover plate 28, and a reaction groove, a solution introduction groove, and a poor solvent introduction groove are formed on the mating surface of the substrate 26. Then, the cover plate 28 is combined with the substrate 26 to be integrated, whereby the reaction channel 30, the solution introduction channel 32, and the poor solvent introduction channel 34 are formed. In other words, the solution L1 and the poor solvent L2 are introduced into the mixing portion 36 of the reaction flow path 30 so as to merge at the mixing portion 36 of the reaction flow path 30, and the solution L1 and the poor solvent L2 are stacked. A laminar flow L is formed.

  In addition, the two introduction flow paths 32 and 34 are connected to the distal ends of the respective pipes 14 and 16 through the through holes 38 and 38 formed in the lid plate 28, respectively, and the respective pipes 14 and 16. The solution supply means 18 and the poor solvent supply means 20 are connected to the base end portion of these. For example, a microsyringe pump can be suitably used as a supply means for the solution L1 and the poor solvent L2. In this case, it is preferable that the solution supply means 18 and the poor solvent supply means 20 include an adjustment means (not shown) for adjusting the supply amount supplied to the apparatus main body 12.

  As the solution pipe 14 and the poor solvent pipe 16, a resin tube can be preferably used in addition to a metallic pipe. The outlet of the reaction channel 30 is connected to a discharge pipe (not shown) or the like through a through hole 40 formed in the lid plate 28.

  The flocculant addition means 22 includes an addition pipe 23 branched from the poor solvent pipe 16 and a flocculant supply means 24 for feeding the flocculant into the poor solvent pipe 16 via the addition pipe 23. The flocculant supply means 24 may be any device as long as a certain amount of flocculant can be continuously added and supplied from the addition pipe 23 into the poor solvent pipe 16.

  In FIG. 1, the solution L1 and the poor solvent L2 are shown as two introduction channels 32 and 34 for introducing the solution L1 and the poor solvent L2 into the mixing unit 36 of the reaction channel 30, respectively, but as shown in FIGS. The number of the introduction channels 32 and 34 is at least three on the same surface (on the mating surface of the substrate 26 to the lid plate 28), and the solution introduction channel 32 and the poor solvent introduction channel 34 are provided. More preferably, they are arranged alternately.

  FIG. 2 shows the four introduction flow paths 32A, 32B, 34A, 34B branched from the mixing section 36 of the reaction flow path 30 in a fan shape, and the four introduction flow paths 32A, 32B, 34A, 34B are divided. Of these, the flocculant adding means 22 is provided in the two pipes 16A, 16B connected to the poor solvent introduction flow paths 34A, 34B. That is, the first solution introduction flow path 32A and the first poor solvent injection flow path 34A communicated in a Y-shape with an angle θ1 are arranged in the mixing portion 36 of the reaction flow path 30, and on the outside thereof. , The second solution introduction flow path 32B and the second poor solvent injection flow path 34B are arranged in a Y shape at an angle θ2 larger than θ1. Further, the total flow path width of the four introduction flow paths 32A, 32B, 34A, 34B is formed to be larger than the flow path width of the reaction flow path 30. As a result, the four flows that flow through the four introduction flow paths 32A, 32B, 34A, and 34B and merge into the mixing portion 36 of the reaction flow path 30 are contracted with each other to form a tapered flow. A sandwich-like multilayer flow L having a four-layer structure in which thin layers of the liquid L1 and thin layers of the poor solvent L2 are alternately stacked is formed.

  FIG. 3 is a diagram in which five introduction channels 32A, 32B, 32C, 34A, 34B are radially branched from the mixing portion 36 of the reaction channel 30, and the five introduction channels 32A, 32B, 32C, Among the pipes 34A and 34B, the two pipes 16A and 16B connected to the poor solvent introduction flow paths 34A and 34B are provided with a flocculant addition means 22. That is, a first solution introduction flow path 32A is provided on the opposite side of the reaction flow path 30, and the first and second poor solvent introduction flows are arranged on the left and right sides of the first solution introduction flow path 32A. The paths 34A and 34B are arranged in a V shape. Furthermore, the second and third solution introduction channels 32B and 32C are arranged in an inverted V shape on the left and right sides of the reaction channel 30. That is, in the case of the radial type in FIG. 3, the two dissolved solutions L1 are sandwiched so as to push up other joining solutions from the diagonally lower left and right toward the mixing portion 36 of the reaction flow path 30. By this pushing-up, the contraction can be promoted as compared with FIG. The total flow path width of the five introduction flow paths 32A, 32B, 32C, 34A, and 34B was made larger than the flow path width of the reaction flow path 30. As a result, the five flows that flow through the five introduction flow paths 32A, 32B, 32C, 34A, and 34B and are merged into the mixing portion 36 of the reaction flow path 30 are mutually contracted to form a tapered flow. Then, a sandwich-like multilayer flow L having a five-layer structure in which thin layers of the solution L1 and thin layers of the poor solvent L2 are alternately stacked is formed.

  As shown in FIG. 2 and FIG. 3, since the layers of the solution L1 and the poor solvent L2 themselves are thinned by providing three or more introduction channels, the channel diameter of the reaction channel 30 is relatively small. Even if the thickness is increased, the diffusion mixing time can be substantially shortened. Therefore, instantaneous diffusion mixing can be realized even when the diameter of the reaction channel 30 is increased as compared with the case where the number of introduction channels is two, that is, the solution L1 and the poor solvent L2. As a result, even if the process from the formation of fine particles to the formation of aggregates is performed consistently in the reaction channel 30, clogging due to the aggregates and instability of the flow due to the aggregates are unlikely to occur. A preferable range for enlarging the reaction channel 30 is that the channel diameter of the reaction channel 30 is 0.5 mm or more in terms of equivalent diameter, more preferably 1 mm or more, and even more preferably 2 mm or more.

  Here, the importance of instantaneous mixing of the solution L1 and the poor solvent L2 will be described in detail.

  For example, when the solution L1 comes into contact with the poor solvent L2, the precipitation starts immediately. Therefore, if the contact with the poor solvent L2 is spatially and temporally different, the size of the precipitated particles may be distributed. It is not preferable. What is important in order not to cause the distribution is how fast the solution L1 comes into contact with an amount of the poor solvent L2 sufficient to promote precipitation. The most important point for achieving this is the formation of a thin layer of the solution L1.

  Therefore, if a reactor based on the mixing principle is used as in the present invention, the solution L1 is introduced into the confluence field of the reactor and contacts the poor solvent L2 in a nearly uniform state in time and space. . The definition of homogeneity here refers to whether the concentration distribution is evenly mixed in the mixing unit 36 in the time of the same dimension as the speed of reaction started by mixing or the speed of particle formation, or less. It is. Note that the entire flow path does not need to be uniform in concentration, and it is sufficient that there is no difference in the contact time of the poor solvent L2 for the solution L1. Speaking of normal reactions, it is on the order of several milliseconds.

  As for the flow rate ratio between the solution L1 and the poor solvent L2 forming the sandwich-like multi-layer flow L, the lower the ratio of the poor solvent L2 to the solution L1, the higher the concentration of the mixed solution is obtained. It is done. From this point, it is preferable that the flow rate of the liquid on the sandwiching side (for example, the poor solvent L2) is 1 to 10 times the flow rate of the liquid on the sandwiched side (for example, the solution L1). . Furthermore, 2 to 3 times is more preferable, and 2 times is particularly preferable. This mixing method uses the principle of sandwiching a liquid with a liquid, and always uses a sandwich structure that sandwiches from both sides. This may be a structure in which the flow paths are arranged three-dimensionally as well as planarly. The flow rate ratio of L2 to L1 here is defined as the total amount on both sides to be sandwiched. It is particularly preferable in terms of mixing property and productivity that the flow rate ratio of L2 is twice that of L1.

  Further, the total flow rate of the multi-layer flow L (dissolved liquid L1 + poor solvent L2) supplied to the mixing section 36 of the reaction flow path 30 is such that the dissolved liquid L1 and the poor solvent L2 merge at the mixing section inlet of the reaction flow path 30. It is preferable that the staying time in the mixing unit 36 from when the mixing unit exits to the mixing unit exit is 10 msec or less. In order to adjust the total flow rate, the adjusting means provided in the solution supply means 18 and the poor solvent supply means 20 may be controlled.

  Here, the inlet and outlet of the mixing unit 36 in the reaction channel 30 will be described with reference to FIG. 3. The inlet 36A refers to a point where a plurality of channels start to intersect the mixing unit 36, and the outlet 36B includes a plurality of outlets. This refers to the point where the flow paths no longer intersect. Therefore, the mixing portion outlet in the case of FIG. 2 refers to a point where the flow path 32B and the flow path 34B do not intersect the reaction flow path 30.

  And the residence time in the mixing part 36 refers to the time which passes between the entrance 36A and the exit 36B. The residence time of 10 msec or less is defined by the flow of the multilayer flow L formed by the solution L1 and the poor solvent L2. However, the residence time of the solution L1 is important, not the residence time of the poor solvent L2, and the residence time of the solution L1 in the mixing unit 36 is more preferably 10 msec or less. Therefore, when the flow path cross section of the mixing part 36 becomes wide, it is necessary to increase the flow rate supplied to the inlet 36A of the mixing part 36 in order to make the residence time constant.

  The mixing principle of the present invention is to form a thin layer while the solution L1 and the poor solvent L2 are in contact with each other. As can be seen from simple calculations, the thinner the layer, the larger the flow rate of the thin layer. For this reason, the contact opportunity (area) per unit time with which both the liquids L1 and L2 come into contact increases, and unless the interface is constantly updated, the exchange of substances between the two liquids, especially the formation of particles at the interface, is constantly happening. is happening. On the other hand, since the supply of the dispersant cannot be made in time, the tendency for aggregation to occur increases. Of course, this supply rate also changes depending on the concentration of the dispersant. However, if too much dispersant is added, the viscosity of the liquid increases, so that mixing is disadvantageous and it is not preferable to add more than necessary. Experiences to date have shown that it is sufficiently possible to form nanoparticles with high monodispersity if the residence time is 10 msec or less and a certain concentration of dispersant is contained.

  2 and 3, the ratio of the total flow width of the three or more introduction flow paths to the flow width of the reaction flow path is determined by the multi-layer flow. The number of layers, the width of the reaction channel, the time of diffusion mixing performed in the reaction channel, and the like can be set as appropriate. Further, it is only necessary that a plurality of solution introduction flow paths and a plurality of poor solvent introduction flow paths are alternately arranged, and the present invention is not limited to the arrangement shown in FIGS. 2 and 3 do not show the means for supplying the solution L1 and the poor solvent L2, but two (FIG. 2) or three (FIG. 3) solution injection pipes are respectively provided. The solution supply means may be provided individually, or the solution may be divided into two or three solution injection pipes from one solution supply means. The same applies to the supply means of the poor solvent L2.

  The apparatus main body 12 configured as described above is manufactured using precision processing techniques such as micro drilling, micro electric discharge machining, molding using plating, injection molding, dry etching, wet etching, and hot embossing. Can do. As described above, the reaction channel 30 has an equivalent diameter of 0.5 mm or more, so that the reaction channel in a general microreactor for instantaneous diffusion mixing (usually less than 0.5 mm) Therefore, machining techniques using general-purpose lathes and drilling machines can also be used.

  The material of the apparatus main body 12 is not particularly limited as long as the above-described processing technique can be applied. Specifically, metal materials (iron, aluminum, stainless steel, titanium, various metals, etc.), resin materials (acrylic resin, PDMS, etc.), glass (silicon, Pyrex (registered trademark), quartz glass, etc.), quartz Glass or Pyrex (registered trademark) glass subjected to parylene (paraxylene vapor deposition) treatment, or fluorine or hydrocarbon silane coupling treatment can be suitably used.

  Moreover, the apparatus main body 12 can visually observe the contracted flow state which the solution L1 and the poor solvent L2 form in the mixing part 36 of the reaction flow path 30 with a microscope etc. so that it may demonstrate with the microorganisms manufacturing method mentioned later. In addition, it is preferable to manufacture with a transparent material.

  It is preferable to provide a heating means (not shown) for heating the apparatus main body 12. As a heating means, there is a method in which a heater structure such as a metal resistance wire or Polysilicon is built in the apparatus body. In the case of a heater structure such as a metal resistance wire or Polysilicon, this is used for heating, and the temperature is controlled by performing a thermal cycle with natural cooling for cooling. For temperature sensing in this case, in the case of a metal resistance wire, make another same resistance wire, detect the temperature based on the change in the resistance value, and in the case of Polysilicon, use a thermocouple. A method for detecting the temperature by using this method is generally employed. In recent years, by incorporating a temperature control function using a Peltier element into the apparatus main body 12, it is also possible to accurately control the temperature of blood. In any case, the temperature control itself can be performed by a conventional temperature control technique or a new temperature control technique represented by a Peltier element. The optimum method can be selected by combining the selection and the configuration of the external control system.

  Next, the fine particle production method of the present invention will be described using the fine particle production apparatus 10 configured as described above. In the present embodiment, the case where the apparatus main body 12 having the four introduction channels shown in FIG. 2 is used will be described.

  FIG. 4 is a conceptual diagram showing a series of manufacturing flow of organic pigment fine particles.

  First, using the fine particle production apparatus 10 of the present invention, the organic pigment fine particle A forming step and the aggregate forming step of aggregating the formed organic pigment fine particles A to form the aggregate B are performed at a time. That is, the solution L1 and the poor solvent L2 are introduced into the mixing portion 36 of the reaction flow path 30 through the four introduction flow paths 32A, 32B, 34A, 34B, and the poor solvent L2 is added to the poor solvent L2 from the adding means 22. A flocculant C (for example, hydrochloric acid) for agglomerating the organic pigment fine particles A is continuously added to the two poor solvent pipes 16A and 16B in a constant amount. Further, it is preferable to add a dispersant D such as a polymer dispersant to the solution L1. As a result, as shown in FIG. 4A, in the mixing portion 36 of the reaction flow path 30, the solution L1 and the poor solvent L2 flow together to form a thin solution L1 and a thin poor solvent. A sandwich-like multi-layer flow L having a four-layer structure in which L2 is alternately stacked is formed. As the respective layers of the solution L1 and the poor solvent L2 are thinned, the solution L1 and the poor solvent L2 are instantaneously diffused and mixed in the reaction flow path 30 to lower the solubility of the solution L1 and become supersaturated. Therefore, the organic pigment fine particles A are precipitated from the solution L1. The organic pigment fine particles A deposited from the solution L1 come into contact with the flocculant C contained in the poor solvent L2 in the reaction flow path 30 to form an aggregate B. Thereby, monodispersity is good and the organic pigment fine particle A of nanometer size (nm) can be deposited. In addition, since the aggregate formation of the precipitated organic pigment fine particles A is continuously performed in the reaction flow path 30, it is possible to prevent the concentration distribution of the flocculant from being generated. Aggregation B can be formed.

  Next, the dispersion liquid containing the aggregate B is discharged from the outlet of the reaction channel 30 and stored in, for example, a storage container (not shown). In this aggregate B, as shown in FIG. 4 (B), since unnecessary substances such as surplus dispersant D and coagulant C are mixed, as shown in FIG. Unnecessary substances are removed from the aggregate B by filtering with the filter 42.

  Next, a redispersant (for example, a pH adjusting agent) is added to the dispersion liquid containing the aggregate B from which unnecessary substances have been removed, and the aggregate B is redispersed. Thereby, it is possible to produce organic pigment fine particles A having no unnecessary substances and having a good monodispersibility and a nanometer size (nm).

  By applying the fine particle production method and apparatus of the present invention to the production of pigment fine particles, the following effects can be obtained.

  In the present invention, the solution L1 and the poor solvent L2 are contracted with each other to form a sadditch-like multi-layer flow L in which the thin solution L1 and the thin poor solvent L2 are stacked, thereby instantly. Since the organic pigment fine particles A can be precipitated by diffusion mixing, the organic pigment fine particles A having good monodispersibility and nanometer size can be formed.

When the diffusion coefficient is d and the representative distance at which molecules diffuse and reach during time T is L, the relational expression T = L ² / d is established, and the diffusion time is proportional to the square of the distance. For example, the ethanol molecule has a diffusion coefficient D of 0.84 × 10 ⁻³ mm ² / sec (25 ° C.) when the solvent is water, 20 minutes for moving 1 mm, and 1 second for moving 30 μm. This makes instantaneous diffusion mixing impossible. However, if the layer is thinned to 10 μm, the ethanol molecules can move in 0.1 seconds, and if the layer is thinned to 1 μm, the ethanol molecules can move in 0.001 seconds, and if the layer is thinned to 0.1 μm, Ethanol molecules can move in 10 microseconds.

  Thus, in order to instantaneously perform the diffusive mixing, it is extremely important to make the diffusing layers thinner. Further, by forming a multi-layer flow L in which three or more layers of the solution L1 and the poor solvent L2 are alternately stacked, instantaneous diffusion mixing can be realized even if the channel diameter of the reaction channel 30 itself is increased. The channel diameter of the reaction channel 30 can be 0.5 mm or more, preferably 1 mm or more, and more preferably 2 mm or more as described above. Thereby, even if the formation from the formation of the organic pigment fine particles A to the formation of the aggregate B is performed in the reaction flow path 30 at once, it is possible to effectively prevent the reaction flow path 30 from being clogged by the aggregate B. Moreover, since the reaction channel 30 can be enlarged, the manufacturing accuracy for forming the reaction channel 30 can be improved, and the pressure loss in the reaction channel 30 can be prevented from becoming too large. In addition, the organic pigment fine particles can be deposited and aggregated at a time in the reaction flow path 30 so that the precipitation and the aggregation can be configured as one device. After the organic pigment fine particles A are formed in the microreactor, the tank As compared with the conventional case where the aggregate B is formed, the process and apparatus can be simplified.

  Further, in the present invention, since the channel diameter of the reaction channel 30 can be enlarged, the processing capability is improved, and the production efficiency of nanometer-sized organic pigment fine particles with good monodispersibility can be greatly increased. it can.

  The organic pigment used in the embodiment of the present invention is not limited in hue, and can be a magenta pigment, a yellow pigment, or a cyan pigment. Specifically, perylene, perinone, quinacridone, quinacridonequinone, anthraquinone, anthanthrone, benzimidazolone, disazo condensation, disazo, azo, indanthrone, phthalocyanine, triarylcarbonium, dioxazine, aminoanthraquinone, diketopyrrolopyrrole, thioindigo, Magenta pigments such as isoindoline, isoindolinone, pyranthrone or isoviolanthrone pigments or mixtures thereof, yellow pigments, or cyan pigments. More specifically, for example, C.I. I. Pigment red 190 (C.I. No. 71140), C.I. I. Pigment red 224 (C.I. No. 71127), C.I. I. Perylene pigments such as CI Pigment Violet 29 (C.I. No. 71129); I. Pigment orange 43 (C.I. No. 71105) or C.I. I. Perinone pigments such as CI Pigment Red 194 (C.I. No. 71100); I. Pigment violet 19 (C.I. No. 73900), C.I. I. Pigment violet 42, C.I. I. Pigment red 122 (C.I. No. 73915), C.I. I. Pigment red 192, C.I. I. Pigment red 202 (C.I. No. 73907), C.I. I. Pigment Red 207 (C.I. No. 73900, 73906) or C.I. I. Pigment Red 209 (C.I. No. 73905), a quinacridone pigment, C.I. I. Pigment red 206 (C.I. No. 73900/73920), C.I. I. Pigment Orange 48 (C.I. No. 73900/73920), or C.I. I. Quinacridone quinone pigments such as CI Pigment Orange 49 (C.I. No. 73900/73920); I. Anthraquinone pigments such as CI Pigment Yellow 147 (C.I. No. 60645); I. Anthanthrone pigments such as CI Pigment Red 168 (C.I. No. 59300); I. Pigment brown 25 (C.I. No. 12510), C.I. I. Pigment violet 32 (C.I. No. 12517), C.I. I. Pigment yellow 180 (C.I. No. 21290), C.I. I. Pigment Yellow 181 (C.I. No. 11777), C.I. I. Pigment Orange 62 (C.I. No. 11775), or C.I. I. Benzimidazolone pigments such as CI Pigment Red 185 (C.I. No. 12516); I. Pigment yellow 93 (C.I. No. 20710), C.I. I. Pigment yellow 94 (C.I. No. 20038), C.I. I. Pigment yellow 95 (C.I. No. 20034), C.I. I. Pigment yellow 128 (C.I. No. 20037), C.I. I. Pigment yellow 166 (C.I. No. 20035), C.I. I. Pigment orange 34 (C.I. No. 21115), C.I. I. Pigment orange 13 (C.I. No. 21110), C.I. I. Pigment orange 31 (C.I. No. 20055), C.I. I. Pigment red 144 (C.I. No. 20735), C.I. I. Pigment red 166 (C.I. No. 20730), C.I. I. Pigment red 220 (C.I. No. 20055), C.I. I. Pigment red 221 (C.I. No. 20065), C.I. I. Pigment red 242 (C.I. No. 20067), C.I. I. Pigment red 248, C.I. I. Pigment red 262 or C.I. I. Disazo condensation pigments such as C.I. Pigment Brown 23 (C.I. No. 20006); I. Pigment yellow 13 (C.I. No. 21100), C.I. I. Pigment yellow 83 (C.I. No. 21108) or C.I. I. Disazo pigments such as CI Pigment Yellow 188 (C.I. No. 21094); I. Pigment red 187 (C.I. No. 12486), C.I. I. Pigment red 170 (C.I. No. 12475), C.I. I. Pigment yellow 74 (C.I. No. 11714), C.I. I. Pigment red 48 (C.I. No. 15865), C.I. I. Pigment red 53 (C.I. No. 15585), C.I. I. Pigment Orange 64 (C.I. No. 12760) or C.I. I. Azo pigments such as C.I. Pigment Red 247 (C.I. No. 15915), C.I. I. Indanthrone pigments such as CI Pigment Blue 60 (C.I. No. 69800); I. Pigment green 7 (C.I. No. 74260), C.I. I. Pigment Green 36 (C.I. No. 74265), Pigment Green 37 (C.I. No. 74255), Pigment Blue 16 (C.I. No. 74100), C.I. I. Phthalocyanine pigments such as CI Pigment Blue 75 (C.I. No. 74160: 2) or 15 (C.I. No. 74160); I. Pigment blue 56 (C.I. No. 42800), or C.I. I. Triarylcarbonium pigments such as CI Pigment Blue 61 (C.I. No. 42765: 1); I. Pigment violet 23 (C.I. No. 51319), or C.I. I. Dioxazine pigments such as CI Pigment Violet 37 (C.I. No. 51345); I. Aminoanthraquinone pigments such as CI Pigment Red 177 (C.I. No. 65300); I. Pigment red 254 (C.I. No. 56110), C.I. I. Pigment red 255 (C.I. No. 561050), C.I. I. Pigment red 264, C.I. I. Pigment red 272 (C.I. No. 561150), C.I. I. Pigment orange 71 or C.I. I. Diketopyrrolopyrrole pigments such as C.I. Pigment Orange 73; I. Thioindigo pigments such as CI Pigment Red 88 (C.I. No. 73312); I. Pigment yellow 139 (C.I. No. 56298), C.I. I. Pigment Orange 66 (C.I. No. 48210) and the like, isoindoline pigments such as C.I. I. Pigment yellow 109 (C.I. No. 56284), or C.I. I. Pigment Orange 61 (C.I. No. 11295) and other isoindolinone pigments, C.I. I. Pigment Orange 40 (C.I. No. 59700), or C.I. I. Pyranthrone pigments such as CI Pigment Red 216 (C.I. No. 59710), or C.I. I. It is an isoviolanthrone pigment such as CI Pigment Violet 31 (60010).

  Preferred pigments are quinacridone, diketopyrrolopyrrole, disazo condensation, azo, phthalocyanine, and dioxazine pigments.

  As the dispersant used in the present embodiment, the following can be used.

  Anionic dispersants (anionic surfactants) include N-acyl-N-alkyl taurine salts, fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphorus Examples include acid ester salts, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl sulfate ester salts, and the like. Of these, N-acyl-N-alkyltaurine salts are preferred. As the N-acyl-N-alkyl taurine salts, those described in JP-A-3-273067 are preferable. These anionic dispersants can be used alone or in combination of two or more.

  Cationic dispersants (cationic surfactants) include quaternary ammonium salts, alkoxylated polyamines, aliphatic amine polyglycol ethers, aliphatic amines, diamines and polyamines derived from aliphatic amines and fatty alcohols, fatty acids And imidazolines derived from these and salts of these cationic substances. These cationic dispersants can be used singly or in combination of two or more.

  The amphoteric dispersant is a dispersant having both an anion group part in the molecule of the anionic dispersant and a cation group part in the molecule of the cationic dispersant.

  Nonionic dispersants (nonionic surfactants) include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, Examples thereof include glycerin fatty acid esters. Of these, polyoxyethylene alkylaryl ether is preferable. These nonionic dispersants can be used singly or in combination of two or more.

  The organic pigment dispersant is defined as an organic pigment dispersant which is derived from an organic pigment as a parent substance and is produced by chemically modifying the parent structure. For example, sugar-containing organic pigment dispersants, piperidyl-containing organic pigment dispersants, naphthalene or perylene-derived organic pigment dispersants, organic pigment dispersants having a functional group linked to the organic pigment parent structure via a methylene group, polymer chemistry Modified organic pigment parent structure, organic pigment dispersant having sulfonic acid group, organic pigment dispersant having sulfonamide group, organic pigment dispersant having ether group, or carboxylic acid group, carboxylic ester group or carboxamide group And organic pigment dispersants.

  Specific examples of the polymer dispersant include polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyacrylamide, vinyl alcohol-vinyl acetate copolymer, polyvinyl alcohol partially formalized product, polyvinyl Alcohol partially butyralized, vinyl pyrrolidone-vinyl acetate copolymer, polyethylene oxide / propylene oxide block copolymer, polyacrylate, polyvinyl sulfate, poly (4-vinylpyridine) salt, polyamide, polyallylamine salt, condensed naphthalene Sulfonate, Styrene-acrylate copolymer, Styrene-methacrylate copolymer, Acrylate ester-Acrylate copolymer, Acrylate ester Methacrylate copolymer, methacrylate ester-acrylate copolymer, methacrylate ester-methacrylate copolymer, styrene-itaconate copolymer, itaconate-itaconate copolymer, vinyl Examples thereof include naphthalene-acrylate copolymer, vinyl naphthalene-methacrylate copolymer, vinyl naphthalene-itaconate copolymer, cellulose derivative, starch derivative and the like. In addition, natural polymers such as alginate, gelatin, albumin, casein, gum arabic, tonganto gum and lignin sulfonate can also be used. Of these, polyvinylpyrrolidone is preferable. These polymers can be used alone or in combination of two or more. Further, an embodiment in which an anionic dispersant is contained in an aqueous medium and a nonionic dispersant and / or a polymer dispersant is contained in a solution in which an organic pigment is dissolved can be exemplified.

  In order to further improve the uniform dispersibility and storage stability of the organic pigment, the blending amount of the dispersant is preferably in the range of 0.1 to 1000 parts by weight, more preferably 100 parts by weight of the organic pigment. Is in the range of 1 to 500 parts by weight, more preferably in the range of 10 to 250 parts by weight. If the amount is less than 0.1 parts by mass, the dispersion stability of the organic pigment fine particles may not be improved.

  Further, as the flocculant used in the present embodiment, the pigment fine particles are aggregated to form a slurry, paste, powder, granule, cake (lumb), sheet, short fiber, flake, etc. Any material can be used as long as it can be separated by the above-described separation method. Specific examples include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, phosphoric acid, trifluoroacetic acid, dichloro acid, methanesulfonic acid, and the like. Of these, hydrochloric acid, acetic acid, and sulfuric acid are particularly preferable. Further, the amount to be added is preferably as small as possible within the range in which the pigment fine particles aggregate.

  In the fine particle production method described in the present embodiment, the example of producing organic pigment fine particles has been described. However, the fine particle production method and apparatus of the present invention can be applied in various reactions. Other fine particle forming materials include titanium dioxide, calcium carbonate, copper oxide, aluminum oxide, iron oxide, chromium oxide, bismuth vanadate, rutile mixed phase pigment, silver halide, silica, and carbon black. It is not limited to these.

[Example 1]
The present invention will be described in more detail based on the following Example 1, but the present invention is not limited to these Examples.

  In Example 1, organic pigment fine particles were produced using the fine particle production apparatus of the present invention. The solution L1 and the poor solvent L2 in which the organic pigment was dissolved were prepared as follows.

(1) Organic pigment solution L1
・ Easily soluble magenta organic pigment PR122 (2,9-dimethylquinacrine): 50 g
・ Dispersant polyvinylpyrrolidone ... 100g
・ Dimethyl sulfoxide… 1000mL
・ Sodium methoxide 28% methanol solution… 33.3mL
The above ingredients were thoroughly mixed at room temperature and dissolved completely. The solution was passed through a 0.45 μm microfilter to remove impurities such as dust.

  (2) Distilled water was used as the poor solvent L2.

  (3) Hydrochloric acid was used as the flocculant added to the poor solvent.

  (4) As the apparatus, a fine particle production apparatus provided with a rectangular reaction channel 30 of 0.5 mm in both length and width was used. In addition, by using the cover plate 28 of the apparatus main body 12 formed of a transparent resin, the contracted state in the mixing portion 36 of the reaction channel 30 can be observed with a microscope.

(5) Reaction conditions
i) Set flow rate: Using a micro syringe pump (Harvard), the solution L1 was supplied at a constant flow rate of 20 mL / min and the poor solvent L2 was supplied at a constant flow rate of 80 mL / min.

  ii) Reaction temperature: The test was carried out continuously at 18 ° C. for 20 hours.

  The particle size and monodispersity (Mv / Mn) of the produced organic pigment dispersion were measured using Nanotrack UPA-EX150 manufactured by Nikkiso Co., Ltd., and the median average diameter and arithmetic standard deviation were measured.

  As a result, an organic pigment dispersion containing organic pigment fine particles at a concentration of 1% by mass can be obtained as the generated reaction liquid LM. The organic pigment fine particles have a particle size of 20.6 nm and a monodispersity (Mv / Mn ) Was 1.33.

  In this example, the Reynolds number Re in the reaction channel was a laminar flow state of 1700 or less, and the pressure loss in the reaction channel was a low pressure loss of 0.2 MPa.

The perspective view which shows schematic structure of the microparticle manufacturing apparatus of this invention Explanatory drawing explaining an example which provided the four introduction flow paths in the microparticle manufacturing apparatus of this invention Explanatory drawing explaining an example which provided five introduction flow paths in the fine particle manufacturing apparatus of this invention Flow chart illustrating the production flow of the organic pigment fine particles of the present invention Flow chart explaining the manufacturing flow of conventional organic pigment fine particles

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fine particle manufacturing apparatus, 12 ... Apparatus main body, 14, 16 ... Pipe, 18, 20 ... Supply means, 22 ... Coagulant addition means, 23 ... Addition pipe, 24 ... Coagulant supply means, 26 ... Substrate, 28 ... Cover plate, 30 ... reaction channel, 32 ... solution introduction channel, 34 ... poor solvent introduction channel, 36 ... mixing part of reaction channel, L1 ... organic pigment solution, L2 ... poor solvent, A ... organic Pigment fine particles, B ... aggregates, C ... flocculants, D ... dispersants

Claims (7)

A fine particle forming step in which fine particles are precipitated by contacting a solution obtained by dissolving the fine particle forming material in a good solvent and a poor solvent that is compatible with the good solvent and does not dissolve the fine particle forming material;
An aggregate formation step of aggregating the formed fine particles with an aggregating agent to form an aggregate;
A filtration step of filtering the aggregates;
A redispersion step for redispersing the aggregate after filtration into fine particles, and a fine particle production method comprising:
The fine particle formation step and the coagulant are brought into contact with the aggregating agent in the reaction flow channel by forming fine particles while continuously flowing the solution and the poor solvent through the reaction flow channel. A method for producing fine particles, wherein the aggregate formation step is performed at once in the reaction channel.   2. The method for producing fine particles according to claim 1, wherein the poor solvent contains a flocculant in advance, and the poor solvent containing the flocculant is introduced into the reaction channel.   3. The method for producing fine particles according to claim 1, wherein the produced fine particles are organic pigment fine particles. A fine particle forming means for precipitating fine particles by contacting a solution obtained by dissolving the fine particle forming material in a good solvent and a poor solvent that is compatible with the good solvent and does not dissolve the fine particle forming material;
Aggregate forming means for aggregating the formed fine particles with an aggregating agent to form an aggregate;
Filtration means for filtering the aggregates;
Redispersion means for redispersing the aggregate after filtration into fine particles,
The fine particle forming means and the aggregate forming means are configured as one apparatus,
A reaction flow path for mixing the solution and the poor solvent to precipitate and agglomerate fine particles;
A plurality of introduction flow paths that are communicated with the mixing section of the reaction flow path and introduce the solubilized solution and the poor solvent so as to merge in the mixing section to form a multi-layer flow;
And an adding means for adding an aggregating agent to the poor solvent before reaching the mixing portion of the reaction channel.   5. The fine particle production according to claim 4, wherein at least three or more introduction channels are provided on the same surface, and the solution introduction channels and the poor solvent introduction channels are alternately arranged. apparatus.   6. The fine particle manufacturing apparatus according to claim 5, wherein a diameter of the reaction channel is 0.5 mm or more and 6 mm or less as an equivalent diameter.   Supply to the mixing unit so that the residence time in the mixing unit from the time when the solution and the poor solvent merge at the mixing unit inlet of the reaction channel to the time when the mixing unit exits from the mixing unit outlet is 10 msec or less. The fine particle production apparatus according to any one of claims 4 to 6, further comprising an adjusting means for adjusting a total flow rate of the dissolving liquid and the poor solvent.

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