JP2008116503A - Aggregated particle manufacturing method and toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely reduce the size of aggregated particles and narrow the size distribution of aggregated particles by preventing over-aggregation of resin particles in the emulsion aggregation method of aggregating resin particles to obtain aggregated particles. A method for producing aggregated particles that can be provided is provided.
In the dispersion step, resin particles are dispersed in an aqueous medium to produce a slurry of resin particles, and in the aggregation step, aggregation for agglomerating the resin particles to the resin particle slurry obtained in the dispersion step. An agent and hardly soluble inorganic particles are added to aggregate the resin particles. Thereby, the hardly soluble inorganic particles function as a spacer, and the resin particles can be prevented from agglomerating rapidly when the dispersant is added to the slurry of the resin particles.
[Selection] Figure 1

Description

  The present invention relates to a method for producing aggregated particles and a toner.

  An image forming apparatus that forms an image using an electrophotographic system includes a photoconductor, a charging unit, an exposure unit, a developing unit, a transfer unit, and a fixing unit. The charging unit charges the surface of the photoreceptor. The exposure unit irradiates the charged photosensitive member surface with signal light to form an electrostatic latent image corresponding to the image information. The developing means supplies toner in the developer to the electrostatic latent image formed on the surface of the photoreceptor to form a toner image. The transfer unit transfers the toner image formed on the surface of the photoreceptor to a recording medium. The fixing unit fixes the transferred toner image on the recording medium. The cleaning unit cleans the surface of the photoconductor after the toner image is transferred. In such an image forming apparatus, an electrostatic latent image is developed using a one-component developer containing toner or a two-component developer containing toner and a carrier as a developer to form an image. The toner used here is resin particles granulated by dispersing a colorant, a wax as a release agent, etc. in a binder resin as a matrix.

  An image forming apparatus using an electrophotographic system can form an image with good image quality at a high speed and at a low cost. Therefore, the image forming apparatus is used in copying machines, printers, facsimiles, and the like, and has recently been remarkably popular. As a result, the demands on image forming apparatuses have become more severe. In particular, the emphasis is on high definition, high resolution, stable image quality, and high image forming speed of an image formed by the image forming apparatus. In order to achieve these, studies from both the image forming process and the developer are indispensable.

  From the standpoint of developing a high-definition and high-resolution image, it is important to faithfully reproduce the electrostatic latent image from the viewpoint of the developer. Narrowing the width is a problem to be solved. As a method for producing small-diameter toner particles having a narrow particle size distribution width, for example, an emulsion aggregation method is known. According to the emulsion aggregation method, resin particles containing a binder resin and a colorant are generated in water, and the resin particles are aggregated to obtain an aggregate of resin particles. Toner particles that are aggregates of resin particles Is manufactured.

  The toner particle manufacturing method using the emulsion aggregation method includes a salting out / aggregation step, a particle growth stop step, a separation step, and a drying step, and when the volume average particle diameter of the aggregate of resin particles grows to 2 to 9 μm Thus, a production method for performing a particle growth stopping step in which a salting out stopping agent is added has been proposed (for example, see Patent Document 1).

  In the method for producing toner particles disclosed in Patent Document 1, a salting-out agent for salting out / aggregating the resin particles in the resin particle dispersion is first added in the salting-out / aggregating step. As the salting-out agent, a divalent metal salt such as magnesium chloride or a trivalent metal salt such as aluminum chloride is used. When the volume average particle diameter of the resin particles grows to 2 to 9 μm by salting out / aggregating, a salting out stopping agent for stopping salting out / aggregating of the resin particles is added in the particle growth stopping step. A monovalent metal salt such as sodium chloride or potassium chloride is used as the salting out stopper. Thereafter, toner particles are obtained through a separation step of separating the dispersion and the resin particles and a drying step of drying the separated resin particles. In such a method for producing toner particles, since the salting-out stopper is added when the volume average particle diameter of the resin particles is within the above range, the particle diameter of the toner particles can be controlled, and It is said that the particle size distribution width can be narrowed.

  As another method for producing toner particles using the emulsion aggregation method, a resin particle dispersion in which resin particles are dispersed and a colorant dispersion in which a colorant is dispersed are mixed to aggregate the resin particles and the colorant. Then, an inorganic dispersant such as 10 to 70% by weight of calcium carbonate with respect to the toner particles is added to the toner dispersion obtained by fusing and aggregating the obtained aggregate particles, followed by high-speed stirring and filtration. A method for producing toner particles is proposed in which toner particles are obtained by separating and removing inorganic dispersants from toner particles using an acid treatment and decomposing and removing the inorganic dispersant remaining on the toner particle surfaces by acid treatment or the like (for example, Patent Documents). 2).

  In the method for producing toner particles disclosed in Patent Document 2, after the resin particles are aggregated, an inorganic dispersant is added to the toner dispersion to wash the toner particles, thereby reducing the amount of washing water required for washing the toner particles. Can be reduced. In addition, since the residual amount can be reduced by decomposing and removing the inorganic dispersant on the surface of the toner particles, toner particles that have excellent chargeability, developability, and transferability and that maintain these characteristics over a long period of time. It is said that it can be manufactured.

  However, the toner particle production methods disclosed in Patent Documents 1 and 2 have room for improvement in the following points. In the method for producing toner particles disclosed in Patent Document 1, when a salting-out agent for salting out / aggregating the resin particles in the dispersion is added, the resin particles are excessively aggregated too rapidly. Is likely to occur, whereby the aggregates of the resin particles become coarse, and the particle size of the toner particles may be larger than a desired range. Further, when the salting-out agent is added and the resin particles are excessively aggregated, the particle size distribution width of the toner particles may be widened. When the particle size distribution width of the toner particles is widened, the chargeability, developability and transferability of the toner particles are lowered. In particular, there is a problem that high-quality images of a certain level cannot be stably obtained due to non-uniform charging properties.

  Similarly, in the toner particle manufacturing method disclosed in Patent Document 2, a resin particle dispersion in which resin particles are dispersed and a colorant dispersion in which a colorant is dispersed are mixed to aggregate the resin particles and the colorant. Sometimes over-aggregation may occur.

  As described above, the production of toner particles using the emulsion aggregation method still has problems in terms of coarsening of the toner particles caused by the excessive aggregation of the particles and broadening of the particle size distribution width of the toner particles.

JP 2003-66648 A JP-A-10-207120

  An object of the present invention is to prevent the occurrence of excessive aggregation of resin particles in an emulsion aggregation method in which resin particles are aggregated to obtain aggregated particles, and to reduce the size of aggregated particles and the size distribution width of aggregated particles. It is an object of the present invention to provide an aggregated particle manufacturing method and a toner that can be reliably achieved.

The present invention includes a dispersion step of dispersing resin particles in an aqueous medium to obtain a slurry of resin particles;
A method for producing agglomerated particles, comprising: an aggregating step for aggregating resin particles by adding a flocculant for aggregating resin particles and hardly soluble inorganic particles to the slurry of resin particles.

In the present invention, the aggregation process
A slurry of resin particles containing a flocculant and hardly soluble inorganic particles is caused to flow through a coiled pipe under heat and pressure.

In the present invention, the hardly soluble inorganic particles are
It is added at a ratio of 1.5 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the resin particles.

  In the present invention, the hardly soluble inorganic particles are hardly water-soluble alkaline earth metal salts.

  In the present invention, the hardly soluble inorganic particles have a volume average particle diameter of 1.0 μm or less.

  In the present invention, the resin particles have a volume average particle diameter of 0.4 μm or more and 2.0 μm or less.

In the present invention, the resin particles are
It is characterized by being obtained by refining coarse powder containing resin by a high-pressure homogenizer method.

  In the agglomeration step, the present invention is characterized in that a monovalent metal salt is added together with the aggregating agent and the hardly soluble inorganic particles.

The present invention is also characterized in that the resin particles contain polyester.
Further, the present invention is a toner characterized by using resin particles containing a colorant and a release agent together with a synthetic resin and produced by the method for producing aggregated particles of the present invention.

  According to the present invention, in the dispersion step, resin particles are dispersed in an aqueous medium to produce a resin particle slurry, and in the aggregation step, the resin particles are aggregated in the resin particle slurry obtained in the dispersion step. The aggregating agent and hardly soluble inorganic particles are added to agglomerate the resin particles. Thus, aggregated particles that are aggregates of resin particles are produced. In the aggregating step, by adding the hardly soluble inorganic particles together with the aggregating agent, the hardly soluble inorganic particles can be present in the slurry to such an extent that the resin particles are not too close to each other, and the hardly soluble inorganic particles function as a spacer. . Thus, when the dispersant is added to the slurry of resin particles, the resin particles can be prevented from agglomerating rapidly. When the rapid aggregation of the resin particles is prevented, the aggregated particles can be prevented from becoming coarse and the particle size distribution of the aggregated particles from being broadened. The agglomerated particles thus obtained are used, for example, as a toner, and the toner obtained by such a method for producing agglomerated particles has excellent chargeability, developability and transferability, and these characteristics are maintained over a long period of time. The In addition, such toner has particularly high uniformity in charging performance and can stably form a high-quality image.

  According to the invention, in the agglomeration step, a slurry of resin particles containing an aggregating agent and hardly soluble inorganic particles is allowed to flow through the coiled piping under heat and pressure. When such an agglomeration method is used, when the resin fine particles are aggregated to obtain aggregated particles, overaggregation is unlikely to occur, the particle size of the aggregated particles is easy to control, and the resin fine particles can be aggregated even at a relatively low pressure. The scale-up to an industrial scale can be suitably performed.

  According to the invention, the hardly soluble inorganic particles are added at a ratio of 1.5 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the resin particles. When the hardly soluble inorganic particles are added at a ratio within the above range, the function as a spacer can be exhibited so that the resin particles do not come too close to each other. In addition, when the poorly soluble inorganic particles are removed from the toner particles, which are aggregates of resin particles, by water washing, the hardly soluble inorganic particles can be easily removed from the resin particles. Thereby, it is possible to prevent the characteristics of the resin particles to be obtained from changing.

  According to the present invention, the hardly soluble inorganic particles are hardly water-soluble alkaline earth metal salts. Although the hardly water-soluble alkaline earth metal salt is hardly soluble, for example, by stirring the slurry, it is easy to disperse it uniformly in the slurry, so that the function as a spacer can be exhibited more remarkably.

  According to the invention, the hardly soluble inorganic particles have a volume average particle diameter of 1.0 μm or less. When the volume average particle diameter of the hardly soluble inorganic particles is 1.0 μm or less, the hardly soluble inorganic particles can be dispersed in the slurry to the extent that the resin particles are not too close to each other. This function is more remarkably exhibited.

  According to the invention, the resin particles have a volume average particle diameter of 0.4 μm or more and 2.0 μm or less. By aggregating such resin particles, preferable characteristics of the aggregated particles of the present invention become more remarkable. Preferred characteristics include shape uniformity, small particle size, narrow particle size distribution width, and the like.

  Further, according to the present invention, the resin particles are obtained by refining coarse particles containing a resin by a high-pressure homogenizer method. Resin particles obtained by refining coarse powder containing resin using a high-pressure homogenizer method have a particle size smaller than the particle size of the aggregated particles to be obtained, and the particle size of the resin particles varies. Since it is small, variation can be reduced also in the particle diameter of the aggregated particles obtained by aggregating such resin particles.

  Moreover, according to this invention, a monovalent | monohydric metal salt is added with an aggregating agent and a hardly soluble inorganic particle at an aggregation process. When a monovalent metal salt is added together with the flocculant and the hardly soluble inorganic particles, among the resin particles, it is possible to easily aggregate the small particle size resin particles that are in a state that retains electric charge and is relatively difficult to aggregate in the slurry. it can. Thereby, the particle size distribution width of the aggregate of resin particles can be further narrowed.

  In addition, when the fine powder containing resin is refined by the high-pressure homogenizer method, for example, when a component other than a resin is contained in the resin particle, the component other than the resin is almost uniform in the resin of the resin particle for each particle. It is possible to disperse at an appropriate weight ratio. Aggregated particles that are aggregates of such resin particles have a substantially uniform weight ratio and dispersibility in the resin of components other than the resin among a plurality of aggregated particles, and the properties of each aggregated particle are uniform. Therefore, for example, when aggregated particles are used as the toner, components such as a colorant and a release agent can be dispersed in the binder resin at a substantially uniform weight ratio. Thereby, the charging performance among a plurality of particles becomes substantially uniform, and the charging stability is improved. Further, when image formation is performed using toner that is such aggregated particles, the transfer efficiency of the toner image from the photoreceptor to the recording medium, the transfer efficiency from the photoreceptor to the intermediate medium, and the transfer efficiency from the intermediate medium to the recording medium The toner consumption can be reduced. In addition, the occurrence of image defects such as image fog due to toner charging failure is prevented.

  According to the invention, the resin particles contain polyester. Polyester is excellent in transparency, and can give good powder fluidity, low-temperature fixability, secondary color reproducibility and the like to the resulting aggregated particles, and is particularly suitable when the aggregated particles are used as a color toner, for example.

  According to the invention, the toner is manufactured by a method for manufacturing aggregated particles that achieves the above-described effect. Since such a toner has a small diameter and a narrow particle size distribution range, it can exhibit excellent chargeability, developability and transferability. Moreover, these characteristics can be maintained over a long period of time.

  The method for producing agglomerated particles according to the present invention includes a dispersion step of dispersing resin particles in an aqueous medium to obtain a slurry of resin particles, a flocculant for aggregating the resin particles in the resin particle slurry, And an aggregating step of aggregating the resin particles by adding soluble inorganic particles. The agglomerated particles produced by the production method of the present invention are preferably agglomerates of resin particles that are granulated products of synthetic resin. The agglomerated particles produced by the production method of the present invention can be used, for example, as a toner used in an electrophotographic image forming apparatus such as a copying machine, a laser beam printer, or a facsimile. In addition, it can also be used as a filler such as a paint or a coating agent.

  The resin particles can be produced according to a known synthetic resin granulation method, but are preferably particles produced by a high-pressure homogenizer method. In this specification, the high-pressure homogenizer method is a method of granulating a synthetic resin using a high-pressure homogenizer, and the high-pressure homogenizer is an apparatus that pulverizes particles under pressure. As high-pressure homogenizers, commercially available products, those described in patent literature, and the like are known. Examples of commercially available high-pressure homogenizers include microfluidizer (trade name, manufactured by Microfluidics), nanomizer (trade name, manufactured by Nanomizer), and optimizer (trade name, manufactured by Sugino Machine Co., Ltd.). Chamber type high pressure homogenizer, high pressure homogenizer (trade name, manufactured by Rannie), high pressure homogenizer (trade name, manufactured by Sanmaru Machinery Co., Ltd.), high pressure homogenizer (trade name, manufactured by Izumi Food Machinery Co., Ltd.), etc. Can be mentioned. Examples of the high-pressure homogenizer described in the patent literature include those described in International Publication No. 03/059497 pamphlet. Among these, the high-pressure homogenizer described in International Publication No. 03/059497 is preferable. An example of a method for producing resin particles using a high-pressure homogenizer described in International Publication No. 03/059497 is shown in FIG.

  FIG. 1 is a flowchart schematically showing a method for producing resin particles. The manufacturing method shown in FIG. 1 includes a coarse powder preparation process in step s1, a dispersion process in step s2, a coagulation process in step s3, and a cleaning process in step s4. In the present embodiment, the dispersion step of step s2 includes the coarse slurry preparation stage of step s2- (a), the fine graining stage of step 2- (b), and the decompression stage of step 2- (c). Step 2- (d). Moreover, the aggregation process of step s3 includes the flocculant addition stage of step s3- (a), the pressure reduction stage of step s3- (b), and the cooling stage of step s3- (c).

  In the present embodiment, for example, the high-pressure homogenizer 1 shown in FIG. 2 is used in the fine-graining step in Step 2- (b), the decompression step in Step 2- (c), and the cooling step in Step 2- (d). Done with.

  FIG. 2 is a system diagram showing the configuration of the high-pressure homogenizer 1 in a simplified manner. The high-pressure homogenizer 1 includes a tank 2, a feed pump 3, a pressurizing unit 4, a heater 5, a crushing nozzle 6, a decompression module 7, a cooler 8, a pipe 9, and an outlet 10. Including. In the high-pressure homogenizer 1, the tank 2, the feed pump 3, the pressurizing unit 4, the heater 5, the pulverizing nozzle 6, the decompression module 7 and the cooler 8 are connected by a pipe 9 in this order. In the system connected by the pipe 9, the resin particle slurry after being cooled by the cooler 8 may be taken out from the system through the outlet 10, and the resin particle slurry after being cooled by the cooler 8 is again removed. It may be returned to the tank 2 and repeatedly circulated in the direction of the arrow 11. In the dispersion process of step s2, the stage in which the coarse powder slurry passes through the pulverizing nozzle 6 is the fine graining stage in step s2- (b), and the stage in which the coarse slurry passes through the decompression module 7 is the reduced pressure in step s2- (c). The stage passing through the cooler 8 is the cooling stage of step s2- (d).

  The tank 2 is a container-like member having an internal space, and may be referred to as coarse powder (hereinafter simply referred to as “coarse powder” or “synthetic resin coarse powder”) containing a resin obtained in the coarse powder slurry preparation stage of step s2- (a). The coarse powder slurry which is a certain slurry is stored. The feed pump 3 feeds the coarse powder slurry stored in the tank 2 toward the pressurizing unit 4. The pressurizing unit 4 pressurizes the coarse powder slurry supplied from the feed pump 3 and feeds it to the heater 5. For the pressurizing unit 4, for example, a plunger pump including a plunger and a pump driven by suction and discharge by the plunger can be used. The heater 5 heats the coarse powder slurry in a pressurized state supplied from the pressure unit 4. As the heater 5, for example, a heater including a coiled (or spiral) pipe (not shown) and a heating means (not shown) can be used. The coiled pipe is a member having a flow path (not shown) therein, and a pipe-shaped member for allowing the coarse powder slurry to flow around is wound in a coil shape (or a spiral shape). The heating means is provided along the outer peripheral surface of the coiled pipe, and includes a pipe through which water vapor, a heat medium and the like can flow, and a heating medium supply means for supplying the water vapor, the heat medium and the like to the pipe. The heating medium supply means is, for example, a boiler. When the aqueous slurry containing particles is allowed to flow through the coiled piping in the heater 5, centrifugal force and shearing force are applied in a heated and pressurized state. A turbulent flow is generated in the flow path by the simultaneous application of centrifugal force and shearing force. If the particles are sufficiently small particles such as resin particles having a volume average particle size of 0.4 to 2 μm, the particles flow irregularly under the influence of turbulent flow, and the number of collisions between particles is remarkably large. And aggregation occurs. On the other hand, if the particle is a coarse powder having a particle size of about 100 μm, the particle is sufficiently large, so that the particle flows stably in the vicinity of the inner wall surface of the channel by centrifugal force and is not easily affected by turbulent flow. Is unlikely to occur.

  The crushing nozzle 6 crushes the coarse powder into resin particles by causing the coarse powder slurry supplied from the heater 5 to flow in a heated and pressurized state through a flow path formed therein. As the pulverizing nozzle 6, a general pressure-resistant nozzle capable of liquid flow can be used. For example, a multiple nozzle having a plurality of flow paths can be preferably used. The flow paths of the multiple nozzles may be formed on concentric circles centering on the axis of the multiple nozzle, and the plurality of flow paths may be formed substantially parallel to the longitudinal direction of the multiple nozzles. Specific examples of the multi-nozzle include an inlet diameter and an outlet diameter of about 0.05 to 0.35 mm, and one or more, preferably about 1 to 2, channels having a length of 0.5 to 5 cm. It is done. A pressure-resistant nozzle in which the flow path is not formed linearly inside the nozzle can also be used. An example of such a pressure-resistant nozzle is shown in FIG.

  FIG. 3 is a cross-sectional view schematically showing the configuration of the pressure-resistant nozzle 15. The pressure-resistant nozzle 15 has a flow path 16 therein. The flow path 16 is bent in a bowl shape and has at least one collision wall 17 on which coarse powder slurry entering the flow path 16 from the direction of the arrow 18 collides. The coarse powder slurry collides with the collision wall 17 at a substantially right angle, whereby the coarse powder is pulverized, becomes smaller diameter resin particles, and is discharged from the outlet of the pressure-resistant nozzle 15. In the pressure-resistant nozzle 15, the inlet diameter and the outlet diameter are formed to be the same size, but the present invention is not limited to this, and the outlet diameter may be formed smaller than the inlet diameter. In addition, although an exit and an entrance are normally formed in a perfect circle shape, it is not limited to it, You may form in a regular polygon shape. One pressure-resistant nozzle may be provided, or a plurality of pressure-resistant nozzles may be provided.

  For the decompression module 7, it is preferable to use a multistage decompression apparatus described in WO 03/059497. The multistage pressure reducing device includes an inlet passage, an outlet passage, and a multistage pressure reducing passage. One end of the inlet passage is connected to the pipe 9 and the other end is connected to the multistage decompression passage, and introduces slurry containing resin particles in a heated and pressurized state into the multistage decompression passage. The multi-stage decompression passage has one end connected to the inlet passage and the other end connected to the outlet passage, and bubbles generated by bubbling (bubbling) of the slurry in a heated and pressurized state introduced into the inside through the inlet passage. Reduce pressure to prevent it from happening. The multistage decompression passage includes, for example, a plurality of decompression members and a plurality of connecting members. For example, a pipe-shaped member is used as the decompression member. For example, a ring-shaped seal member is used as the connecting member. A multistage decompression passage is configured by connecting a plurality of pipe-shaped members having different inner diameters with a ring-shaped seal member. For example, two to four pipe-shaped members A having the same inner diameter are connected by a ring-shaped seal member from the inlet passage to the outlet passage, and the pipe-shaped member B having an inner diameter about twice as large as the next pipe-shaped member A. Are connected by a ring-shaped seal member, and a multi-stage decompression passage is formed by connecting about 1-3 pipe-shaped members C having an inner diameter smaller than that of the pipe-shaped member B by about 5 to 20%. It is done. When a slurry in a heated and pressurized state is allowed to flow through such a multistage depressurizing passage, the slurry can be depressurized to an atmospheric pressure or a pressurized state close thereto without causing bubbling. A heat exchanging means for circulating the refrigerant or the heat medium may be provided around the multistage depressurizing passage, and cooling or heating may be performed simultaneously with depressurization according to the pressure value applied to the slurry. One end of the outlet passage is connected to the multistage decompression passage, the other end is connected to the pipe 9, and the slurry decompressed by the multistage decompression passage is supplied to the pipe 9. In this multistage pressure reducing device, the inlet diameter and the outlet diameter may be the same, or the outlet diameter may be larger than the inlet diameter.

  In the present embodiment, the decompression module 7 is not limited to the multistage decompression device having the above-described configuration, and for example, a decompression nozzle can be used. FIG. 4 is a longitudinal sectional view schematically showing the configuration of the decompression nozzle 20. The decompression nozzle 20 is formed with a flow path 21 penetrating the inside thereof in the longitudinal direction. An inlet 21a and an outlet 21b of the flow channel 21 are connected to the pipe 9, respectively. The channel 21 is formed so that the inlet diameter is larger than the outlet diameter. Further, in the present embodiment, the flow path 21 has a cross section in a direction perpendicular to the direction of the arrow 22 that is the flow direction of the slurry, gradually becoming smaller from the inlet 21a toward the outlet 21b, and the center of the cross section. (Axis) exists on the same axis parallel to the direction of the arrow 22 (the axis of the decompression nozzle 20). According to the pressure reducing nozzle 20, the slurry in a pressurized and heated state is introduced into the flow channel 21 from the inlet 21 a, and after being subjected to pressure reduction, is discharged toward the pipe 9 from the outlet 21 b. One or more multistage pressure reducing devices or pressure reducing nozzles as described above can be provided. In the case of providing a plurality, they may be provided in series or in parallel.

  As the cooler 8, a general liquid cooler having a pressure-resistant structure can be used. For example, a pipe for circulating the cooling water is provided around the pipe through which the slurry flows, and the slurry is cooled by circulating the cooling water. You can use a cooler to do. Among them, a cooler having a large cooling area such as a serpentine cooler is preferable. Further, it is preferable that the cooling gradient is reduced (or the cooling capacity is lowered) from the cooler inlet toward the cooler outlet. As a result, re-aggregation of the pulverized resin particles is further prevented, so that the coarse powder can be atomized more efficiently and the yield of the resin particles is also improved. One cooler 8 or a plurality of coolers 8 may be provided. When providing two or more, you may provide in series or in parallel. When provided in series, it is preferable to provide a cooler so that the cooling capacity gradually decreases in the slurry flow direction. The slurry discharged from the decompression module 7 and containing the resin particles and in a heated state is introduced into the cooler 8 from an inlet 8a connected to the pipe 9 of the cooler 8, for example, and has a cooling gradient. The inside is cooled and discharged from the outlet 8 b of the cooler 8 to the pipe 9.

  The high pressure homogenizer 1 is commercially available. Specific examples thereof include NANO3000 (trade name, manufactured by Migrain Co., Ltd.). According to the high-pressure homogenizer 1, the coarse powder slurry stored in the tank 2 is introduced into the pulverization nozzle 6 in a heated and pressurized state to pulverize the coarse powder into resin particles, and is discharged from the pulverization nozzle 6. The slurry of resin particles in a heated and pressurized state is introduced into the decompression module 7 to reduce pressure so that no bubbling occurs, and the slurry of resin particles in the heated state discharged from the decompression module 7 is introduced into the cooler 8. To obtain a slurry of resin particles. The resin particle slurry is discharged from the take-out port 10 or circulated again in the tank 2 and subjected to the same pulverization treatment.

[Coarse powder preparation process]
In this step, synthetic resin coarse powder is prepared. At this time, the synthetic resin may contain one or more synthetic resin additives. Synthetic resin coarse powder can be produced, for example, by pulverizing a solidified product of a kneaded material containing one or more synthetic resin and, if necessary, one or more synthetic resin additives.

  The synthetic resin is not particularly limited as long as it can be granulated in a molten state. For example, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyamide, styrenic polymer, (meth) acrylic resin, polyvinyl butyral, silicone Examples thereof include resins, polyurethanes, epoxy resins, phenol resins, xylene resins, rosin-modified resins, terpene resins, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, and aromatic petroleum resins. A synthetic resin can be used individually by 1 type, or can use 2 or more types together. Among these, polyesters, styrene polymers, (meth) acrylic acid polymers, polyurethanes, epoxy resins, and the like that can easily obtain particles having high surface smoothness by wet granulation in water are preferable.

  Known polyesters can be used, and examples thereof include polycondensates of polybasic acids and polyhydric alcohols. As the polybasic acid, those known as polyester monomers can be used, for example, terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid and other aromatic carboxylic acids, maleic anhydride Examples thereof include aliphatic carboxylic acids such as acid, fumaric acid, succinic acid, alkenyl succinic anhydride, and adipic acid, and methyl esterified products of these polybasic acids. A polybasic acid can be used individually by 1 type, or can use 2 or more types together. As the polyhydric alcohol, those known as polyester monomers can be used. For example, aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, glycerin, cyclohexanediol, cyclohexanedimethanol And aromatic diols such as alicyclic polyhydric alcohols such as hydrogenated bisphenol A, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, and the like. A polyhydric alcohol can be used individually by 1 type, or can use 2 or more types together. The polycondensation reaction between the polybasic acid and the polyhydric alcohol can be carried out according to a conventional method. For example, the polybasic acid and the polyhydric alcohol are contacted in the presence or absence of an organic solvent and in the presence of a polycondensation catalyst. The process is terminated when the acid value, softening point, etc. of the polyester to be produced reach a predetermined value. Thereby, polyester is obtained. When a methyl esterified product of a polybasic acid is used as a part of the polybasic acid, a demethanol polycondensation reaction is performed. In this polycondensation reaction, for example, the carboxyl group content at the end of the polyester can be adjusted by appropriately changing the mixing ratio of polybasic acid and polyhydric alcohol, the reaction rate, etc., and thus the properties of the resulting polyester are modified. it can. When trimellitic anhydride is used as the polybasic acid, a modified polyester can also be obtained by easily introducing a carboxyl group into the main chain of the polyester. A self-dispersible polyester in water in which a hydrophilic group such as a carboxyl group or a sulfonic acid group is bonded to the main chain and / or side chain of the polyester can also be used.

  Examples of the styrenic polymer include homopolymers of styrenic monomers and copolymers of styrene monomers and monomers copolymerizable with styrenic monomers. Examples of the styrene monomer include styrene, o-methyl styrene, ethyl styrene, p-methoxy styrene, p-phenyl styrene, 2,4-dimethyl styrene, pn-octyl styrene, pn-decyl styrene, p. -N-dodecyl styrene etc. are mentioned. Examples of monomers copolymerizable with the styrenic monomer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, ( (Meth) acrylates such as n-octyl acrylate, dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, phenyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, etc. ) (Meth) acrylic monomers such as acrylic esters, acrylonitrile, methacrylamide, glycidyl methacrylate, N-methylol acrylamide, N-methylol methacrylamide, 2-hydroxyethyl acrylate, vinyl methyl ether, vinyl ethyl ether Vinyl ethers such as vinyl isobutyl ether, vinyl methyl ketone, vinyl hexyl ketone, vinyl ketones such as methyl isopropenyl ketone, N- vinylpyrrolidone, N- vinyl carbazole, etc. N- vinyl compounds such as N- vinyl indole, and the like. The styrene monomer and the monomer copolymerizable with the styrene monomer can be used alone or in combination of two or more.

  Examples of the (meth) acrylic resin include homopolymers of (meth) acrylic acid esters, copolymers of (meth) acrylic acid esters and monomers copolymerizable with (meth) acrylic acid esters, and the like. As the (meth) acrylic acid esters, the same ones as described above can be used. Examples of the monomer copolymerizable with (meth) acrylic acid esters include (meth) acrylic monomers, vinyl ethers, vinyl ketones, and N-vinyl compounds. These can be the same as those described above. As the (meth) acrylic resin, an acidic group-containing acrylic resin can also be used. The acidic group-containing acrylic resin is, for example, an acrylic resin monomer or an acrylic resin monomer containing an acidic group or a hydrophilic group and / or a vinyl having an acidic group or a hydrophilic group when an acrylic resin monomer or an acrylic resin monomer and a vinyl monomer are polymerized. It can manufacture by using a system monomer together. Known acrylic resin monomers can be used, for example, acrylic acid that may have a substituent, methacrylic acid that may have a substituent, acrylic ester that may have a substituent, and a substituent. Methacrylic acid ester and the like. Acrylic resin monomers can be used alone or in combination of two or more. As the vinyl monomer, known monomers can be used, and examples thereof include styrene, α-methylstyrene, vinyl bromide, vinyl chloride, vinyl acetate, acrylonitrile and methacrylonitrile. A vinyl monomer can be used individually by 1 type, or can use 2 or more types together. Polymerization of the styrene-based polymer and the (meth) acrylic resin is performed by solution polymerization, suspension polymerization, emulsion polymerization or the like using a general radical initiator.

  Although it does not restrict | limit especially as a polyurethane, For example, an acidic group or a basic group containing polyurethane can be used preferably. The acidic group or basic group-containing polyurethane can be produced according to a known method. For example, an acid group or basic group-containing diol, polyol and polyisocyanate may be subjected to addition polymerization. Examples of the acidic group or basic group-containing diol include dimethylolpropionic acid and N-methyldiethanolamine. Examples of the polyol include polyether polyols such as polyethylene glycol, polyester polyols, acrylic polyols, and polybutadiene polyols. Examples of the polyisocyanate include tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Each of these components can be used alone or in combination of two or more. Although it does not restrict | limit especially as an epoxy resin, An acidic group or a basic group containing epoxy resin can be used preferably. An acidic group or basic group-containing epoxy resin is produced, for example, by adding or addition polymerizing a base epoxy resin with a polycarboxylic acid such as adipic acid and trimellitic anhydride or an amine such as dibutylamine or ethylenediamine. be able to.

  Among these synthetic resins, polyester is preferable when the finally obtained aggregated particles are used as a toner. Polyester is excellent in transparency, and can give good powder fluidity, low-temperature fixability, secondary color reproducibility and the like to the aggregated particles, and is therefore suitable as a binder resin for color toners. Further, polyester and acrylic resin may be grafted. Among these synthetic resins, considering the ease of granulating operations to resin particles, kneadability with additives to synthetic resins, making the shape and size of resin particles more uniform, etc. A synthetic resin having a softening point of 150 ° C. or lower is preferable, and a synthetic resin having a softening point of 60 to 150 ° C. is particularly preferable. Among them, a synthetic resin having a weight average molecular weight of 5,000 to 500,000 is preferable. Synthetic resins can be used alone or in combination of two or more. Furthermore, even if it is the same resin, multiple types which are different in any or all of molecular weight, monomer composition, etc. can be used.

In the present invention, a self-dispersing resin may be used as the synthetic resin. The self-dispersing resin is a resin having a hydrophilic group in the molecule and dispersibility with respect to a liquid such as water. Examples of the hydrophilic group include a —COO— group, —SO ₃ — group, —CO group, —OH group, —OSO ₃ — group, —PO ₃ H ₂ group, —PO ₄ — group, and salts thereof. Is mentioned. Among these, an anionic hydrophilic group such as —COO— group and —SO ₃ — group is particularly preferable. Such a self-dispersing resin having one or more hydrophilic groups is dispersed in water without using a dispersing agent or using only a very small amount of a dispersing agent. Although the amount of the hydrophilic group contained in the self-dispersing resin is not particularly limited, it is preferably 0.001 to 0.050 mol, more preferably 0.005 to 0.030 mol with respect to 100 g of the self-dispersing resin. It is. The self-dispersing resin can be produced, for example, by bonding a compound having a hydrophilic group and an unsaturated double bond (hereinafter referred to as “hydrophilic group-containing compound”) to the resin. Bonding of the hydrophilic group-containing compound to the resin can be performed according to a technique such as graft polymerization or block polymerization. The self-dispersing resin can also be produced by polymerizing a hydrophilic group-containing compound or a hydrophilic group-containing compound and a compound copolymerizable therewith.

  Examples of the resin that binds the hydrophilic group-containing compound include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, and styrene- Vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid ester copolymer Polymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, styrene resin such as styrene-vinyl methyl ether copolymer, (meth) acrylic resin, polycarbonate, polyester, Polyethylene, polyethylene Polypropylene, polyvinyl chloride, epoxy resin, urethane modified epoxy resin, silicone modified epoxy resin, rosin modified maleic acid resin, ionomer resin, polyurethane, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral Terpene resin, phenol resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, and the like.

  Examples of the hydrophilic group-containing compound include an unsaturated carboxylic acid compound and an unsaturated sulfonic acid compound. Examples of the unsaturated carboxylic acid compound include unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid and isocrotonic acid, unsaturated dicarboxylic acids such as maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid and citraconic acid, Acid anhydrides such as maleic anhydride and citraconic anhydride, their alkyl esters, dialkyl esters, alkali metal salts, alkaline earth metal salts, ammonium salts and the like can be mentioned. As the unsaturated sulfonic acid compound, for example, styrene sulfonic acids, sulfoalkyl (meth) acrylates, metal salts thereof, ammonium salts, and the like can be used. A hydrophilic group containing compound can be used individually by 1 type, or can use 2 or more types together. Moreover, as a monomer compound other than the hydrophilic group-containing compound, for example, a sulfonic acid compound can be used. Examples of the sulfonic acid compound include sulfoisophthalic acid, sulfoterephthalic acid, sulfophthalic acid, sulfosuccinic acid, sulfobenzoic acid, sulfosalicylic acid, their metal salts, and ammonium salts.

  The synthetic resin used in the present invention may include one or more general synthetic resin additives. Specific examples of the additive for synthetic resin include, for example, inorganic fillers in various shapes (particulate, fibrous, scale-like), colorants, antioxidants, release agents, antistatic agents, charge control agents, Lubricants, heat stabilizers, flame retardants, anti-drip agents, UV absorbers, light stabilizers, light-shielding agents, metal deactivators, anti-aging agents, lubricants, plasticizers, impact strength improvers, compatibilizers, etc. It is done.

  When the finally obtained aggregated particles are used as a toner, a colorant, a release agent, a charge control agent, and the like are preferably contained in the synthetic resin. The colorant is not particularly limited, and for example, organic dyes, organic pigments, inorganic dyes, inorganic pigments, and the like can be used.

  Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, magnetic ferrite, and magnetite.

  Examples of yellow colorants include chrome yellow, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, and Benzidine Yellow. GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, and the like.

  Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment orange 31, C.I. I. And CI Pigment Orange 43.

  Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risor red, pyrazolone red, watching red, calcium salt, lake red C, lake red D, brilliant carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of purple colorants include manganese purple, fast violet B, and methyl violet lake.

  Examples of the blue colorant include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated product, first sky blue, indanthrene blue BC, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. And CI Pigment Blue 60.

  Examples of the green colorant include chrome green, chromium oxide, pigment green B, micalite green lake, final yellow green G, and C.I. I. And CI Pigment Green 7.

  Examples of the white colorant include compounds such as zinc white, titanium oxide, antimony white, and zinc sulfide.

  One colorant can be used alone, or two or more different colorants can be used in combination. Moreover, even if it is the same color, 2 or more types can be used together. Although the content of the colorant in the resin particles is not particularly limited, it is preferably 0.1 to 20% by weight, more preferably 0.2 to 10% by weight, based on the total amount of the resin particles.

  The release agent is not particularly limited. For example, petroleum wax such as paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, low molecular weight polypropylene wax and derivatives thereof. Derivatives, polyolefin polymer waxes (low molecular weight polyethylene wax, etc.) and hydrocarbon synthetic waxes such as derivatives thereof, carnauba wax and derivatives thereof, rice wax and derivatives thereof, candelilla wax and derivatives thereof, plant waxes such as wood wax , Animal waxes such as beeswax and spermaceti, oil-based synthetic waxes such as fatty acid amides and phenol fatty acid esters, long-chain carboxylic acids and their derivatives, long-chain alcohols and their derivatives, silicone-based polymers, higher fatty acids Etc., and the like. Derivatives include oxides, block copolymers of vinyl monomers and waxes, graft modified products of vinyl monomers and waxes, and the like. Among these, a wax having a melting point equal to or higher than the liquid temperature of the aqueous water-soluble dispersant solution in the granulation step is preferable. The content of the release agent in the resin particles is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 to 20% by weight of the total amount of the resin particles.

  The charge control agent is not particularly limited, and those for positive charge control and negative charge control can be used. Examples of charge control agents for positive charge control include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, triphenylmethane Derivatives, guanidine salts, amidine salts and the like can be mentioned. Charge control agents for controlling negative charges include oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, metal salts of naphthenic acid, metal salts of salicylic acid and its derivatives (metals are metal Chromium, zinc, zirconium, etc.), fatty acid soaps, long-chain alkyl carboxylates, resin acid soaps, and the like. A charge control agent can be used individually by 1 type, or can use 2 or more types together as needed. The content of the charge control agent in the resin particles is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.5 to 3% by weight of the total amount of the resin particles.

  The kneaded product can be produced, for example, by dry-mixing one or two or more synthetic resins and, if necessary, synthetic resin additives with a mixer, and kneading the resulting powder mixture with a kneader. The kneading temperature is a temperature equal to or higher than the melting temperature of the binder resin (usually about 80 to 200 ° C., preferably about 100 to 150 ° C.).

  Known mixers can be used, such as Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.), etc. Henschel type mixing apparatus, ongmill (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like.

  A well-known thing can be used also as a kneading machine, for example, common kneading machines, such as a twin-screw extruder, a 3 roll, a laboratory blast mill, can be used. More specifically, for example, TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87, PCM-30 (all of which are trade names, manufactured by Ikegai Co., Ltd.), etc. Extruder, Needex (trade name, manufactured by Mitsui Mining Co., Ltd.) and other open roll type kneaders. Among these, an open roll type kneader is preferable.

  Synthetic resin additives such as colorants may be used as a master batch to uniformly disperse the synthetic resin additive in the kneaded product. Two or more additives for synthetic resin may be used as composite particles. The composite particles can be produced, for example, by adding an appropriate amount of water, lower alcohol or the like to two or more additives for synthetic resin, granulating with a general granulator such as a high speed mill, and drying. Masterbatch and composite particles are mixed into the powder mixture during dry mixing.

  The solidified product can be obtained by cooling the kneaded product. For pulverization of the solidified product, a powder pulverizer such as a cutter mill, a feather mill, or a jet mill is used. Thereby, coarse powder of synthetic resin is obtained. The particle size of the coarse powder is not particularly limited, but is preferably 450 to 1000 μm, more preferably 500 to 800 μm.

[Dispersing process]
In the dispersion step of step s2, resin particles obtained by finely pulverizing the coarse powder obtained in the coarse powder preparation step are dispersed in an aqueous medium to obtain a slurry of resin particles. The dispersion process includes the coarse slurry preparation stage in step s2- (a), the fine graining stage in step 2- (b), the decompression stage in step 2- (c), and the cooling in step 2- (d). Including stages.

(Coarse slurry preparation stage)
In the coarse powder slurry preparation stage of step s2- (a), the synthetic resin coarse powder obtained in the coarse powder preparation step is dispersed in an aqueous medium to obtain a coarse powder slurry. The liquid to be mixed with the synthetic resin coarse powder is not particularly limited as long as it is a liquid that does not dissolve and uniformly disperse the synthetic resin coarse powder, but it is easy to manage the process, waste liquid treatment after all processes, and easy to handle. In view of the above, water is preferable, and water containing a dispersion stabilizer is more preferable. The dispersion stabilizer is preferably added to water before the synthetic resin coarse powder is added to water.

  As the dispersion stabilizer, those commonly used in this field can be used. Among these, a water-soluble polymer dispersion stabilizer is preferable. Examples of the water-soluble polymer dispersion stabilizer include acrylic-based simple substances such as (meth) acrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride, and the like. Mer, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloroacrylate 2-hydroxypropyl, hydroxyl group-containing acrylic monomers such as 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Ester monomers such as oxalic acid esters, vinyl alcohol monomers such as N-methylol acrylamide and N-methylol methacrylamide, ethers with vinyl alcohol, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc. Vinyl alkyl ether monomers, vinyl alkyl ester monomers such as vinyl acetate, vinyl propionate and vinyl butyrate, aromatic vinyl monomers such as styrene, α-methylstyrene and vinyl toluene, acrylamide and methacrylamide Amide monomers such as diacetone acrylamide and these methylol compounds, nitrile monomers such as acrylonitrile and methacrylonitrile, acid chloride monomers such as acrylic acid chloride and methacrylic acid chloride, vinyl pyridi 1 type selected from vinyl nitrogen-containing heterocyclic monomers such as vinylpyrrolidone, vinylimidazole, and ethyleneimine, and crosslinkable monomers such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, and divinylbenzene (Meth) acrylic polymer containing two kinds of hydrophilic monomers, polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, poly Polyoxy such as oxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester Cellulose polymers such as ethylene polymer, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyoxyethylene lauryl phenyl ether sodium sulfate, polyoxyethylene lauryl phenyl ether potassium sulfate, polyoxyethylene nonylphenyl ether sodium sulfate, polyoxyethylene oleyl phenyl Polyoxyalkylene alkyl aryl ether sulfate such as sodium ether sulfate, polyoxyethylene cetyl phenyl ether sodium sulfate, polyoxyethylene lauryl phenyl ether ammonium sulfate, polyoxyethylene nonylphenyl ether ammonium sulfate, polyoxyethylene oleyl phenyl ether ammonium sulfate, polyoxyethylene Lauril -Polyoxyalkylene alkyl ether sulfates such as sodium tersulfate, potassium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene oleyl ether sulfate, sodium polyoxyethylene cetyl ether sulfate, ammonium polyoxyethylene lauryl ether sulfate, ammonium polyoxyethylene oleyl ether sulfate Etc. A dispersion stabilizer can be used individually by 1 type, or can use 2 or more types together. Further, if a slurry of resin particles obtained using an anionic dispersant described later as a dispersion stabilizer is used as it is in the production of aggregated particles, the addition of an anionic dispersant in the aggregation step of the method for producing aggregated particles can be omitted. The addition amount of the dispersion stabilizer is not particularly limited, but is preferably 0.05 to 10% by weight, more preferably 0.1 to 3% by weight of the coarse powder slurry.

  You may add a thickener, surfactant, etc. to a coarse powder slurry with a dispersion stabilizer. The thickener is effective, for example, for further atomization of the coarse powder. The surfactant further improves the dispersibility of the synthetic resin coarse powder in water, for example. The thickener is preferably a polysaccharide thickener selected from synthetic polymer polysaccharides and natural polymer polysaccharides. As the synthetic polymer polysaccharide, known ones can be used, and examples thereof include cationized cellulose, hydroxyethyl cellulose, starch, ionized starch derivatives, and a block polymer of starch and synthetic polymer. Examples of the natural polymer polysaccharide include hyaluronic acid, carrageenan, locust bean gum, xanthan gum, guar gum, gellan gum and the like. A thickener can be used individually by 1 type, or can use 2 or more types together. The addition amount of the thickener is not particularly limited, but is preferably 0.01 to 2% by weight based on the total amount of the coarse powder slurry. Examples of the surfactant include lauryl sulfosuccinate disodium, polyoxyethylene sulfosuccinate lauryl disodium, polyoxyethylene alkyl (C12 to C14) sulfosuccinate disodium, sulfosuccinate polyoxyethylene lauroyl ethanolamide 2 Examples include sodium and sulfosuccinic acid ester salts such as dioctyl sodium sulfosuccinate. Surfactant can be used individually by 1 type, or can use 2 or more types together. The addition amount of the surfactant is not particularly limited, but is preferably 0.05 to 0.2% by weight based on the total amount of the coarse powder slurry.

  The synthetic resin coarse powder and the liquid are mixed using a general mixer, whereby a coarse powder slurry is obtained. Here, the amount of the synthetic resin coarse powder added to the liquid is not particularly limited, but is preferably 3 to 45% by weight, more preferably 5 to 30% by weight of the total amount of the synthetic resin coarse powder and the liquid. Moreover, although mixing with synthetic resin coarse powder and water may be implemented under heating or cooling, it is usually carried out at room temperature. As the mixer, for example, a Henschel type mixing device such as Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), Super Mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.), etc. Ongmill (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like. The coarse powder slurry thus obtained may be directly subjected to the fine graining step, but, for example, as a pretreatment, a general pulverization treatment is performed, and the particle diameter of the synthetic resin coarse powder is preferably around 100 μm, more preferably You may grind | pulverize to 100 micrometers or less. The pulverization process which is the pretreatment is performed, for example, by passing the coarse powder slurry through a general pressure-resistant nozzle under high pressure.

(Fine graining stage)
In the fine granulation stage of step s2- (b), the coarse powder slurry obtained in the coarse powder slurry preparation stage is pulverized under heat and pressure to obtain an aqueous slurry of resin particles. The pressurizing unit 4 and the heater 5 in the high-pressure homogenizer 1 are used for heating and pressurizing the coarse powder slurry. For crushing the coarse powder, a crushing nozzle 6 in the high-pressure homogenizer 1 is used. Although the pressure heating conditions of the coarse powder slurry are not particularly limited, it is preferably pressurized to 50 to 250 MPa and heated to 50 ° C. or higher, and the pressure of the synthetic resin contained in the coarse powder is preferably pressurized to 50 to 250 MPa. More preferably, it is heated to the melting point or higher, and is heated to 50 to 250 MPa and heated to the melting point of the synthetic resin contained in the coarse powder to Tm + 25 ° C. (Tm: 1/2 softening temperature in a synthetic resin flow tester). It is particularly preferred. Here, when the coarse powder contains two or more kinds of synthetic resins, the melting point of the synthetic resin and the ½ softening temperature in the flow tester are both values of the synthetic resin having the highest melting point or ½ softening temperature. It is. If the pressure is less than 50 MPa, the shear energy becomes small and the pulverization may not proceed sufficiently. If it exceeds 250 MPa, the danger is too great in an actual production line, which is not realistic. The coarse powder slurry is introduced into the pulverizing nozzle 6 from the inlet of the pulverizing nozzle 6 at a pressure and temperature in the above-mentioned range. The aqueous slurry discharged from the outlet of the crushing nozzle 6 includes, for example, resin particles, is heated to 60 to Tm + 60 ° C. (Tm is the same as above), and is pressurized to about 5 to 80 MPa.

(Decompression stage)
In the depressurization step of step s2- (c), the aqueous slurry of resin particles in the heated and pressurized state obtained in the atomization step is depressurized to atmospheric pressure or a pressure close thereto while maintaining bubbling. For decompression, the decompression module 7 in the high-pressure homogenizer 1 is used. The aqueous slurry after completion of the depressurization stage includes, for example, resin particles, and the liquid temperature is about 60 to Tm + 60 ° C. In this specification, Tm is the softening point of the resin particles. In this specification, the softening point of the resin particles was measured using a flow characteristic evaluation apparatus (trade name: Flow Tester CFT-100C, manufactured by Shimadzu Corporation). In a flow characteristic evaluation apparatus (flow tester CFT-100C), a load of 10 kgf / cm ² (9.8 × 10 ⁵ Pa) is applied and 1 g of a sample (resin particle) is extruded from a die (nozzle, 1 mm in diameter, 1 mm in length). The sample was heated at a rate of temperature increase of 6 ° C. per minute, and the temperature at which half of the sample flowed out of the die was determined and used as the softening point. Moreover, the glass transition temperature (Tg) of a synthetic resin is calculated | required as follows. Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), according to Japanese Industrial Standard (JIS) K 7121-1987, 1 g of a sample (carboxyl group-containing resin or water-soluble resin) was heated up. The DSC curve was measured by heating at 10 ° C. per minute. Draw the endothermic peak corresponding to the glass transition of the obtained DSC curve at a point where the slope is maximum with respect to the straight line that extends the base line on the high temperature side to the low temperature side and the curve from the rising part of the peak to the vertex. The temperature at the intersection with the tangent was determined as the glass transition temperature (Tg).

(Cooling stage)
In the cooling stage of step s2- (d), the pressure is reduced in the decompression stage, and the aqueous slurry having a liquid temperature of 60 to Tm + 60 ° C. (Tm is the same as above) is cooled to a slurry of about 20 to 40 ° C. For cooling, the cooler 8 of the high-pressure homogenizer 1 is used.

  In this way, an aqueous slurry containing resin particles is obtained. This aqueous slurry may be agglomerated as it is in the next agglomeration step, or resin particles may be isolated from the aqueous slurry, and the resin particles may be newly slurried and agglomerated. In order to isolate the resin particles from the aqueous slurry, general separation means such as filtration and centrifugation are used. In this production method, the resin obtained by appropriately adjusting the temperature and / or pressure applied to the aqueous slurry when the pulverizing nozzle 6 is allowed to flow, the concentration of coarse powder in the aqueous slurry, the number of times of pulverization, and the like. The particle size of the particles can be controlled. In the present invention, considering that the resin particles are aggregated to obtain aggregated particles having an appropriate volume average particle size, the volume average particle size of the resin particles is preferably 2 μm or less, more preferably 0.4 to 2 μm. Adjust each condition.

In the present specification, the volume average particle diameter and the coefficient of variation (CV value) are values obtained as follows. 20 ml of a sample and 1 ml of sodium alkyl ether sulfate are added to 50 ml of an electrolytic solution (trade name: ISOTON-II, manufactured by Beckman Coulter), and ultrasonic waves are applied using an ultrasonic disperser (trade name: UH-50, manufactured by STM). A sample for measurement was prepared by dispersing for 3 minutes at a frequency of 20 kz. This sample for measurement was measured using a particle size distribution measuring device (trade name: Multisizer 3, manufactured by Beckman Coulter, Inc.) under the conditions of aperture diameter: 20 μm, number of measured particles: 50000 count, and volume particle size distribution of sample particles. From these, the standard deviation in volume average particle size and volume particle size distribution was determined. The coefficient of variation (CV value,%) was calculated based on the following formula (1).
CV value (%)
= (Standard deviation in volume particle size distribution / volume average particle diameter) × 100 (1)

[Aggregation process]
In the aggregation step of step s3, a flocculant for aggregating the resin particles and hardly soluble inorganic particles are added to the resin particle slurry obtained in the dispersion step, and the resin particles are aggregated. The aggregation process includes a flocculant addition stage in step s3- (a), a decompression stage in step s3- (b), and a cooling stage in step s3- (c).

  The agglomerated particles are preferably produced by controlling the particle size so that the volume average particle diameter is 3 to 6 μm. Aggregated particles having a volume average particle diameter of 3 to 6 μm, for example, when used as toner, have excellent storage stability under heating in a developing tank, etc., high density and high definition, good image reproducibility, and poor image quality. High-quality images without any problems can be produced stably.

(Flocculant addition stage)
At this stage, the resin particles are aggregated by adding an aggregating agent for aggregating the resin particles to the aqueous slurry of resin particles (hereinafter referred to as “resin particle slurry” unless otherwise specified), and hardly soluble inorganic particles, An aqueous slurry of aggregated particles (hereinafter referred to as “aggregated particle slurry” unless otherwise specified) is obtained. The resin particle concentration in the resin particle slurry is not particularly limited, but is preferably 2 to 40% by weight, more preferably 5 to 20% by weight, based on the total amount of the resin particle slurry. If it is less than 2% by weight, the cohesive force of the resin particles becomes small, and it may be difficult to control the particle size. If it exceeds 40% by weight, overaggregation may occur.

  As the aggregating agent for aggregating the resin particles, a cationic dispersant can be used. Addition of the cationic dispersant decreases the dispersibility of the resin particles in the resin particle slurry. By allowing the resin particle slurry to flow through the pipe-like piping in this state, the aggregation of the resin particles proceeds smoothly without difficulty, and aggregated particles with little variation in shape and particle diameter can be obtained.

  Known cationic dispersants can be used. For example, alkyltrimethylammonium type cationic dispersants, alkylamidoamine type cationic dispersants, alkyldimethylbenzylammonium type cationic dispersants, cationized polysaccharide type cationic dispersants. Preferred are an agent, an alkylbetaine type cationic dispersant, an alkylamide betaine type cationic dispersant, a sulfobetaine type cationic dispersant, an amine oxide type cationic dispersant, and the like. Among these, alkyltrimethylammonium cationic dispersants are more preferable. Specific examples of the alkyl trimethyl ammonium type cationic dispersant include stearyl trimethyl ammonium chloride, tri (polyoxyethylene) stearyl ammonium chloride, lauryl trimethyl ammonium chloride and the like. A cationic dispersing agent can be used individually by 1 type, or can use 2 or more types together. For example, the cationic dispersant is added to the mixed slurry.

  The addition amount of the cationic dispersant is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.1 to 5% by weight of the total amount of the resin particle slurry. When the addition amount is less than 0.1% by weight, the ability to weaken the dispersibility of the resin particles becomes insufficient, and the aggregation of the resin particles may be insufficient. When the addition amount exceeds 5% by weight, the dispersion effect of the cationic dispersant comes to be exhibited, and the aggregation may be insufficient.

  An anionic dispersant may be added to the resin particle slurry together with a cationic dispersant that is a flocculant. The anionic dispersant is preferably added to the resin particle slurry when the synthetic resin that is the matrix component of the resin particles is a resin other than the self-dispersing resin. The anionic dispersant improves the dispersibility of the resin particles in water. Therefore, by adding an anionic dispersant to the resin particle slurry and further adding a cationic dispersant, the aggregation of the resin particles proceeds smoothly and the occurrence of excessive aggregation is prevented, and the particle size distribution width is narrow. Aggregated particles can be produced with good yield. The anionic dispersant may be added to the coarse powder slurry at the stage of preparing the coarse powder slurry.

  Known anionic dispersants can be used, but sulfonic acid type anionic dispersants, sulfate ester type anionic dispersants, polyoxyethylene ether type anionic dispersants, phosphate ester type anionic dispersants, poly Examples include acrylates. As specific examples of the anionic dispersant, for example, sodium dodecylbenzenesulfonate, sodium polyacrylate, polyoxyethylene phenyl ether and the like can be preferably used. An anionic dispersing agent can be used individually by 1 type, or can use 2 or more types together.

  The addition amount of the anionic dispersant is not particularly limited, but is preferably 0.1 to 5% by weight of the total amount of the resin particle slurry. If it is less than 0.1% by weight, the dispersion effect of the resin particles by the anionic dispersant is insufficient, and there is a possibility that overaggregation occurs. Even if it is added in excess of 5% by weight, the dispersion effect does not improve any more. On the contrary, the viscosity of the resin particle slurry is increased, so that the dispersibility of the resin particles is lowered. As a result, overaggregation may occur.

  Further, the use ratio of the cationic dispersant and the anionic dispersant is not particularly limited, and is not particularly limited as long as the use ratio of the anionic dispersant is reduced by the use of the cationic dispersant. However, considering the ease of controlling the particle size of the aggregated particles, the ease of aggregation, preventing the occurrence of overaggregation, and further narrowing the particle size distribution width of the aggregated particles, an anionic dispersant and a cationic dispersant are used. The weight ratio is preferably 10: 1 to 1:10, more preferably 10: 1 to 1: 3, and particularly preferably 5: 1 to 1: 2.

  Moreover, in this invention, a hardly soluble inorganic particle is added with the cation dispersing agent which is a coagulant | flocculant. By adding the hardly soluble inorganic particles together with the flocculant, the hardly soluble inorganic particles can be dispersed and exist in the slurry. The sparingly soluble inorganic particles dispersed and present in the slurry exhibit a function as a spacer to the extent that the resin particles are not too close to each other. Thereby, it is possible to prevent the resin particles from agglomerating rapidly when the dispersant is added to the slurry of the resin particles. When the rapid aggregation of the resin particles is prevented, the aggregated particles can be prevented from becoming coarse and the particle size distribution width of the aggregated particles from being increased. The hardly soluble inorganic particles may be added before the flocculant as long as the dispersion step is completed, or may be added after the flocculant is added. The hardly soluble inorganic particles may be added simultaneously with the flocculant.

  The hardly soluble inorganic particles are particles that are hardly soluble in an aqueous medium, and hardly water-soluble alkaline earth metal salts can be used. The hardly water-soluble alkaline earth metal salt is an alkaline earth metal salt having a solubility in 1 liter of water at 20 ° C. of 3 g or less, preferably 50 mg or less, more preferably 1 mg or more and 30 mg or less.

  Examples of such poorly water-soluble alkaline earth metal salts include calcium carbonate (water solubility 14 to 24 mg / liter; 20 ° C.), calcium phosphate (water solubility 25 mg / liter; 20 ° C.), barium sulfate (water solubility). Solubility 1.15 mg / liter; 20 ° C.) and the like. In addition to these, calcium hydroxide (solubility in water 1.85 g / liter; 0 ° C., 0.77 g / liter; 100 ° C.), calcium sulfate (solubility in water 2.98 g / liter; 20 ° C.) should be used. You can also. Calcium carbonate includes calcite (water solubility 14 mg / liter, 20 ° C.), aragonite (water solubility 15 mg / liter, 20 ° C.), and vaterite (water solubility 24 mg / liter, 20 ° C.). Calcium carbonate includes heavy calcium carbonate, light calcium carbonate, and colloidal calcium carbonate mainly due to the difference in production method. Among these, colloidal calcium carbonate excellent in dispersibility in water is preferable. Although these hardly soluble inorganic particles have a hydrophilic surface, it is easy to stably disperse in the slurry by, for example, stirring the slurry, so that the particle size distribution width of the aggregated particles is further narrowed. can do. Among these hardly soluble inorganic particles, it is optimal to use calcium carbonate.

  Further, the hardly soluble inorganic particles preferably have a volume average particle size of 1.0 μm or less, and more preferably 0.1 μm or more and 1.0 μm or less. When the volume average particle diameter is 1.0 μm or less, the hardly soluble inorganic particles can be dispersed in the slurry to such an extent that the resin particles are not too close to each other, and the function of the hardly soluble inorganic particles as a spacer is further remarkable. To be demonstrated. When the volume average particle diameter exceeds 1.0 μm, it is difficult to remove the hardly soluble inorganic particles from the aggregated particles in the washing step described later. If the hardly soluble inorganic particles cannot be removed from the aggregated particles, the physical properties of the aggregated particles will change. For example, when the aggregated particles are used as the toner, if the hardly soluble inorganic particles remain attached, the chargeability of the toner is lowered and the toner is difficult to be charged. Also, environmental characteristics may change, and charging stability, development stability, transfer stability, and the like due to environmental changes may not be obtained. When the volume average particle diameter is less than 0.1 μm, it is difficult to disperse the hardly soluble inorganic particles in the slurry.

  The hardly soluble inorganic particles are preferably added in a proportion of 1.5 to 5.0 parts by weight with respect to 100 parts by weight of the resin particles, and 2.0 to 4 parts by weight with respect to 100 parts by weight of the resin. More preferably, it is added in a proportion of not more than 0.0 parts by weight. When the ratio of the hardly soluble inorganic particles is within the above range, the function as a spacer can be exhibited so that the resin particles do not come too close to each other. Further, when the hardly soluble inorganic particles are removed from the toner particles, which are aggregates of the resin particles, by washing, the hardly soluble inorganic particles can be easily removed from the resin particles. Thereby, the characteristic change of the resin particle to be obtained can be prevented. When the ratio of the hardly soluble inorganic particles is less than 1.5 parts by weight, the total volume of the hardly soluble inorganic particles becomes too small relative to the total volume of the resin particles in the slurry, and the aggregation of the resin particles due to the addition of the flocculant is caused. There is a possibility that the particle size distribution width of the aggregated particles cannot be narrowed because it cannot be relaxed. If the proportion of the hardly soluble inorganic particles exceeds 5.0 parts by weight, it is difficult to remove the hardly soluble inorganic particles from the aggregated particles in the washing step described later.

  The hardly soluble inorganic particles are preferably added at a ratio of 0.10 wt% to 0.20 wt% of the total amount of the resin particle slurry. When the hardly soluble inorganic particles are less than 0.10% by weight, it becomes difficult to alleviate the aggregation of the resin particles due to the addition of the aggregating agent. When the hardly soluble inorganic particles exceed 0.20% by weight, it becomes difficult to remove the hardly soluble inorganic particles from the aggregated particles in the washing step described later.

  Furthermore, it is preferable to add a monovalent metal salt together with the flocculant and the hardly soluble inorganic particles in the flocculant addition stage of the aggregation step. By adding a monovalent metal salt, it is possible to easily agglomerate small particle size resin particles that retain a charge and are relatively difficult to agglomerate in the slurry. Thereby, the particle size distribution width of the aggregate of resin particles can be further narrowed.

  As the monovalent metal salt, an alkali metal salt such as sodium chloride or potassium chloride is preferably used.

A metal salt having a valence of 2 or more has a strong cohesive force and agglomeration of resin particles also occurs abruptly. As a result, aggregation of the resin particles occurs non-uniformly, and both the particle size distribution and the shape distribution tend to be non-uniform. It is desirable that the aggregation of the resin particles be performed as gently as possible. Therefore, it is preferable to add a monovalent metal salt in that the resin particles can be aggregated as slowly as possible and the small particle size resin particles can be easily aggregated. More preferably, sodium chloride containing (Na ⁺ ) is added.

Furthermore, as a combination of the hardly soluble inorganic particles and the monovalent metal salt, it is preferable that calcium carbonate is used for the hardly soluble inorganic particles and sodium chloride is used for the monovalent metal salt. Although calcium carbonate has a low degree of dissociation and hardly dissolves in water, salt substitution as shown in the following formula (2) occurs in the presence of sodium ion (Na ⁺ ) having a lower ionization tendency than calcium ion (Ca ²⁺ ). .
_{CaCO 3 + 2NaCl → CaCl 2 +} Na 2 CO 3 ... (2)

The reaction of the above formula (2) does not occur abruptly but proceeds gradually, and calcium chloride and calcium carbonate that are easily dissolved in water are produced. Therefore, the degree of aggregation of the resin particles, which is difficult to finely adjust, can be controlled by elution of Ca ²⁺ having a relatively strong cohesive strength from calcium carbonate added in a very small amount.

  The addition amount of the monovalent metal salt is not particularly limited, but is preferably 10 to 25 mol with respect to 1 mol of the hardly soluble inorganic particles. When the monovalent metal salt is less than 10 moles, the amount of the hardly soluble inorganic particles added is too small, and the above-described effects due to the addition of the hardly soluble inorganic particles cannot be exhibited. When the monovalent metal salt exceeds 25 mol, the amount of the hardly soluble inorganic particles added is too large, and the aggregation is excessively advanced, which is not preferable.

  The addition amount of the monovalent metal salt is preferably 1.0 to 5.0% by weight of the total amount of the resin particle slurry. If the addition amount is less than 1.0% by weight, even if a monovalent metal salt is added, the effect of agglomerating the small particle size resin particles may not be obtained. When the addition amount exceeds 5.0% by weight, the addition amount is excessively large and aggregation is excessively advanced, which is not preferable.

  In the flocculant addition stage, the flocculant and the hardly soluble inorganic particles as described above, and a monovalent metal salt used as necessary are added to the resin particle slurry. Next, this slurry is allowed to flow through a coiled pipe under heat and pressure. When an aqueous slurry containing resin particles is caused to flow through a coiled pipe, centrifugal force and shearing force are applied in a heated and pressurized state. A turbulent flow is generated in the flow path by the simultaneous application of centrifugal force and shearing force. If the particles are sufficiently small particles such as resin particles having a volume average particle size of 0.4 to 2 μm, the particles flow irregularly under the influence of turbulent flow, and the number of collisions between particles is remarkably large. And aggregation occurs.

  The resin particle slurry is preferably heated to a glass transition temperature of the resin particles to a softening temperature (° C.) of the resin particles, more preferably 60 to 90 ° C., and preferably 5 to 100 MPa, more preferably 5 to 20 MPa. Is done. When the heating temperature is lower than the glass transition temperature of the resin particles, the resin particles hardly aggregate, and the yield of the aggregated particles may be reduced. If the heating temperature exceeds the softening temperature of the resin particles, over-aggregation may occur even if hardly soluble inorganic particles are added, and particle size control becomes difficult. If the pressure is less than 5 MPa, the resin particle slurry cannot be smoothly passed through the coiled piping. When the pressurization pressure exceeds 100 MPa, aggregation of the resin particles is very difficult to occur.

  The time for circulating the resin particle slurry in the coiled pipe, that is, the treatment time is preferably 5 minutes or more. If the treatment time is less than 5 minutes, the resin particles may not be sufficiently aggregated, and aggregated particles having a uniform size may not be obtained. The treatment time is more preferably 5 minutes or more and 60 minutes or less. When the treatment time exceeds 60 minutes, the aggregated particles may be coarsened.

(Decompression stage)
In the depressurization stage, the aggregated particle slurry in the heated and pressurized state obtained in the coagulant addition stage is depressurized to atmospheric pressure or a pressure close thereto so that foaming (bubbling) due to bumping does not occur. The particle size adjustment is performed in parallel with the decompression. The particle size adjustment is mainly to reduce the diameter of coarse particles. Therefore, the aggregated particle slurry after decompression contains almost no coarse particles, contains aggregated particles having a substantially uniform shape and particle size, and the liquid temperature is about 50 to 80 ° C.

  The reduced pressure of the agglomerated particle slurry is performed using, for example, a reduced pressure nozzle. For example, a decompression nozzle 25 shown in FIG. 5 can be used as the decompression nozzle. FIG. 5 is a longitudinal sectional view schematically showing the configuration of the decompression nozzle 25. A flow path 26 is formed in the decompression nozzle 25 so as to penetrate the inside thereof in the longitudinal direction. One end in the longitudinal direction of the flow path 26 is an inlet 27, and the other end is an outlet 28. Aggregated particle slurry in a heated and pressurized state is introduced into the decompression nozzle 25 from the inlet 27, and the aggregated particle slurry in a heated state is decompressed from the outlet 28 and discharged to the outside of the decompression nozzle 25. The flow path 26 is formed such that its longitudinal axis coincides with the longitudinal axis of the decompression nozzle 25 and its outlet diameter is larger than the inlet diameter. Further, in the present embodiment, the flow path 26 is formed such that portions having a relatively small cross-sectional diameter and a portion having a relatively large cross section in a direction perpendicular to the slurry flow direction (the direction of the arrow 29) are alternately connected. Is done. Further, the vicinity of the inlet 27 of the flow path 26 is a portion having a relatively small cross-sectional diameter, and the vicinity of the outlet 28 is formed to be a portion having a relatively large cross-sectional diameter. When the agglomerated particle slurry in the heated and pressurized state is introduced from the inlet 27 into the flow path 26 of the pressure reducing nozzle 25, the slurry flows through the flow path 26 while receiving the reduced pressure. Only the excessively large particles of the aggregated particles come into contact with the inner wall surface 26a of the flow path 26, and the excess resin particles are dissociated into aggregated particles of an appropriate size and discharged from the outlet 28. . Since the outlet diameter of the flow path 26 is larger than the inlet diameter in the decompression nozzle 25, an appropriate shearing force is applied when the slurry comes into contact with the inner wall surface 26a. For this reason, only agglomerated particles (coarse particles) having an excessively large particle size are subjected to particle size control. On the other hand, when the inlet diameter is larger than the outlet diameter, a strong shearing force is applied, so that the resin particles are detached not only from the aggregated particles having an excessively large particle size but also from other aggregated particles. For this reason, the particle size distribution width of the aggregated particles becomes larger than necessary.

  In this Embodiment, it is not limited to the pressure reduction nozzle 25, The various pressure reduction nozzles which have a flow path formed so that an exit diameter may become larger than an entrance diameter can be used. By making the outlet diameter larger than the inlet diameter, generation of coarse particles due to re-aggregation of the agglomerated particles moderately crushed in the vacuum nozzle is prevented. FIG. 6 is a longitudinal cross-sectional view schematically showing a configuration of a pressure reducing nozzle 30 of another form. The pressure reducing nozzle 30 is formed with a flow path 31 so as to penetrate the inside thereof in the longitudinal direction. One end of the channel 31 is an inlet 32 and the other end is an outlet 33. The flow path 31 is formed such that its longitudinal axis coincides with the longitudinal axis of the pressure reducing nozzle 30 and its outlet diameter is larger than the inlet diameter. Furthermore, in the present embodiment, the flow path 31 is formed so that the cross-sectional diameter in the direction perpendicular to the slurry flow direction (the direction of the arrow 34) increases continuously and gradually from the inlet 32 toward the outlet 33. Is done. The decompression nozzle 30 has the same effect as the decompression nozzle 25. Furthermore, in this Embodiment, it is not limited only to a pressure reduction nozzle, The pressure reduction module 7 in the high pressure homogenizer 1 can also be used.

  In the present embodiment, a plurality of coiled pipes and decompression nozzles or decompression modules are alternately arranged. As a result, aggregation and decompression can be performed alternately and repeatedly, and the shape and particle diameter of the aggregated particles become more uniform.

(Cooling stage)
In the cooling stage, the aggregated particle slurry having a liquid temperature of about 50 to 80 ° C. obtained in the decompression stage is cooled. In the cooling step, the agglomerated particle slurry is cooled to room temperature, for example, and then moved to a washing step.

[Washing process]
In the washing step of step s4, the aggregated particles are obtained by separating the aggregated particles from the aggregated particle slurry, washing, and drying. For separation of the agglomerated particles, general solid-liquid separation means such as filtration, centrifugation, and decantation can be employed. The aggregated particles are washed to remove unaggregated resin particles, anionic dispersants, cationic dispersants, hardly soluble inorganic particles, monovalent metal salts, and the like. Specifically, for example, cleaning is performed using pure water having an electric conductivity of 20 μS / cm or less. The agglomerated particles and pure water are mixed, and the washing with the pure water is repeated until the conductivity of the washing water remaining after separating the agglomerated particles from the mixture becomes 50 μS / cm or less. The aggregated particles of the present invention can be obtained by drying after washing.

  The aggregated particles of the present invention preferably have a volume average particle size of about 3 to 6 μm, have a uniform shape and particle size, and a very narrow particle size distribution width. In order to obtain the aggregated particles of the present invention having a volume average particle diameter of about 3 to 6 μm, for example, it is important to set the treatment time to an optimum time.

  In the method for producing aggregated particles according to the present embodiment, a decompression step may be provided immediately after the cooling step of steps s2- (d) and step s3- (c). This decompression stage is the same as the decompression stage of step s2- (c) or step s3- (b).

  The above-described method for agglomerating resin particles can be performed using, for example, a high-pressure homogenizer described in International Publication No. 03/059497. FIG. 7 is a system diagram schematically showing the configuration of the high-pressure homogenizer 35 for performing the aggregation step in the method for producing aggregated particles. The high-pressure homogenizer 35 is similar to the high-pressure homogenizer 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The high-pressure homogenizer 35 is different from the high-pressure homogenizer 1 in that it does not include the crushing nozzle 6, includes the pressure-reducing modules 36, 38, and 39 different from the pressure-reducing module 7 and includes the coiled pipe 37. The high-pressure homogenizer 35 is a high-pressure homogenizer for aggregating particles rather than crushing the particles. The high-pressure homogenizer 35 includes a tank 2, a feed pump 3, a pressurizing unit 4, a heater 5, a decompression module 36, a coiled pipe 37, a decompression module 38, a cooler 8, and a decompression module 39. The pipe 9 and the outlet 10 are included. In the high-pressure homogenizer 35, the tank 2, the feed pump 3, the pressurizing unit 4, the heater 5, the decompression module 36, the coiled pipe 37, the decompression module 38, the cooler 8 and the decompression module 39 are connected by the pipe 9 in this order. The In the system connected by the pipe 9, the slurry after being cooled by the cooler 8 may be taken out of the system from the take-out port 10, and the slurry after being cooled by the cooler 8 is again put into the tank 2. Returning may be repeated in the direction of the arrow 11.

  As the tank 2, the feed pump 3 and the pressurizing unit 4, those similar to the high pressure homogenizer 1 are used. The resin particle slurry in the tank 2 is fed to the heater 5 in a pressurized state by the feed pump 3 and the pressurizing unit 4. The heater 5 is the same as that in the high-pressure homogenizer 1. That is, the heater 5 including a coiled pipe (not shown) and a heating means (not shown) is used. Both ends of the coiled pipe are connected to the pipe 9 respectively. By flowing through the heater 5, the resin particle slurry is heated and pressurized and supplied to the decompression module 36. For the decompression module 36, for example, a decompression nozzle is used. The decompression nozzle is a nozzle in which a flow path is formed so as to penetrate the inside thereof in the longitudinal direction. One end of the flow path in the longitudinal direction is an inlet, the other end is an outlet, and the outlet diameter is larger than the inlet diameter. The inlet and the outlet are respectively connected to the pipe 9, and the slurry in a heated and pressurized state is introduced into the flow path from the inlet, and the decompressed slurry is discharged from the outlet. Examples of the decompression nozzle include decompression nozzles 25 and 30. Moreover, it can replace with the pressure reduction nozzle and the pressure reduction module 7 in the high pressure homogenizer 1 can also be used. The coarse particles generated in the heater 5 are pulverized by the decompression module 36. In the coiled pipe 37, a resin particle agglomeration step is performed to obtain an agglomerated particle slurry. In the decompression module 38, a decompression process is performed. That is, the aggregated particle slurry is depressurized and only coarse particles are selectively pulverized to control the particle size of the aggregated particles. In the cooler 8, a cooling process is performed, and the aggregated particle slurry is cooled. The cooler 8 is the same as that in the high-pressure homogenizer 1. The cooled aggregated particle slurry is subjected to particle size control again in the decompression module 39, whereby the aggregated particles of the present invention are obtained.

  According to the high-pressure homogenizer 35, first, the resin particle slurry is filled in the tank 2, and after the cationic flocculant is added, the tank 2 is introduced into the coiled piping of the heater 5 to be heated and pressurized. Thereafter, after the coarse particles are crushed by the decompression module 36, centrifugal force and shearing force are applied to the resin particles under heating and pressurization by the coiled pipe 37, and the resin particles are selectively aggregated, and the aggregated particle slurry is formed. Generate. The agglomerated particle slurry is then introduced into the decompression module 38 and subjected to reduced pressure, and the resin particles are detached from the agglomerated particles having an excessive particle size, so that the particle size of the agglomerated particles is made uniform. The agglomerated particle slurry is introduced into the cooler 8 and cooled, and then subjected to particle size control again in the decompression module 39. Thereby, the coagulant addition stage, the pressure reduction stage and the cooling stage of the coagulation process are completed. These series of steps may be repeated. In that case, the agglomerated particle slurry obtained in the cooling stage is recycled to the tank 2 and again subjected to the same treatment.

  FIG. 8 is a system diagram showing a simplified configuration of a high-pressure homogenizer 40 according to another embodiment. The high-pressure homogenizer 40 is similar to the high-pressure homogenizer 35, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The high-pressure homogenizer 40 is characterized in that a coiled pipe 41 and a decompression module 42 are provided between the decompression module 38 and the cooler 8 in the high-pressure homogenizer 35. The coiled pipe 41 is the same as that described in the section of the aggregation step S11. The decompression module 42 is the same as the decompression module 36. According to the high-pressure homogenizer 40, the coiled piping and the decompression module are set as one set, and by providing a plurality of sets, the aggregation of the resin particles and the particle size control (reduction in diameter) of the aggregated particles having an excessive particle size are performed. Can be repeated. Therefore, the particle size of the aggregated particles becomes more uniform, and the particle size distribution width of the finally obtained aggregated particles becomes narrower.

  In the present embodiment, aggregated particles are produced using a high-pressure homogenizer. However, the present invention is not limited thereto, and may be performed using a general mixing device such as a batch type emulsifier or a disperser. .

  Aggregated particles produced by the method for producing aggregated particles as described above have a small particle size and a narrow particle size distribution. Therefore, when such agglomerated particles are used as a toner, the chargeability, developability and transferability of the individual particles are uniform, a high-definition image can be formed, and these characteristics are maintained over a long period of time. .

(Example)
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.

[Example 1]
[Preparation of coarse slurry]
Polyester resin (glass transition temperature Tg: 60 ° C., softening point Tm: 110 ° C.) 87.5 parts, charge control agent (product: TRH, manufactured by Hodogaya Chemical Co., Ltd.), polyester wax (melting point 85 ° C. ) 3 parts and 8 parts of a colorant (KET.BLUE111) were mixed with a mixer (trade name: Henschel mixer, manufactured by Mitsui Mining Co., Ltd.), and the resulting mixture was twin screw extruder (trade name: PCM-30, Melted and kneaded at a cylinder temperature of 145 ° C. and a barrel rotational speed of 300 rpm to prepare a melt-kneaded material of the toner material. The melt-kneaded product was cooled to room temperature, and then coarsely pulverized with a cutter mill (trade name: VM-16, manufactured by Seishin Enterprise Co., Ltd.) to prepare coarse powder having a particle size of 100 μm or less. 40 g of this coarse powder, 13.3 g of xanthan gum, 4 g of sodium dodecylbenzenesulfonate (trade name: LUNOX S-100, anionic dispersant, manufactured by Toho Chemical Co., Ltd.), sulfosuccinic acid type surfactant (trade name: Aerol CT) -1 p, main component: dioctyl sulfosuccinate sodium salt, manufactured by Toho Chemical Industry Co., Ltd. (0.67 g) and water (742 g) were mixed, and the resulting mixture was blended (trade name: New Generation Mixer NGM-1.5TL, stock) Co., Ltd.) and stirred at 2000 rpm for 5 minutes, and then deaerated to prepare a coarse slurry.

[Preparation of resin particle slurry]
800 g of the coarse powder slurry obtained above was put into a tank of a high-pressure homogenizer (trade name: NANO3000, manufactured by Mie Co., Ltd.), the temperature was maintained at 120 ° C. or higher, and the pressure inside the high-pressure homogenizer was increased to 40 MPa. A resin particle slurry containing resin particles having a volume average particle diameter of 2.5 μm was prepared by circulating for a minute. The high-pressure homogenizer used here is the high-pressure homogenizer 1 for grinding shown in FIG. At this time, a pressure of 210 MPa was applied to the slurry in the pressurizing unit 4. Heated to 120 ° C. or higher in the heater 5.

[Preparation of agglomerated particle slurry]
800 g of this resin particle slurry, 100 g of a 20% aqueous solution of stearyltrimethylammonium chloride (trade name: Cotamine 86W, manufactured by Kao Corporation), 1.6 g of calcium carbonate having a volume average particle diameter of 0.112 μm, and 16 g of sodium chloride Was added to a mixer (New Generation Mixer NGM-1.5TL), stirred at 2000 rpm for 5 minutes, and then deaerated to prepare a resin particle slurry containing a cationic dispersant. The entire amount of the resin particle slurry was put into a tank of a high-pressure homogenizer, and the slurry was circulated in the high-pressure homogenizer for 10 minutes under heating and pressurization at 70 ° C. and 13 MPa to produce an agglomerated particle slurry. The high-pressure homogenizer used here is a high-pressure homogenizer 40 for particle aggregation shown in FIG. 8 in which a high-pressure homogenizer (trade name: NANO3000, manufactured by Mie Co., Ltd.) is partially changed. The coiled piping in the heater 5 is the same as that in the high-pressure homogenizer 1 for pulverization used above.

  By filtering the aggregated particle slurry obtained above, the aggregated particles were taken out and washed with water 5 times, and then the aggregated particles were dried with hot air at 75 ° C. to obtain the aggregated particles of Example 1.

[Example 2]
Aggregated particles of Example 2 were obtained in the same manner as in Example 1 except that in the preparation of the agglomerated particle slurry, the treatment time, which was the time for circulating the slurry in the high-pressure homogenizer, was 20 minutes.

Example 3
Aggregated particles of Example 3 were obtained in the same manner as in Example 1 except that the treatment time was 30 minutes in the preparation of the agglomerated particle slurry.

Example 4
Aggregated particles of Example 4 were obtained in the same manner as in Example 1 except that the treatment time was 60 minutes in the preparation of the agglomerated particle slurry.

[Comparative Example 1]
Aggregated particles of Comparative Example 1 were obtained in the same manner as in Example 1 except that calcium carbonate was not added in the preparation of the agglomerated particle slurry.

[Comparative Example 2]
Aggregated particles of Comparative Example 2 were obtained in the same manner as in Example 1 except that calcium carbonate was not added and the treatment time was 20 minutes in the preparation of the agglomerated particle slurry.

[Comparative Example 3]
Aggregated particles of Comparative Example 3 were obtained in the same manner as in Example 1 except that calcium carbonate was not added and the treatment time was 30 minutes in the preparation of the agglomerated particle slurry.

[Comparative Example 4]
Aggregated particles of Comparative Example 4 were obtained in the same manner as in Example 1 except that calcium carbonate was not added and the treatment time was 60 minutes in the preparation of the agglomerated particle slurry.

  Table 1 shows the volume average particle diameter (μm), coefficient of variation (CV value), and yield (%) of the aggregated particles obtained in Examples 1 to 4 and Comparative Examples 1 to 4. The yield (%) is a value obtained by dividing the weight of the obtained aggregated particles by the weight of the mixture before melt kneading. The amount of calcium carbonate added is the weight (parts) of calcium carbonate relative to 100 parts by weight of the resin particles.

  From Table 1, the agglomerated particles of Examples 1 to 4 have a volume average particle diameter in the range of 3 to 6 μm, and agglomerated particles having a small particle diameter are obtained as compared with the case where calcium carbonate, which is a hardly soluble inorganic particle, is not added. It is clear that Further, it can be seen that when the treatment time is as long as 90 minutes or more, the variation coefficient is as small as 23.3 or less, and aggregated particles having a uniform shape can be obtained.

It is a flowchart which shows the manufacturing method of a resin particle roughly. 1 is a system diagram showing a simplified configuration of a high-pressure homogenizer 1. FIG. 2 is a cross-sectional view schematically showing a configuration of a pressure-resistant nozzle 15. FIG. 2 is a longitudinal sectional view schematically showing a configuration of a decompression nozzle 20. FIG. 3 is a longitudinal sectional view schematically showing a configuration of a decompression nozzle 25. FIG. It is a longitudinal direction sectional view showing typically the composition of decompression nozzle 30 of another form. It is a systematic diagram which simplifies and shows the structure of the high-pressure homogenizer 35 for implementing the aggregation process in the manufacturing method of an aggregated particle. It is a systematic diagram which simplifies and shows the structure of the high voltage | pressure homogenizer 40 of another form.

Explanation of symbols

1, 35, 40 High-pressure homogenizer 2 Tank 3 Feed pump 4 Pressure unit 5 Heater 6 Grinding nozzle 7, 36, 38, 42, 44, 45 Depressurization module 8 Cooling machine
9 Piping 10 Outlet 15 Pressure-resistant nozzle 16, 21, 26, 31 Flow path 17 Collision wall 20, 25, 30 Depressurizing nozzle 37, 41 Coiled piping

Claims (10)

A dispersion step of dispersing resin particles in an aqueous medium to obtain a slurry of resin particles;
A method for producing agglomerated particles, comprising: an aggregating step for aggregating resin particles by adding a flocculant for agglomerating resin particles and hardly soluble inorganic particles to the slurry of resin particles. In the aggregation process,
The method for producing agglomerated particles according to claim 1, wherein a slurry of resin particles containing an aggregating agent and hardly soluble inorganic particles is allowed to flow through a coiled pipe under heating and pressure. Slightly soluble inorganic particles
The method for producing agglomerated particles according to claim 1 or 2, wherein the resin particles are added at a ratio of 1.5 parts by weight or more and 5.0 parts by weight or less based on 100 parts by weight of the resin particles.   The method for producing agglomerated particles according to any one of claims 1 to 3, wherein the hardly soluble inorganic particles are hardly water-soluble alkaline earth metal salts.   The method for producing agglomerated particles according to any one of claims 1 to 4, wherein the hardly soluble inorganic particles have a volume average particle diameter of 1.0 µm or less.   The method for producing aggregated particles according to any one of claims 1 to 5, wherein the resin particles have a volume average particle diameter of 0.4 µm or more and 2.0 µm or less. Resin particles
The method for producing agglomerated particles according to any one of claims 1 to 6, which is obtained by finely granulating a coarse powder containing a resin by a high-pressure homogenizer method.   The method for producing aggregated particles according to any one of claims 1 to 7, wherein in the aggregation step, a monovalent metal salt is added together with the aggregating agent and the hardly soluble inorganic particles.   The method for producing aggregated particles according to any one of claims 1 to 8, wherein the resin particles contain polyester.   A toner comprising resin particles containing a colorant and a release agent together with a synthetic resin and produced by the method for producing aggregated particles according to claim 1.

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