JP2006257354A - Method for producing resin-containing grain, and toner for electrophotography using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a resin-containing grain that is not restricted from the sort of the resin to be used as a raw material of the grain, can reduce environmental load, and can protect from the development of rough and large grain, and can have a narrow grain diameter distribution. <P>SOLUTION: The resin-containing grain is produced by obtaining a dispersion 3 by dispersing a raw material 7 containing at least a resin, a supercritical insoluble grain 4, and a supercritical soluble organic compound 5 in a hydrophobic medium 6, feeding the dispersion 3 into a supercritical solution 1, stirring the solution while heating, and then by reducing the pressure of the supercritical solution 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing resin-containing particles and an electrophotographic toner using the same.

  Resin-containing particles are widely used in matting agents for paints, additives for light diffusion, electrophotographic toners, insulating fillers, crystal nucleating agents, chromatographic fillers, and the like. Among them, the polyester-based resin-containing particles have high utility value because they have many advantages such as light weight, high strength, high transparency, and low cost.

  Conventionally, as a method for producing these resin-containing particles, a production method called a polymerization method such as a suspension polymerization method or an emulsion polymerization method has been proposed. The polymerization method is excellent in shape control because the diameter of particles to be produced can be reduced and from spherical particles to irregularly shaped particles can be produced. However, in the production of particles by the polymerization method, a large amount of waste liquid containing suspension stabilizers, surfactants, polymerization initiators and the like is generated, and equipment for treating the waste liquid is required, and the cost of waste liquid treatment is high. There is a problem of becoming. In addition, since polymerization is involved during granulation, there is a problem that the resin used as a raw material for the resin-containing particles is limited to an acrylic resin.

  As a method that does not involve polymerization during granulation, a submerged drying method is known. In the liquid drying method, it is possible to produce a polyester-based resin that cannot be produced by the polymerization method. However, as with the polymerization method, the wastewater treatment, adverse effects on the environment due to the use of a solvent for dissolving the resin, operation There are problems such as complications.

  As a method for producing resin-containing particles that solves such a problem, a method of producing resin-containing particles using a supercritical fluid or a subcritical fluid has been proposed (see, for example, Patent Documents 1 to 3). Supercritical fluids or subcritical fluids (hereinafter, unless otherwise specified, subcritical fluid states are also included in supercritical fluids) are generally very powerful in dissolving objects, and are subject to changes in temperature and pressure. , It has the property that the dissolving power of the substance can be changed greatly. Therefore, the supercritical fluid is a very excellent solvent when used as a reaction solvent and an extraction solvent, and has a small environmental load. In recent years, supercritical fluids have been actively studied in the fields of material separation, extraction and purification. Examples of using a supercritical fluid include extraction of caffeine in coffee, separation and extraction of waste, production of fine particles, and the like. In the methods disclosed in Patent Documents 1 to 3, a fluid such as water or methanol is used as a supercritical fluid for softening the resin to produce resin-containing particles.

  However, in order to make a fluid such as water and methanol into a supercritical fluid state, it is necessary to set the temperature to 374 ° C. or higher for water and 240 ° C. or higher for methanol. Examples disclosed in Patent Documents 1 to 3 However, this method is not practical in view of industrialization. When the fluid is heated to such a high temperature, there is a concern about the thermal decomposition of the resin contained in the raw material of the resin-containing particles. In addition, since no solvent is used to dissolve the resin, the environmental load is small. However, when the supercritical fluid is decompressed to precipitate the resin-containing particles, the solvent of water or methanol is liquefied, and waste liquid treatment of this liquefied solvent is performed. Is required.

  Carbon dioxide is well known as a substance that can be a supercritical fluid even at a relatively low temperature. Since the temperature at which carbon dioxide becomes a supercritical fluid or subcritical fluid is as low as about 31 ° C., the cost of energy required for heating can be reduced. Further, when carbon dioxide is used as a supercritical fluid, carbon dioxide is vaporized when the resin-containing particles are deposited under reduced pressure, so that there is no need for waste liquid treatment.

  In the methods disclosed in Patent Documents 1 to 3, carbon dioxide can be applied as a supercritical fluid or a subcritical fluid. However, when carbon dioxide is used as the supercritical fluid in the methods disclosed in Patent Documents 1 to 3, the dispersibility of the polymer resin contained in the raw material in the supercritical fluid is poor, and the resin is in the supercritical fluid. The problem of agglomeration and generation of coarse particles arises.

  Therefore, a method for producing resin-containing particles that uses carbon dioxide that can be used as a supercritical fluid even at low temperatures and that can prevent the generation of coarse particles has been proposed (see, for example, Patent Document 4). The method disclosed in Patent Document 4 is a method of coating a core resin of an organic substance with a polymer resin such as an acrylic resin using a rapid expansion method (RESS (Rapid Expansion of Supercritical Solution) method). In this method, in order to improve the dispersibility of the resin in the supercritical fluid, a cosolvent that lowers the viscosity of the resin is introduced into the supercritical fluid to produce resin-containing particles.

  When such a co-solvent is added, the resin can be dissolved in the supercritical fluid and the dispersibility can be improved, so that resin-containing particles having a narrow particle size distribution can be produced without generating coarse particles. It is said. However, in the method disclosed in Patent Document 4, since the resin contained in the raw material of the resin-containing particles needs to be dissolved in carbon dioxide in a supercritical fluid state, the types of resins that can be used are limited, and the application range is limited. There is a problem that it is limited.

  Therefore, a method has been proposed that can produce resin-containing particles containing a resin that is insoluble in a supercritical fluid (see, for example, Patent Document 5). According to the method disclosed in Patent Document 5, an organic dispersant such as a fluorine-based or silicone-based resin that disperses a resin in a supercritical fluid is added to the supercritical fluid, and the resin is emulsified in the supercritical fluid. Since the dispersibility of the resin can be enhanced, resin-containing particles containing the resin can be produced even with a resin that does not dissolve in the supercritical fluid.

  However, even when such an organic dispersant is used, the dispersibility of the resin in the supercritical fluid is not sufficient, and the resulting resin-containing particles have a wide particle size distribution and include coarse particles. Therefore, it is desired to solve such a problem.

JP 2004-143405 A JP 2004-143406 A JP 2004-143407 A JP-A-11-197494 JP 2004-144778 A

  The object of the present invention is not to limit the type of resin used as a raw material for resin-containing particles, but can reduce the environmental load, and further prevent the generation of coarse particles and narrow the particle size distribution. It is to provide a method for producing resin-containing particles that can be produced and an electrophotographic toner using the same.

The present invention includes a step of introducing a raw material containing at least a resin and a dispersant for dispersing the raw material in the supercritical fluid or subcritical fluid into the supercritical fluid or subcritical fluid and stirring the mixture while heating, Reducing the pressure of the critical fluid or subcritical fluid, a method for producing resin-containing particles,
The dispersant is
A method for producing resin-containing particles, characterized in that particles that are insoluble in a supercritical fluid or subcritical fluid and organic substances that are soluble in the supercritical fluid or subcritical fluid are dispersed in a hydrophobic medium. It is.

In the present invention, the hydrophobic medium is
The resin contained in the raw material is not dissolved.

In the present invention, the particles that are insoluble in the supercritical fluid or subcritical fluid are:
It contains at least one selected from silicon dioxide, titanium dioxide and organic pigments.

In the present invention, the particles that are insoluble in the supercritical fluid or subcritical fluid are:
The surface is previously hydrophobized.

Further, the present invention provides an organic substance that is soluble in a supercritical fluid or subcritical fluid.
It is characterized by including 1 or more types selected from a fluororesin, a silicone resin, and an acrylic resin.

In the present invention, the supercritical fluid or subcritical fluid is
It is characterized by being carbon dioxide.

In the present invention, the raw material is
It contains a pigment and a wax.

  According to another aspect of the present invention, there is provided an electrophotographic toner produced by the method for producing resin-containing particles according to any one of the above.

  According to the present invention, a step of charging a raw material containing at least a resin and a dispersant for dispersing the raw material in the supercritical fluid or subcritical fluid into the supercritical fluid or subcritical fluid and stirring while heating. Reducing the pressure of the supercritical fluid or subcritical fluid, wherein the dispersant is insoluble in the supercritical fluid or subcritical fluid, and the organic material is soluble in the supercritical fluid or subcritical fluid; There is provided a method for producing resin-containing particles, characterized in that is dispersed in a hydrophobic medium. Particles that are insoluble in the supercritical fluid or subcritical fluid contained in the dispersant and organic substances that are soluble in the supercritical fluid or subcritical fluid can also be used alone in the supercritical fluid or subcritical fluid. The resin can be emulsified and the resin-containing particles can be atomized. In the present invention, by using a dispersant in which both are dispersed in a hydrophobic medium, the dispersant is an organic substance that is soluble in the supercritical fluid or subcritical fluid. The particles are insoluble in the fluid, and the optimum orientation state is achieved such that the hydrophobic group is arranged outward. As a result, for example, the dispersant can be stably dispersed in the supercritical fluid or subcritical fluid of carbon dioxide, which is a hydrophobic medium, and the dispersibility of the dispersant is increased, so that it exists in an emulsified state. Fusion of the resins in the supercritical fluid or subcritical fluid can be prevented, and the generation of coarse particles can be prevented and the particle size distribution of the resin-containing particles can be narrowed. Further, since it is not necessary to dissolve the resin in the supercritical fluid or subcritical fluid, the type of resin that can be used is not limited. Furthermore, since the generation of waste water can be eliminated by selecting a substance that is vaporized by decompression processing, for example, as a supercritical fluid or a subcritical fluid, the problem of waste water treatment does not occur, and the environmental load can be reduced. .

  According to the present invention, the hydrophobic medium does not dissolve the resin contained in the raw material. When a dispersant containing such a hydrophobic medium is used, it is possible to prevent fusion between the resins that are generated when the resin is dissolved in the hydrophobic medium, thereby further preventing the generation of coarse particles. The particle size distribution of the resin-containing particles can be narrowed.

  According to the invention, the particles that are insoluble in the supercritical fluid or subcritical fluid contain one or more selected from silicon dioxide, titanium dioxide, and organic pigments. By selecting such a substance, the dispersibility as a dispersant can be increased, and the resin-containing particles can be more efficiently reduced in diameter.

  According to the present invention, the surface of particles that are insoluble in the supercritical fluid or subcritical fluid is previously hydrophobized. Such a dispersant has a higher dispersibility in a supercritical fluid or a subcritical fluid, and can further enhance the dispersibility as a dispersant, so that the resin-containing particles can be more efficiently reduced in diameter. be able to.

  According to the invention, the organic substance that is soluble in the supercritical fluid or the subcritical fluid includes one or more selected from a fluororesin, a silicone resin, and an acrylic resin. Since such substances are easily dissolved in supercritical fluids or subcritical fluids, it is possible to increase the dispersibility as a dispersant, reduce the size of the particles to be produced, and narrow the particle size distribution of the resulting resin-containing particles. it can.

  According to the invention, carbon dioxide is used as the supercritical fluid or subcritical fluid. Since the temperature at which carbon dioxide is converted to a supercritical fluid or subcritical fluid is as low as about 31 ° C., the cost of energy required for heating can be reduced. Further, when the particles are deposited by decompression, since the supercritical fluid can be discharged as a harmless carbon dioxide gas, it is not necessary to perform waste liquid treatment, and the resin-containing particles can be produced by a method having a small environmental load.

  According to the invention, the raw material includes a pigment and a wax. Since resin-containing particles having a small particle size and a narrow particle size distribution can be produced even using such a raw material containing a resin, a pigment, and a wax, it is possible to produce resin-containing particles that can be applied to a wide range of fields. it can.

  According to the invention, there is provided an electrophotographic toner produced by the method for producing resin-containing particles according to any one of the above. The toner for electrophotography produced by such a method has a small particle size and a narrow particle size distribution, and can realize energy saving at the time of production.

  In the method for producing resin-containing particles of the present invention, at least a raw material containing a resin and a dispersant for dispersing the raw material in the supercritical fluid or subcritical fluid are charged into the supercritical fluid or subcritical fluid and heated. And the step of reducing the pressure of the supercritical fluid or subcritical fluid (hereinafter referred to as the depressurization step), and the dispersant is supercritical fluid or subcritical Particles that are insoluble in fluid and organic substances that are soluble in supercritical fluid or subcritical fluid are dispersed in a hydrophobic medium.

  When the temperature and pressure of the substance are set to a certain condition (critical point) or more, a fluid in which the density of gas and liquid is equal is obtained. A fluid under temperature and pressure above the critical point is called a supercritical fluid. In addition, a fluid close to a supercritical fluid may be obtained even below the critical point, and such a fluid is called a subcritical fluid.

  In the supercritical fluid or subcritical fluid (hereinafter, unless otherwise specified, the state of the subcritical fluid is also included in the supercritical fluid), both the properties of gas and liquid appear. For example, the density is about several hundred times the density of the gas and close to the density of the liquid, and the viscosity is about 1/10 to 1/100 of the viscosity of the liquid and close to the viscosity of the gas. Further, the diffusion coefficient is as small as 1/10 to 1/100 of the diffusion coefficient of the liquid, and the thermal conductivity is close to the thermal conductivity of the liquid and is about 100 times the thermal conductivity of the gas.

  A supercritical fluid generally has a very large power for dissolving an object, and has a property that can greatly change the dissolving power of a substance by changing temperature and pressure. Therefore, when used as a reaction solvent and an extraction solvent, a supercritical fluid is a very excellent solvent.

  FIG. 1 is a diagram for explaining a method for producing resin-containing particles according to one embodiment of the present invention. In the heating and stirring step, a raw material 7 containing at least a resin, a dispersant 3 for dispersing the raw material 7 in the supercritical fluid 1, and preferably a cosolvent 2 are charged into a reaction vessel 8 filled with the supercritical fluid 1. And stir while heating.

  Examples of substances that can be used as the supercritical fluid 1 include carbon dioxide, nitrogen, methane, ethane, trifluoromethane, ammonia, trifluorochloromethane, methanol, ethanol, and water.

  Among the substances exemplified above, carbon dioxide having a critical temperature close to room temperature and having advantages such as nonpolarity, nonflammability, harmlessness, safety, and low cost is particularly preferable. The critical point of carbon dioxide is a temperature of 31.1 ° C. and a pressure of 7.4 MPa. Since carbon dioxide becomes a supercritical fluid at a relatively low temperature, the cost of energy required for heating can be reduced. Further, when carbon dioxide is used as the supercritical fluid 1, it easily changes to a gas in the decompression step, so there is no need to provide a drying step for drying the produced resin-containing particles.

Further, in the heating and stirring step, in order to increase the dispersibility of the dispersant 3 described later and to improve the dispersibility of the raw material 7 of the resin-containing particles in the supercritical fluid 1, an assist in reducing the viscosity of the resin contained in the raw material 7 It is preferred to add solvent 2. An organic solvent can be used as the cosolvent 2 and is appropriately selected according to the type of supercritical fluid, the type of binder resin component, and the like. In particular, those that are not compatible with the resin contained in the raw material 7 under normal temperature and normal pressure (25 ° C., 1.013 × 10 ⁵ Pa) are preferable. If the cosolvent 2 is compatible with the resin, the produced resin-containing particles are softened, and there is a possibility that coarse particles are generated due to fusion of the particles.

  Specific examples of the organic solvent used for the co-solvent 2 include, for example, alcohols such as methanol, ethanol, isopropanol and butanol, ketones such as methyl ethyl ketone, acetone and cyclohexanone, ethers such as diethyl ether and tetrahydrofuran, toluene and benzene. And hydrocarbons such as cyclohexane, esters such as ethyl acetate, butyl acetate, methyl acetate and alkyl carboxylic acid esters, and halogenated hydrocarbons such as chlorobenzene and dichloromethane. Among these, lower alcohols are preferable from the viewpoint of suppressing the denaturation of the binder resin and reducing the burden on the environment, and among these, ethanol that is easy to handle is most preferably used.

  The cosolvent 2 is preferably supplied after being pressurized to a pressure higher than the critical pressure of the supercritical fluid 1. Further, the content of the cosolvent 2 is preferably 10 to 50% by weight, more preferably 20 to 30% by weight in the mixed fluid of the supercritical fluid 1 and the cosolvent 2. If the content of the cosolvent 2 is less than 10% by weight, the effect of softening the resin contained in the raw material 7 is not sufficiently exhibited. If the content of the cosolvent 2 exceeds 50% by weight, the resin contained in the raw material 7 may be too soft and cause fusion of particles.

  The dispersant 3 includes particles 4 that are insoluble in the supercritical fluid 1 (hereinafter referred to as supercritical insoluble particles) 4 and organic substances that are soluble in the supercritical fluid 1 (hereinafter referred to as supercritical soluble organic substances) 5. Is dispersed in the hydrophobic medium 6.

  Each of the supercritical insoluble particles 4 and the supercritical soluble organic substance 5 is used alone as a dispersant. When only one of these is used as a dispersant, the interparticle distance between the resin-containing particles produced can be stably maintained in the heating and stirring step, but the interparticle distance between the resin-containing particles can be maintained in the decompression step. It cannot be kept stable, and the resin-containing particles are fused.

  In the heating and stirring step, the crushed resin contained in the raw material 7 in the supercritical fluid 1 is softened by the mixed fluid of the supercritical fluid 1 and the cosolvent 2, and the surroundings are supercritical insoluble particles 4 or supercritically soluble. It is emulsified and atomized while surrounded by the organic matter 5. At this time, the generated resin-containing particles maintain a sufficient inter-particle distance due to the presence of the supercritical fluid 1 and the supercritical insoluble particles 4 or the supercritical soluble organic matter 5 even in a high-pressure environment. Is in a stable state. However, in the decompression step, for example, when carbon dioxide is used as the supercritical fluid 1, when the supercritical fluid 1 is decompressed and returned to normal pressure, the carbon dioxide returns to a gas, and the interparticle distance of the resin-containing particles is reduced. The interparticle distance of the contained particles cannot be stabilized. As a result, fusion between the resin-containing particles occurs, causing problems such as an increase in particle size and a wide particle size distribution.

  Therefore, as the dispersant 3 of the present invention, a dispersion in which supercritical insoluble particles 4 and supercritical soluble organic substances 5 are dispersed in a hydrophobic medium 6 is used.

  As the supercritical insoluble particles 4, it is preferable to use particles containing at least one selected from silicon dioxide, titanium dioxide and organic pigments. Examples of the organic pigment include carbon black, phthalocyanine, and quinacridone. Of these, silicon dioxide is particularly preferred. Such supercritical insoluble particles 4 have a sufficiently small primary particle diameter compared to the resin-containing particles to be produced, so that the dispersion ability of the resin in the supercritical fluid 1 is high, and the resin-containing particles are efficiently used. The diameter can be reduced well.

  In addition to these, the supercritical insoluble particles 4 include, for example, tin oxide, zinc oxide, aluminum oxide, strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, and other metal oxides such as silicon nitride. Carbides such as nitride and silicon carbide, fatty acid metal salts such as calcium sulfate, barium sulfate, calcium carbonate, zinc stearate, and calcium stearate may be used. These may be used alone or in combination. The particle size of the supercritical insoluble particles 4 is preferably about 10 to 600 nm.

  Furthermore, it is preferable that the surface of the supercritical insoluble particles 4 is previously hydrophobized. As the hydrophobizing agent used for the hydrophobizing treatment, for example, a silane coupling agent, silicone oil, titanate coupling agent, or the like can be used. The amount of the hydrophobizing agent used is 1 to 40 parts by weight, preferably 2 to 35 parts by weight, based on 100 parts by weight of the supercritical insoluble particles 4. For the hydrophobizing treatment, known and commonly used means can be used. By making the supercritical insoluble particles 4 hydrophobic, it is possible to exhibit higher dispersibility as the dispersant 3, and it is possible to narrow the particle size distribution of the resin-containing particles.

  The content of the supercritical insoluble particles 4 is not particularly limited, but is preferably included in the dispersant 3 by 5 to 10% by weight. If the content of the supercritical insoluble particles 4 is less than 5% by weight, the resin contained in the raw material 7 may not be sufficiently emulsified in the supercritical fluid 1. Moreover, when it exceeds 10 weight%, there exists a possibility that the physical property of the resin containing particle | grains manufactured may change.

  As the supercritically soluble organic substance 5, for example, a fluororesin, a silicone resin, a polyester resin, an acrylic resin, or the like, which is an organic substance having a weight average molecular weight of about several thousand to 10,000 can be used. These may be used alone or in combination. Among these, those containing at least one selected from a fluororesin, a silicone resin, and an acrylic resin are particularly preferable. These resins are easily dissolved in the supercritical fluid 1 and can further improve the dispersion ability as the dispersant 3.

  Although content of the supercritical soluble organic substance 5 is not specifically limited, It is preferable that it is 1 to 5 weight% in the dispersing agent 3, More preferably, it is 1.5 to 2.5 weight%. If the content of the supercritical soluble organic substance 5 is less than 1% by weight, the resin contained in the raw material 7 may not be sufficiently emulsified in the supercritical fluid 1. If the content of the supercritical soluble organic substance 5 exceeds 5% by weight, the storage stability as the powder performance may be deteriorated, for example, fusion of the resins contained in the raw material 7 may occur in the supercritical fluid 1. There is.

  Examples of the hydrophobic medium 6 contained in the dispersant 3 include aliphatic hydrocarbons such as n-pentane, n-hexane, n-octane, and cyclohexane, aromatic hydrocarbons such as ethylbenzene, xylene, and toluene, isobutyl acetate, and isopropyl acetate. And esters such as butyl acetate and ethyl acetate, and ketones such as methyl isopropyl ketone, methyl propyl ketone, and methyl ethyl ketone. Commercially available aliphatic hydrocarbons can also be used. Examples of commercially available aliphatic hydrocarbons include Isopar (registered trademark) E. Among these, n-hexane, Isopar E and the like that do not dissolve the resin contained in the raw material 7 are preferable.

  When the hydrophobic solvent 6 that does not dissolve the resin contained in the raw material 7 is used, the surface area is not reduced by the fusion of the resins contained in the raw material 7 in the heating and stirring step. Therefore, the contact area between the dispersant 3 and the resin Also, the effect of the dispersant 3 can be sufficiently exhibited. Therefore, for example, when carbon dioxide is used as the supercritical fluid 1, the supercritical fluid 1 is decompressed in the decompression step so that the carbon dioxide returns to the gas, and even if the interparticle distance between the resin-containing particles decreases, The contact area with the resin-containing particles is not reduced, and the effect of the dispersant 3 can be sufficiently exerted, and the particles can be prevented from being fused with each other. Can be narrowed.

  Even if a hydrophobic medium that dissolves the resin contained in the raw material 7 is used as the hydrophobic medium 6, granulation is possible if the amount of the dispersant used is small. However, when a hydrophobic medium that dissolves such a resin is used, the particles are fused with each other, making it difficult to reduce the diameter of the resin-containing particles, which may widen the particle size distribution.

  Therefore, preferably, when the supercritical insoluble particles 4 and the supercritical soluble organic matter 5 are dispersed in the hydrophobic medium 6 that does not dissolve the resin, the supercritical soluble organic matter 5 is optimally oriented with respect to the supercritical insoluble particles 4. Since the ability to emulsify the resin contained in the raw material 7 in the supercritical fluid 1 becomes higher than when each is used alone, the resin-containing particles can be made smaller in diameter and the particle size can be reduced. The distribution can be narrowed. The content of the hydrophobic medium 6 in the dispersant 3 is the remainder of the content of the supercritical insoluble particles 4 and the supercritical soluble organic matter 5 in the dispersant 3.

  The dispersant 3 is prepared by mixing the supercritical insoluble particles 4 and the supercritically soluble organic matter 5 as described above in a hydrophobic medium 6 using, for example, a bead mill such as a sand grinder disperser (manufactured by Taihei System Co., Ltd.). It is obtained by dispersing for about time and pre-processing. The dispersing agent 3 used in the production method of the present invention comprises a supercritical insoluble particle 4 and a supercritical soluble organic substance 5 in order to obtain an optimal orientation state of the supercritical insoluble particle 4 and the supercritical soluble organic substance 5. It is characterized by not only mixing in the hydrophobic medium 6 but also a pretreatment for dispersing both in the hydrophobic medium 6 as described above.

  The supercritical insoluble particles 4 and the supercritically soluble organic matter 5 are preferably mixed in a ratio of about 2: 1 to 3: 1, although it depends on the particle size or surface area of the supercritical insoluble particles 4. If the supercritically soluble organic substance 5 is too small, a sufficient steric hindrance effect cannot be obtained, and as a result, the dispersibility of the resin contained in the raw material 7 may be inferior. Moreover, when there is too much quantity of the supercritically soluble organic substance 5, since there exists a possibility that the produced resin containing particle | grains may melt | fuse, it is unpreferable.

  Further, the sum of the contents (solid content concentration) of the supercritical insoluble particles 4 and the supercritical soluble organic matter 5 which are solid contents in the dispersant 3 is preferably 5 to 15% by weight, more preferably 7 to 10%. % By weight. If the solid content concentration is less than 5% by weight, the number of times of contact between the supercritical insoluble particles 4 and the supercritical soluble organic substance 5 is reduced even if mixing is performed by a bead mill, and efficient mixing may not be performed. When the solid content concentration exceeds 15% by weight, the viscosity of the dispersing agent 3 itself becomes high and gelation may occur, and it may not be uniformly mixed in the supercritical fluid 1.

  As described above, the supercritical insoluble particles 4 and the supercritical soluble organic substance 5 contained in the dispersant 3 can be used alone to emulsify the resin contained in the raw material 7 in the supercritical fluid 1, Although the contained particles can be atomized, by dispersing them in the hydrophobic medium 6, the supercritical soluble organic substance 5 becomes in an optimal orientation state with respect to the particles that are insoluble in the supercritical fluid 1, and Since it is possible to prevent fusion of the resins present in the critical fluid 1 in an emulsified state, the generation of coarse particles can be further prevented, and the particle size distribution of the resin-containing particles can be narrowed.

  The amount of the dispersant 3 added to the supercritical fluid 1 is preferably 100 parts by weight or more and 250 parts by weight or less, and more preferably 100 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the resin contained in the raw material 7. It is. If the added amount of the dispersant 3 is less than 100 parts by weight, the resin may not be sufficiently dispersed in the supercritical fluid 1. When the addition amount of the dispersant 3 exceeds 250 parts by weight, the influence of the dispersant 3 on the physical properties of the resin-containing particles becomes large.

  The resin contained in the raw material 7 of the method for producing resin-containing particles of the present invention is not particularly limited as long as it is thermoplastic and insoluble in the supercritical fluid 1. Examples of such resins include styrene resins such as polystyrene, styrene-butadiene copolymer, styrene-acrylic copolymer, ethylene such as polyethylene, polyethylene-vinyl acetate copolymer, polyethylene-vinyl alcohol copolymer. Examples thereof include acrylic resins, acrylic resins such as polymethyl methacrylate, phenolic resins, epoxy resins, allyl phthalate resins, polyamide resins, polyester resins, polyether resins, and maleic resins. These resins may be used alone or in combination.

  The raw material 7 may contain pigments, waxes, and the like. In this way, resin-containing particles with a small particle size distribution and narrow particle size distribution can be produced using raw materials including not only resins but also pigments, waxes, etc., making it suitable for a wide range of fields such as toner for electrophotography. Possible resin-containing particles can be produced.

  As the pigment used for such a raw material 7, known inorganic or organic pigments can be used. For example, carbon black, aniline black, acetylene black, naphthol yellow, Hansa yellow, rhodamine lake, alizarin lake, Bengala, Examples include phthalocyanine blue and indanthrene blue. These are usually used in an amount of 0.5 to 20 parts by weight per 100 parts by weight of the resin contained in the raw material 7.

  As the wax used for the raw material 7, known waxes can be used, such as synthetic waxes such as polyethylene, polypropylene, ethylene-propylene copolymer, polyolefin, vegetable waxes such as carnauba wax, jojoba oil, rice wax, and montan. Examples thereof include a wax containing at least one selected from mineral waxes such as wax. The wax is preferably contained in an amount of 2 to 8 parts by weight with respect to 100 parts by weight of the resin contained in the raw material 7.

  The raw material 7 may contain not only a resin, a pigment and a wax, but also an additive such as a charge control agent as long as preferable characteristics are not impaired. Thus, in the case of using a raw material containing a resin and a component other than the resin, after preliminarily mixing with a high-speed stirring type mixing device such as a super mixer or a Henschel mixer, a twin-screw extruder, a three-roll, a lab blast It is preferable that melt kneading is performed by a general kneader such as a mill.

  By introducing the raw material 7 as described above, the dispersant 3, and preferably the co-solvent 2 into the supercritical fluid 1 and stirring while heating so that the supercritical fluid 1 does not vaporize or liquefy, The raw material 7 particles containing resin are dispersed in the critical fluid 1. When the particles of the raw material 7 are dispersed in the supercritical fluid 1, it is then subjected to a decompression step.

  In the depressurization step, the supercritical fluid 1 is vaporized or liquefied by reducing the pressure of the supercritical fluid 1, and the raw material 7 particles dispersed in the supercritical fluid 1, that is, resin-containing particles constitute the supercritical fluid 1. Separated from the substance fluid. Here, when carbon dioxide is used as the supercritical fluid 1, since carbon dioxide is vaporized by decompression, there is no need to separate the resin-containing particles from the fluid constituting the supercritical fluid 1, and the resin-containing particles are dried. This is preferable because it does not need to be performed. When a substance that liquefies in a decompression step is used as the substance constituting the supercritical fluid 1, a separation process between the resin-containing particles and the liquid constituting the supercritical fluid 1, a washing process for the resin-containing particles, and a drying process for the resin-containing particles Etc. as necessary.

  FIG. 2 is a system diagram schematically showing a resin-containing particle production apparatus 11 that is preferably used in the method for producing resin-containing particles of the present invention. The resin-containing particle manufacturing apparatus 11 includes a thermometer 12, a pressure gauge 13, a heater 14, a stirring means 16, a supercritical fluid 1, and a resin that is a raw material for the resin-containing particles in the supercritical fluid 1. A reaction vessel 17 for dispersing the containing raw material 7, a gas cylinder 18 for supplying the raw gas of the supercritical fluid 1 to the reaction vessel 17, and an additive for pressurizing the raw gas of the supercritical fluid 1 supplied from the gas cylinder 18. A pressure pump 19, a source gas supply valve 20 for adjusting the flow rate of the pressurized source gas supplied from the pressurizing pump 19, a tank 21 filled with the cosolvent 2, and a cosolvent supplied from the tank 21 A pressure pump 22 for pressurizing 2, a co-solvent supply valve 23 for controlling the amount of pressurized co-solvent 2 supplied from the pressure pump 22 to the reaction vessel 17, and a pressure reducing valve 15 of A pipe for allowing the dispersion of the raw material 7 discharged from the reaction vessel 17 to flow by being discharged, a dispersion supply pipe 24 provided with a pressure reducing valve 15 in the middle, and a heater 25 provided on the outer periphery of the dispersion supply pipe 24. A nozzle 26 for discharging resin-containing particles generated from the dispersion, a nozzle heater 27 provided on the outer periphery of the nozzle 26, and a nozzle 26. And a particle collecting container 28 for collecting the resin-containing particles released from 26.

  The raw material gas is supplied from the gas cylinder 18 to the pressurizing pump 19, pressurized by the pressurizing pump 19, and then supplied to the reaction vessel 17 through the raw material gas supply valve 20. As the source gas, carbon dioxide having a critical temperature close to room temperature and a small environmental load is particularly preferably used.

  The co-solvent 2 filled in the tank 21 is supplied to the pressurization pump 22, pressurized by the pressurization pump 22, and then supplied to the reaction vessel 17 through the co-solvent supply valve 23.

  The reaction vessel 17 includes a thermometer 12 for measuring the temperature in the reaction vessel 17, a pressure gauge 13 for measuring the pressure in the reaction vessel 17, a heater 14 for heating the contents of the reaction vessel 17, and the contents of the reaction vessel 17. Is provided, and one end of the dispersion supply pipe 24 is connected. The stirring means 16 is composed of, for example, a wing-shaped stirring member and a motor, and the contents of the reaction vessel 17 are stirred by rotating the stirring member by the motor.

  The reaction vessel 17 is charged with appropriate amounts of the raw material 7 containing at least the resin and the dispersant 3 in which the supercritical fluid insoluble particles 4 and the supercritical fluid soluble organic substance 5 are dispersed in the hydrophobic medium 6. The Furthermore, appropriate amounts of the pressurized source gas and auxiliary solvent 2 are supplied via the raw material gas supply valve 20 and the auxiliary solvent supply valve 23. At this time, the pressure reducing valve 15 is closed. The temperature and pressure in the reaction vessel 17 are measured by the thermometer 12 and the pressure gauge 13, respectively, and adjusted by the heater 14 and the pressurizing pump 19. When an appropriate amount of source gas and auxiliary solvent 2 are supplied and a desired pressure is obtained, the source gas supply valve 20 and auxiliary solvent supply valve 23 are closed to stop supply. When the desired temperature and pressure are obtained in this way, the supercritical fluid 1 is generated from the raw material gas, and the raw material 7 and the dispersant 3 are stirred in the supercritical fluid 1 by the rotation of the stirring member by the motor, and uniformly scatter. In this way, a uniform dispersion system is formed in the reaction vessel 17, and this state is maintained for a certain time.

  Next, the decompression valve 15 is opened, the supercritical fluid in the reaction vessel 17 is discharged by the decompression valve 15, and the pressure is reduced to near atmospheric pressure to vaporize. At this time, the resin-containing particles made of the raw material 7 dispersed in the supercritical fluid 1 are separated.

  The dispersion supply pipe 24 connected to the reaction vessel 17 via the pressure reducing valve 15 is connected to the raw material gas generated from the supercritical fluid 1 and the supercritical fluid formed from the raw material 7 by reducing the pressure simultaneously with opening of the pressure reducing valve 15. A mixture of the resin-containing particles separated from 1, the cosolvent 2, and the dispersant 3 is fed. Most of the cosolvent 2 in the mixture and the hydrophobic medium 6 in the dispersant 3 are vaporized by heating with the heater 25 and the nozzle heater 27. The mixture that has flowed through the dispersion supply pipe 24 is discharged from the nozzle 26 as an air stream containing resin-containing particles into the particle collection container 28, and the resin-containing particles are collected in the particle collection container 28.

  Even if the cosolvent 2 and the dispersant 3 are attached to the resin-containing particles discharged from the nozzle 26, if the cosolvent 2 and the hydrophobic medium 6 that are incompatible with the resin contained in the raw material 7 are used, Resin-containing particles do not adhere to each other, and resin-containing particles in a fine state can be obtained. Moreover, the cosolvent 2 and the hydrophobic medium 6 adhering to the resin-containing particles are vaporized and removed by the residual heat. Although the supercritical insoluble particles 4 and the supercritical soluble particles 5 contained in the dispersant 3 adhere to the resin-containing particles, since they are very small amounts, the physical properties of the resin-containing particles are hardly affected.

  Such a resin-containing particle manufacturing apparatus 11 is not limited to the above configuration, and various modifications can be made.

  For example, heating means such as a heater or a coil (not shown) is provided between the pressurization pump 19 and the source gas supply valve 20 and / or between the pressurization pump 22 and the auxiliary solvent supply valve 23 to pressurize the source material. The gas and / or the cosolvent 2 may be heated to a temperature close to a desired temperature. Further, a mixing container (not shown) may be provided between the pressure pumps 19 and 12 and the reaction container 17 so that the raw material gas and the cosolvent are mixed and then supplied to the reaction container 17.

  Furthermore, a thermostat (not shown) or the like can be used in place of the heater 14 provided outside the reaction vessel 17. Further, a thermometer (not shown) may be installed near the outlet of the nozzle 26 to measure the outlet temperature, and the vaporization status of the cosolvent 2 may be examined.

  According to the method for producing resin-containing particles of the present invention, by using the hydrophobic medium 6 in which the supercritical insoluble particles 4 and the supercritical soluble organic matter 5 are dispersed as the dispersant 3, the supercritical soluble organic matter 5 is obtained. The resin in the supercritical fluid 1 can be surrounded and dispersed in an optimally oriented state with respect to the supercritical insoluble particles 4. This dispersing agent 3 is used to reduce the supercritical fluid 1, for example, carbon dioxide, to a gas and return the gas to the gas. Even if the interparticle distance between the resin-containing particles is reduced in the cosolvent 2, the supercritical insoluble particles 4 or supercritical Since the steric hindrance is larger than that of the dispersant using each of the dissolved organic substances 5 alone, the distance between the produced resin-containing particles can be stably maintained, so that the fusion of the particles can be prevented. Therefore, resin-containing particles having a small particle size and a narrow particle size distribution can be obtained.

  Examples of the present invention will be described below. The dispersant used for the production of the resin-containing particles of Examples and Comparative Examples was prepared as follows.

[Dispersant A]
10 parts by weight of hydrophobic titanium dioxide (AEROSIL T805; manufactured by Nippon Aerosil Co., Ltd.) as supercritical insoluble particles, and 5 parts by weight of acrylic resin (EFKA-4400; manufactured by Efcar Chemicals) as supercritical soluble organic substances are used. It was dispersed in 185 parts by weight of Isopar E (Esso Standard Petroleum), which is a hydrophobic medium, together with 300 parts by weight of beads using a sand grinder disperser (manufactured by Taihei System Co., Ltd.) for 1 hour. Dispersant A was obtained by removing the beads after dispersion.

[Dispersant B]
Dispersant B was prepared in the same manner as Dispersant A, except that no supercritically soluble organic acrylic resin was used and that the mixture was lightly mixed by hand stirring without using a sand grinder disperser.

[Dispersant C]
Dispersant C was prepared in the same manner as Dispersant A, except that the supercritical insoluble particles of hydrophobic titanium dioxide were removed, and the mixture was lightly mixed by hand stirring without being dispersed by a sand grinder disperser.

[Dispersant D]
Dispersant D was prepared in the same manner as Dispersant A, except that the mixture was lightly mixed by hand stirring without dispersing with a sand grinder disperser.

[Dispersant E]
Dispersant E was prepared in the same manner as Dispersant A, except that toluene was used as the hydrophobic medium.

[Dispersant F]
Dispersant F was produced in the same manner as Dispersant A, except that ethanol, which is a hydrophilic medium, was used instead of the hydrophobic medium.

[Dispersant G]
Dispersant G was prepared in the same manner as Dispersant A, except that n-hexane was used as the hydrophobic medium.

[Dispersant H]
Dispersant H was prepared in the same manner as Dispersant G, except that hydrophobic silicon dioxide (AEROSIL RX2000; manufactured by Nippon Aerosil Co., Ltd.) was used as supercritical insoluble particles.

[Dispersant I]
Dispersant I was prepared in the same manner as Dispersant G, except that a cyan pigment (Fastogen Blue RG; manufactured by Dainippon Ink & Chemicals, Inc.) was used as supercritical insoluble particles.

[Dispersant J]
Dispersant J was prepared in the same manner as Dispersant H, except that untreated silicon dioxide (AEROSIL OX50; manufactured by Nippon Aerosil Co., Ltd.) was used as supercritical insoluble particles.

[Dispersant K]
Dispersant K was prepared in the same manner as Dispersant H, except that a silicone resin (EMALEX SS-5050K; manufactured by Nippon Emulsion Co., Ltd.) was used as the supercritical soluble organic substance.

[Dispersant L]
Dispersant L was produced in the same manner as Dispersant H, except that a fluororesin (Furgent 300; manufactured by Neos Co., Ltd.) was used as the supercritical soluble organic substance.

[Dispersant M]
Dispersant M was prepared in the same manner as Dispersant H, except that urethane resin (EFKA-4047; manufactured by Efcar Chemicals) was used as the supercritical soluble organic substance.

  Table 1 summarizes the supercritical insoluble particles, supercritical soluble organic substances, hydrophobic or hydrophilic media used for the preparation of the dispersants A to M, and the preparation methods of the respective dispersants.

  Using the dispersants A to M produced as described above, resin-containing particles of Examples and Comparative Examples were produced as follows.

<Example 1>
Using the resin-containing particle manufacturing apparatus 11 shown in FIG. 2, the resin-containing particles of Example 1 were manufactured as follows. The volume of the reaction vessel 17 of the resin-containing particle production apparatus 11 was 1000 ml.

  100 g of polyester resin (EP208; manufactured by Sanyo Chemical Industries, Ltd .; melting point 117 ° C.) as a raw material and 100 g of dispersant A as a dispersing agent were charged into the reaction vessel, and the temperature in the reaction vessel was set to 50 ° C. and sealed. . Moreover, 300 g of ethanol was supplied to the reaction vessel as a cosolvent. While stirring the contents of the reaction vessel at 1500 rpm by the stirring means, carbon dioxide pressurized by a pressure pump was supplied until the pressure in the reaction vessel reached 20 MPa. Thus, a supercritical fluid of carbon dioxide was generated in the reaction vessel, the temperature in the reaction vessel was changed to 40 ° C., and the pressure in the reaction vessel was 25 MPa. Thereafter, the stirring speed was increased to 3000 rpm and stirring was performed for about 3 hours to disperse the polyester resin in the supercritical fluid. Thereafter, the pressure reducing valve was opened, and the particles deposited in the particle collecting container were collected to obtain resin-containing particles.

<Comparative example 1>
Resin-containing particles of Comparative Example 1 were produced in the same manner as in Example 1 except that the dispersant was changed to Dispersant B.

<Comparative example 2>
Resin-containing particles of Comparative Example 2 were produced in the same manner as in Example 1 except that the dispersant was changed to Dispersant C.

<Comparative Example 3>
Resin-containing particles of Comparative Example 3 were produced in the same manner as in Example 1 except that the dispersant was changed to Dispersant D.

<Example 2>
Resin-containing particles of Example 2 were produced in the same manner as in Example 1 except that the dispersant was changed to Dispersant E.

<Comparative example 4>
Resin-containing particles of Comparative Example 4 were produced in the same manner as in Example 1 except that the dispersant was changed to Dispersant F.

<Example 3>
Resin-containing particles of Example 3 were produced in the same manner as in Example 1 except that the dispersant was changed to Dispersant G.

<Example 4>
Resin-containing particles of Example 4 were produced in the same manner as Example 1 except that the dispersant was changed to Dispersant H.

<Example 5>
Resin-containing particles of Example 5 were produced in the same manner as Example 1 except that the dispersant was changed to Dispersant I.

<Example 6>
Resin-containing particles of Example 6 were produced in the same manner as Example 1 except that the dispersant was changed to Dispersant J.

<Example 7>
Resin-containing particles of Example 7 were produced in the same manner as in Example 1 except that the dispersant was changed to Dispersant K.

<Example 8>
Resin-containing particles of Example 8 were produced in the same manner as in Example 1 except that the dispersant was changed to Dispersant L.

<Example 9>
Resin-containing particles of Example 9 were produced in the same manner as Example 1 except that the dispersant was changed to Dispersant M.

<Example 10>
Resin-containing particles of Example 10 were produced in the same manner as in Example 4 except that the raw material was changed to the resin kneaded material A produced as follows.

[Resin kneaded product A]
380 parts by weight of a polyester resin (EP208; manufactured by Sanyo Chemical Industries Co., Ltd.) and 20 parts by weight of a phthalocyanine pigment (Fastogen Blue 5415; manufactured by Dainippon Ink & Chemicals) are charged into a Henschel mixer and mixed for 10 minutes. A cyan resin kneaded product A was produced by melt-kneading at a temperature of 130 ° C. or less with Kneedic (MOS140-800; manufactured by Mitsui Mining Co., Ltd.).

<Example 11>
Resin-containing particles of Example 11 were produced in the same manner as in Example 4 except that the raw material was changed to the resin kneaded material B produced as follows.

[Resin kneaded product B]
356 parts by weight of a polyester resin (EP208; manufactured by Sanyo Chemical Industries), 20 parts by weight of a phthalocyanine pigment (Fastogen Blue 5415; manufactured by Dainippon Ink & Chemicals) and a polywax (polywax 850; manufactured by Toyo Petrolite Co., Ltd.) 24 parts by weight were mixed and melt-kneaded in the same manner as in the resin kneaded product A described above to prepare a cyan resin kneaded product B.

  The volume average particle size of the resin-containing particles of Examples and Comparative Examples obtained as described above was measured, and the particle size distribution and the generation amount of coarse particles were evaluated.

(Measurement of volume average particle diameter)
The particle size of the resin-containing particles was measured with a laser diffraction particle size measuring device (Horiba, Ltd .: LA-920), and the volume average particle size was calculated from the value.

(Evaluation of particle size distribution)
Based on the measured value of the volume average particle size and the standard deviation thereof, the particle size distribution of the resin-containing particles of Examples and Comparative Examples was evaluated by the coefficient of variation calculated from the following formula (1). The evaluation criteria were ◯ when the variation coefficient was 30 or less, and x when the variation coefficient exceeded 30.
Coefficient of variation = standard deviation / volume average particle diameter (1)

(Evaluation of the amount of coarse particles generated)
It was evaluated whether coarse particles were generated in the resin-containing particles of Examples and Comparative Examples. The generation amount of coarse particles was evaluated as “◯” when no generation occurred, “Δ” when generation occurred in a range of less than 5% by weight of the raw material, and “X” generated in the range of 5% by weight or more of the raw material.

    Table 2 shows the volume average particle diameters of the resin-containing particles of Examples and Comparative Examples, and the evaluation results of the particle size distribution and the amount of coarse particles generated.

  From Table 2, the resin-containing particles produced by the production method of the present invention had a volume average particle size as small as 10 μm or less, a narrow particle size distribution, and no coarse particles were generated. In particular, when Isopar E that does not dissolve the resin is used as the hydrophobic medium (Example 1), and when n-hexane that is highly hydrophobic and does not dissolve the resin is used (Example 3), the particle size is further reduced. Thus, resin-containing particles having a narrow particle size distribution could be produced.

  Moreover, when hydrophobized silicon dioxide was used as supercritical insoluble particles (Example 4), the generation of coarse particles was significantly suppressed, and the particle size distribution could be narrowed. When acrylic resin, silicone resin and fluororesin were used as supercritically soluble organic substances (Examples 7 and 8), resin-containing particles having a narrower particle size distribution could be produced.

  Furthermore, even when a material containing a pigment, wax or the like was used as a raw material (Examples 10 and 11), resin-containing particles having a narrow particle size distribution and a small particle size could be produced. It can be seen that the particle manufacturing method can be applied to a wide range of fields such as electrophotographic toner.

  On the other hand, when only a supercritical insoluble particle or a supercritically soluble organic substance as a dispersant is mixed with a hydrophobic medium (Comparative Examples 1 and 2), a large number of coarse particles are generated and the particle size distribution is widened. The particle size of the resulting particles was also large. In addition, in the case of using a dispersant that contains both supercritical insoluble particles and supercritically soluble organic matter but is mixed only in the hydrophobic medium but not dispersed (Comparative Example 3), hydrophilicity is used instead of the hydrophobic medium. The same result was obtained when ethanol (a comparative medium) was used (Comparative Example 4).

It is a figure explaining the manufacturing method of the resin containing particle | grains which is 1 aspect of implementation of this invention. It is a systematic diagram which simplifies and shows the resin containing particle manufacturing apparatus 11 used suitably for the manufacturing method of the resin containing particle | grains of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Supercritical fluid 2 Cosolvent 3 Dispersant 4 Supercritical insoluble particle 5 Supercritical soluble organic substance 6 Hydrophobic medium 7 Raw material 8,17 Reaction vessel 11 Resin-containing particle production apparatus 12 Thermometer 13 Pressure gauge 14, 25 Heater 15 Depressurization Valve 16 Stirring means 18 Gas cylinder 19 Pressure pump 20 Raw material gas supply valve 21 Tank 22 Pressure pump 23 Cosolvent supply valve 24 Dispersion supply pipe 26 Nozzle 27 Nozzle heater 28 Particle collection container

Claims (8)

Introducing a raw material containing at least a resin and a dispersing agent for dispersing the raw material in the supercritical fluid or subcritical fluid into the supercritical fluid or subcritical fluid and stirring them while heating; Reducing the pressure of the critical fluid, and a method for producing resin-containing particles,
The dispersant is
A method for producing resin-containing particles, characterized in that particles that are insoluble in a supercritical fluid or subcritical fluid and organic substances that are soluble in the supercritical fluid or subcritical fluid are dispersed in a hydrophobic medium. . The hydrophobic medium is
The method for producing resin-containing particles according to claim 1, wherein the resin contained in the raw material is not dissolved. Particles that are insoluble in supercritical or subcritical fluids
The method for producing resin-containing particles according to claim 1, comprising at least one selected from silicon dioxide, titanium dioxide, and organic pigments. Particles that are insoluble in supercritical or subcritical fluids
The method for producing resin-containing particles according to any one of claims 1 to 3, wherein the surface is hydrophobized in advance. Organic substances that are soluble in supercritical or subcritical fluids
The method for producing resin-containing particles according to any one of claims 1 to 4, comprising one or more selected from a fluororesin, a silicone resin, and an acrylic resin. Supercritical fluid or subcritical fluid is
It is a carbon dioxide, The manufacturing method of the resin containing particle | grains as described in any one of Claims 1-5 characterized by the above-mentioned. The raw material is
The method for producing resin-containing particles according to claim 1, comprising a pigment and a wax. An electrophotographic toner produced by the method for producing resin-containing particles according to claim 1.

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