Method for producing resin particle dispersion liquid, method for producing toner for electrostatic charge image development, and toner for electrostatic charge image development

Abstract

To provide a method for producing a resin particle dispersion which suppresses reduction in a yield rate which is caused by the adherence of a resin onto an inner wall surface of a distillation tank.SOLUTION: There is provided a method for producing a resin particle dispersion which comprises a step of preparing a phase inversion emulsified liquid obtained by subjecting a resin to phase inversion emulsification using an organic solvent and an aqueous medium and a step of removing the organic solvent from the phase inversion emulsified liquid by vacuum distillation, wherein the vacuum distillation is performed and an aqueous medium is added to the phase inversion emulsified liquid stored in the distillation tank during the vacuum distillation using a vacuum distillation apparatus equipped with one or plurality of a gutter-shaped stirring blades which are mounted on an agitation shaft, stir the phase inversion emulsified liquid by rotation and scoop up the phase inversion emulsified liquid and form a liquid film of the phase inversion emulsified liquid on a heat transfer surface of the distillation tank above the liquid surface of the phase inversion emulsified liquid.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for producing a resin particle dispersion liquid, a method for producing a toner for electrostatic charge image development, and a toner for electrostatic charge image development.

Background Art

[0002] For example, Patent Document 1 discloses "a water dispersion production apparatus comprising a water dispersion production tank for producing a water dispersion, a retained liquid composition detection means for detecting the composition of a retained liquid recovered in the process of desolventizing from the water dispersion production tank, at least two or more retained liquid recovery tanks for separating and recovering the retained liquid according to the retained liquid composition, and a supply means for supplying the retained liquid stored in at least one of the retained liquid recovery tanks to the water dispersion production tank."

[0003] Further, Patent Document 2 discloses "a method for producing toner base particles, comprising a step of dissolving or dispersing a toner material containing at least a binder resin and / or a binder resin precursor, a colorant, and a release agent in an organic solvent to prepare a first liquid; a step of emulsifying or dispersing the first liquid in an aqueous medium to prepare a second liquid having a viscosity of 50 mPa·s or more and 800 mPa·s or less as measured using a Brookfield viscometer at a rotational speed of 60 rpm and a temperature of 25°C; and a step of volatilizing the organic solvent by a heating unit that heats the second liquid flowing as a liquid film substantially vertically downward along the inner wall surface of a pipe whose pressure is reduced to 70 kPa or less while maintaining the temperature of the second liquid flowing as the liquid film below the glass transition point of the toner base particles through the wall surface of the pipe, wherein a lower end portion of the pipe through which the liquid film flows protrudes from the heating unit."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 1

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventionally, a resin particle dispersion is known to be produced by removing an organic solvent from a phase inversion emulsion by vacuum distillation. As an apparatus for performing vacuum distillation, there is "a vacuum distillation apparatus comprising a distillation tank for accommodating a phase inversion emulsion, a heating unit for flowing a heating fluid therein to heat the tank wall of the distillation tank, and a stirring unit provided in the distillation tank, the stirring unit having a stirring shaft and one or more gutter-shaped stirring blades attached to the stirring shaft and configured to stir the phase inversion emulsion by rotation and lift the phase inversion emulsion to form a liquid film of the phase inversion emulsion on the heat transfer surface of the distillation tank above the liquid level of the phase inversion emulsion (hereinafter, also referred to as a "specific vacuum distillation apparatus")."

[0006] An object of the present invention is to provide a method for producing a resin particle dispersion having a step of preparing a phase inversion emulsion obtained by phase inverting a resin using an organic solvent and an aqueous medium, and a step of removing the organic solvent from the phase inversion emulsion by vacuum distillation using a specific vacuum distillation apparatus, which suppresses a decrease in the yield due to the adhesion of the resin to the inner wall surface of the distillation tank as compared with the case where an aqueous medium is not added to the phase inversion emulsion accommodated in the distillation tank of the specific vacuum distillation apparatus during vacuum distillation.

Means for Solving the Problems

[0007] Specific means for solving the above problems include the following aspects. <1> A step of preparing a phase inversion emulsion obtained by phase inverting a resin using an organic solvent and an aqueous medium, A step of removing the organic solvent from the phase inversion emulsion by vacuum distillation, having a distillation tank for accommodating the phase inversion emulsion, a heating unit for flowing a heating fluid therein to heat the tank wall of the distillation tank, A stirring section provided in the distillation tank, comprising a stirring shaft and one or more gutter-shaped stirring blades attached to the stirring shaft, which stir the phase-inverted emulsion by rotation, lift the phase-inverted emulsion, and form a liquid film of the phase-inverted emulsion on the heat transfer surface of the distillation tank above the liquid level of the phase-inverted emulsion. Perform the vacuum distillation using a vacuum distillation apparatus comprising and add an aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation. A method for producing a resin particle dispersion. <2> The method for producing a resin particle dispersion according to <1>, wherein the relationship between the installation angle θ [°] of the gutter-shaped stirring blade with respect to the stirring shaft, the rotational speed N [rpm] of the stirring shaft, the inner diameter D [m] of the distillation tank, and the maximum diameter d [m] of the rotation locus of the gutter-shaped stirring blade satisfies the following formulas 1 to 4. Formula 1: 10 ≦ θ ≦ 45 Formula 2: 14 ≦ N·sinθ ≦ 60 Formula 3: 0.4 ≦ D ≦ 5 Formula 4: 0.75 ≦ d / D ≦ 0.95 <3> The method for producing a resin particle dispersion according to <1> or <2>, wherein the aqueous medium is added to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation so as to maintain the solid content concentration of the phase-inverted emulsion in the range of 25% by mass to 45% by mass. <4> The method for producing a resin particle dispersion according to any one of <1> to <3>, wherein the aqueous medium is added to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation so as to maintain the maximum viscosity of the phase-inverted emulsion in the range of 30 mPa·sec or less. <5> The distillation recovery rate per unit heat transfer surface of the distillation tank when adding the aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation is 60 kg / h / m 2 or less. The method for producing a resin particle dispersion according to any one of <1> to <4>. <6> When adding the aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation, the temperature T1 of the phase-inverted emulsion is 25°C or higher (the glass transition temperature Tg of the resin - 1°C) or lower, the temperature T2 of the heating fluid flowing inside the heating unit is 95°C or lower, and the relationship between T1 and T2 is T1 < T2. The method for producing a resin particle dispersion according to any one of <1> to <5>. <7> When adding the aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation, the temperature T3 of the aqueous medium is (the glass transition temperature Tg of the resin - 1°C) or lower. The method for producing a resin particle dispersion according to any one of <1> to <6>. <8> The temperature T3 of the aqueous medium is (the glass transition temperature Tg of the resin - 30°C) or higher and (the glass transition temperature Tg of the resin - 1°C) or lower, and is 5°C or higher. The method for producing a resin particle dispersion according to <7>. <9> When adding the aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation, the addition rate of the aqueous medium is an addition rate that varies within the range of the temperature T1 ± 5 of the phase-inverted emulsion when adding the aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation. The method for producing a resin particle dispersion according to any one of <1> to <8>. <10> Producing the phase-inverted emulsion in an emulsification tank, transferring it from the emulsification tank to the distillation tank, and performing the vacuum distillation. The method for producing a resin particle dispersion according to any one of <1> to <9>. <11> The resin is a resin having a polar group. The method for producing a resin particle dispersion according to any one of <1> to <10>. <12> The resin having a polar group is a resin having an acid value. The method for producing a resin particle dispersion according to <11>. <13> The content of the residual organic solvent in the resin particle dispersion is 25 ppm or higher and 3000 ppm or lower. The method for producing a resin particle dispersion according to any one of <1> to <2>. <14> The method for producing a resin particle dispersion liquid according to any one of <1> to <13> for producing a toner resin particle dispersion liquid. <15> In a dispersion liquid containing resin particles obtained by the method for producing a resin particle dispersion liquid according to any one of <1> to <14>, at least the resin particles are aggregated to form aggregated particles, and the step of forming aggregated particles; Heating the aggregated particle dispersion liquid in which the aggregated particles are dispersed, fusing and unifying the aggregated particles to form toner particles, and the step of forming toner particles; A method for producing an electrostatic charge image developing toner having. <16> An electrostatic charge image developing toner having toner particles obtained by the method for producing an electrostatic charge image developing toner according to <15>.

Effect of the Invention

[0008] According to the invention according to <1> or <14>, in the method for producing a resin particle dispersion liquid having a step of preparing a phase inversion emulsion in which a resin is phase-inverted and emulsified using an organic solvent and an aqueous medium, and a step of removing the organic solvent from the phase inversion emulsion by vacuum distillation using a specific vacuum distillation apparatus, during the vacuum distillation, compared with the case where an aqueous medium is not added to the phase inversion emulsion accommodated in the distillation tank of the specific vacuum distillation apparatus, a method for producing a resin particle dispersion liquid that suppresses a decrease in the yield due to the adhesion of the resin to the inner wall surface of the distillation tank is provided.

[0009] According to the invention according to <2>, compared with the case where the relationship between the installation angle θ [°] of the trough-shaped stirring blade with respect to the stirring shaft, the rotational speed N [rpm] of the stirring shaft, the inner diameter D [m] of the distillation tank, and the maximum diameter d [m] of the rotational locus of the trough-shaped stirring blade does not satisfy the following formulas 1 to 4, a method for producing a resin particle dispersion liquid that suppresses a decrease in the yield due to the adhesion of the resin to the inner wall surface of the distillation tank is provided.

[0010] According to the invention according to <3>, compared with the case where the solid content concentration of the phase inversion emulsion exceeds 45% by mass during the vacuum distillation, a method for producing a resin particle dispersion liquid that suppresses a decrease in the yield due to the adhesion of the resin to the inner wall surface of the distillation tank is provided.

[0011] According to the invention according to <4>, a method for producing a resin particle dispersion liquid is provided, which suppresses a decrease in yield due to adhesion of resin to the inner wall surface of a distillation tank, as compared with a case where the maximum viscosity of an inverse phase emulsion exceeds 30 mPa·sec during vacuum distillation.

[0012] According to the invention according to <5>, when adding an aqueous medium to an inverse phase emulsion contained in a distillation tank during vacuum distillation, a method for producing a resin particle dispersion liquid is provided, which suppresses a decrease in yield due to adhesion of resin to the inner wall surface of the distillation tank, as compared with a case where the distillation recovery rate per unit heat transfer area of the distillation tank exceeds 60 kg / h / m 2 Furthermore.

[0013] According to the invention according to <6>, a method for producing a resin particle dispersion liquid is provided, which suppresses coarsening of resin particles, as compared with a case where the temperature T1 of the inverse phase emulsion is less than 25°C or exceeds (glass transition temperature Tg of the resin - 1°C), the temperature T2 of the heating fluid flowing inside the heating section exceeds 95°C, or the relationship between T1 and T2 is T1>T2 when adding an aqueous medium to the inverse phase emulsion contained in the distillation tank during vacuum distillation.

[0014] According to the invention according to <7>, a method for producing a resin particle dispersion liquid is provided, which suppresses coarsening of resin particles, as compared with a case where the temperature T3 of the aqueous medium added to the inverse phase emulsion contained in the distillation tank during vacuum distillation exceeds (glass transition temperature Tg of the resin - 1°C).

[0015] According to the invention according to <8>, a method for producing a resin particle dispersion liquid is provided, which reduces the recovery amount of the distillate from the distillation tank, as compared with a case where the temperature T3 of the aqueous medium is less than (glass transition temperature Tg of the resin - 30°C).

[0016] According to the invention according to <9>, a method for producing a resin particle dispersion liquid is provided, which reduces the recovery amount of the distillate from the distillation tank, as compared with a case where the addition rate of the aqueous medium added to the inverse phase emulsion contained in the distillation tank during vacuum distillation fluctuates beyond the range of T1±5 of the temperature T1 of the inverse phase emulsion when adding the aqueous medium.

[0017] According to the invention according to <10>, there is provided a method for producing a resin particle dispersion liquid that suppresses a decrease in the yield due to the adhesion of resin to the inner wall surface of a distillation tank, as compared with the case of performing production of a phase inversion emulsion and vacuum distillation in the distillation tank.

[0018] According to the invention according to <11> or <12>, in a method for producing a resin particle dispersion liquid having a step of preparing a phase inversion emulsion in which a resin is phase-inverted using an organic solvent and an aqueous medium, and a step of removing the organic solvent from the phase inversion emulsion by vacuum distillation using a specific vacuum distillation apparatus, during the vacuum distillation, compared with the case where an aqueous medium is not added to the phase inversion emulsion accommodated in the distillation tank of the specific vacuum distillation apparatus, there is provided a method for producing a resin particle dispersion liquid that suppresses a decrease in the yield due to the adhesion of resin to the inner wall surface of the distillation tank even when a resin having a polar group or an acid value is applied as the resin.

[0019] According to the invention according to <13>, there is provided a method for producing a resin particle dispersion liquid in which the recovery amount of the distillate from the distillation tank is reduced, as compared with the case where the content of the residual organic solvent in the resin particle dispersion liquid is less than 25 ppm.

[0020] According to the invention according to <15> or <16>, in a method for producing a resin particle dispersion liquid having a step of preparing a phase inversion emulsion in which a resin is phase-inverted using an organic solvent and an aqueous medium, and a step of removing the organic solvent from the phase inversion emulsion by vacuum distillation using a specific vacuum distillation apparatus, during the vacuum distillation, compared with the case where the method for producing a resin particle dispersion liquid in which an aqueous medium is not added to the phase inversion emulsion accommodated in the distillation tank of the specific vacuum distillation apparatus is applied, there is provided a method for producing a low-cost electrostatic charge image developing toner or an electrostatic charge image developing toner.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Best Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments which are examples of the present invention will be described. These descriptions and examples are illustrative of the present invention and do not limit the present invention.

[0023] In this specification, a numerical range indicated using "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other stepwise descriptions. Also, in the numerical ranges described in this disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0024] In this specification, the term "step" includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step is achieved.

[0025] When an embodiment is described with reference to the drawings in this specification, the configuration of the embodiment is not limited to the configuration shown in the drawings. Also, the sizes of the members in each figure are conceptual, and the relative relationships of the sizes between the members are not limited thereto.

[0026] In this specification, each component may contain a plurality of corresponding substances. When referring to the amount of each component in a composition in this disclosure, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition.

[0027] In this specification, the "toner for electrostatic charge image development" is also simply referred to as "toner".

[0028] <Method for Producing Resin Particle Dispersion> The method for producing a resin particle dispersion according to this embodiment includes a step of preparing a phase inversion emulsion in which a resin is phase-inverted and emulsified using an organic solvent and an aqueous medium, and a step of removing the organic solvent from the phase inversion emulsion by vacuum distillation. Then, in the method for producing a resin particle dispersion according to this embodiment, vacuum distillation is carried out using a specific vacuum distillation apparatus, and during the vacuum distillation, an aqueous medium is added to the phase inversion emulsion contained in the distillation tank.

[0029] The specific vacuum distillation apparatus is a distillation tank in which the phase inversion emulsion is contained, a heating unit that flows a heating fluid inside to heat the tank wall of the distillation tank, a stirring unit provided in the distillation tank, the stirring unit having a stirring shaft and one or a plurality of trough-shaped stirring blades attached to the stirring shaft that stir the phase inversion emulsion by rotation and pump up the phase inversion emulsion to form a liquid film of the phase inversion emulsion on the heat transfer surface of the distillation tank above the liquid level of the phase inversion emulsion, and is a vacuum distillation apparatus including these components.

[0030] In the method for producing a resin particle dispersion according to this embodiment, a decrease in the yield due to the adhesion of the resin to the inner wall surface of the distillation tank is suppressed. The reason is presumably as follows.

[0031] As an example, the resin particle dispersion is produced by dissolving a resin in an organic solvent, mixing it with water and phase-inverting and emulsifying it to finely disperse it in an aqueous medium, and then removing the organic solvent by vacuum distillation. It is known that a specific vacuum distillation apparatus is used for vacuum distillation.

[0032] In the specific vacuum distillation apparatus, due to the rotation of the trough-shaped stirring blades, the phase inversion emulsion is stirred and the phase inversion emulsion contained in the vacuum distillation (hereinafter also referred to as "the contained phase inversion emulsion") is pumped up to form a liquid film of the phase inversion emulsion on the heat transfer surface of the distillation tank above the liquid level of the contained phase inversion emulsion. By forming a liquid film of the phase inversion emulsion on the heat transfer surface of the distillation tank, even if the volume of the phase inversion emulsion decreases due to the evaporation of the organic solvent and the aqueous medium, the area of contact between the phase inversion emulsion and the heat transfer surface of the distillation tank can be maximized.

[0033] However, when the organic solvent and the aqueous medium evaporate by vacuum distillation and the solid content concentration of the contained inverse phase emulsion increases, the solid content concentration of the liquid film of the inverse phase emulsion formed on the heat transfer surface of the distillation tank becomes excessively high because the organic solvent and the aqueous medium evaporate before dripping down to the contained inverse phase emulsion. In particular, the liquid film near the liquid surface of the contained inverse phase emulsion tends to have an excessively high solid content concentration. When the solid content concentration increases, the liquid viscosity also increases, and as a result, resin adheres to the heat transfer surface (i.e., the inner wall surface) of the distillation tank.

[0034] On the other hand, in the method for producing a resin particle dispersion according to the present embodiment, an aqueous medium is added to the contained inverse phase emulsion during vacuum distillation. Then, even if the organic solvent and the aqueous medium evaporate by vacuum distillation, the solid content concentration of the inverse phase emulsion is less likely to become excessively high. Therefore, the liquid film near the liquid surface of the contained inverse phase emulsion is less likely to have an excessively high solid content concentration due to the evaporation of the organic solvent and the aqueous medium, and the solid content concentration of the liquid film of the inverse phase emulsion formed on the heat transfer surface of the distillation tank is also less likely to become excessively high. As a result, an excessive increase in the liquid viscosity of the liquid film of the inverse phase emulsion is suppressed, and adhesion to the heat transfer surface (i.e., the inner wall surface) of the distillation tank is suppressed.

[0035] From the above, it is presumed that the method for producing a resin particle dispersion according to the present embodiment suppresses a decrease in the yield caused by the adhesion of the resin to the inner wall surface of the distillation tank.

[0036] Hereinafter, the method for producing a resin particle dispersion according to the present embodiment will be described in detail.

[0037] (Manufacturing apparatus for resin particle dispersion) First, an outline of the manufacturing apparatus used in the method for producing a resin particle dispersion according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram showing an example of the manufacturing apparatus used in the method for producing a resin particle dispersion according to the present embodiment. The manufacturing apparatus shown in FIG. 1 includes an emulsifying apparatus 100, a vacuum distillation apparatus 200, and a distillate recovery apparatus 300.

[0038] The emulsifying device 100 includes, for example, an emulsifying tank 102 for supplying a resin, a neutralizing agent, an organic solvent, and an aqueous medium to invert the phase of the resin, a heating unit 104 (so-called jacket) for heating the tank wall of the emulsifying tank 102, and a stirring unit 106 provided in the emulsifying tank 102 for inverting the phase and emulsifying. The emulsifying tank 102 is connected with supply lines 108 for supplying a resin, a neutralizing agent, an organic solvent, and an aqueous medium to the emulsifying tank 102, respectively.

[0039] The vacuum distillation device 200 includes, for example, a distillation tank 202 for containing the phase-inverted emulsion, a heating unit 204 (so-called jacket) for flowing a heating fluid inside to heat the tank wall of the distillation tank 202, and a stirring unit 206 provided in the distillation tank 202 for stirring the phase-inverted emulsion contained in the distillation tank 202. The distillation tank 202 is connected with a vacuum pump for reducing the pressure inside the distillation tank 202 via a solvent discharge line 304 and a condenser 306 described later. Note that the details of the vacuum distillation device 200 will be described later.

[0040] Here, the emulsifying tank 102 and the distillation tank 202 are connected by an emulsion transfer line 112 via a pump 110.

[0041] The distillate recovery device 300 includes, for example, a recovery tank 302, a solvent discharge line 304 connected to the recovery tank 302 and the distillation tank 202 with the other end connected to the recovery tank 302, a condenser 306 provided in the path of the solvent discharge line 304 for condensing the organic solvent and the aqueous medium evaporated from the phase-inverted emulsion contained in the distillation tank 202, and a vacuum pump 308 for evacuating and reducing the pressure inside the distillation tank 302 via the solvent discharge line 304 and the condenser 306.

[0042] In the manufacturing device shown in FIG. 1, in the emulsifying device 100, a resin, a neutralizing agent, an organic solvent, and an aqueous medium are supplied from each supply line 108 to the emulsifying tank 102, and while being heated by the heating unit 104 and stirred by the stirring unit 106, the phase inversion and emulsification of the resin are performed to obtain a phase-inverted emulsion.

[0043] Next, the phase-inverted emulsion is transferred from the emulsifying tank 102 to the distillation tank 202 through the emulsion transfer line 110 by the pump 110.

[0044] Next, in the vacuum distillation apparatus 200, while heating by the heating unit 204, stirring by the stirring unit 206, and reducing the pressure inside the distillation tank 202 by the vacuum pump 308, the organic solvent and the aqueous medium are evaporated from the phase-inverted emulsion. In the distillate recovery apparatus 300, the organic solvent and the aqueous medium evaporated from the phase-inverted emulsion are sent to the condenser 306 through the solvent discharge line 304, condensed in the condenser, and then recovered in the recovery tank 302.

[0045] Then, when the organic solvent is removed from the phase-inverted emulsion, a resin particle dispersion is obtained.

[0046] Note that the production apparatus used in the method for producing the resin particle dispersion according to the present embodiment is not limited to the above apparatus, and a well-known apparatus can be adopted except that the vacuum distillation apparatus 200 corresponds to the specific vacuum distillation apparatus.

[0047] Next, the details of the steps of the method for producing the resin particle dispersion according to the present embodiment will be described. Note that the reference numerals will be omitted in the description.

[0048] (Phase-inverted Emulsion Preparation Step) In the phase-inverted emulsion preparation step, a phase-inverted emulsion in which a resin is phase-inverted is prepared using an organic solvent and an aqueous medium. The phase-inverted emulsion is obtained by the phase-inversion emulsification method. The phase-inversion emulsification method is a method in which an aqueous medium (i.e., the W phase) is introduced into an oil-phase dispersion (i.e., a resin solution that becomes the O phase) in which a resin is dissolved in an organic solvent in which the resin is soluble, so that the conversion (so-called phase inversion) of the resin from W / O to O / W is performed, the oil-phase dispersion is made into a discontinuous phase, and the resin is dispersed in a particulate state in the aqueous medium.

[0049] Examples of the method for producing the phase-inverted emulsion include, for example, the following method. 1) A method of dissolving a resin in an organic solvent, adding a neutralizing agent to the resulting resin solution to neutralize the resin, and then adding an aqueous medium to the resin solution for phase inversion emulsification. 2) A method of dissolving a resin in a solvent containing an organic solvent and a neutralizing agent, neutralizing the resin, and then adding an aqueous medium to the resin solution for phase inversion emulsification. 3) A method of dissolving a resin in a solvent containing an organic solvent, a neutralizing agent, and an aqueous medium, neutralizing the resin, and then adding an aqueous medium to the resin solution for phase inversion emulsification.

[0050] The production of the phase inversion emulsion is carried out, for example, by a well-known emulsifying device such as an emulsifying tank with a stirring blade. When dissolving the resin in an organic solvent, in addition to the resin and the organic solvent, an aqueous solvent and a neutralizing agent may be mixed. The order of charging the resin and the organic solvent into the emulsifying tank is not particularly restricted. However, when the resin is easily soluble in the organic solvent, from the viewpoint of dissolution time, it is preferable to charge all of the organic solvent or a part of the organic solvent and then charge the resin. The pipe for charging the resin into the emulsifying tank can be freely selected according to the pulverized diameter of the resin to be charged, etc. For example, in order to suppress the dust flying during resin charging, a pipe that moves up and down to the lower part of the emulsifying tank may be used. There are no particular restrictions on the position, number, and shape of the nozzles for adding water to the resin solution obtained by dissolving the resin in an organic solvent. For example, the nozzles may be immersed in the liquid. In the case of a large-scale facility, it is preferable to add using a plurality of two or more pipes or a nozzle of a shower head type so as to diffuse from the upper part of the emulsifying tank to the liquid surface.

[0051] - Resin - The resin may be any resin capable of phase inversion emulsification. Examples of the resin include homopolymers of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (e.g., ethylene, propylene, butadiene, etc.), or vinyl resins composed of copolymers obtained by combining two or more of these monomers. Examples of the resin also include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, modified rosin, mixtures of these and the above vinyl resins, or graft polymers obtained by polymerizing vinyl monomers in the coexistence of these. These resins may be used alone or in combination of two or more.

[0052] The resin preferably has polar groups such as carboxyl groups, sulfonic acid groups, and hydroxy groups, and particularly preferably has an acid value. When the solid content concentration increases due to ionic bonds between these polar groups, the liquid viscosity tends to increase, and the resin is likely to adhere to the inner wall surface of the distillation tank. However, in the method for producing the resin particle dispersion according to the present embodiment, the adhesion of the resin to the inner wall surface of the distillation tank is suppressed, and a decrease in the yield due to the adhesion of the resin can be suppressed.

[0053] It is preferable to apply an amorphous resin as the resin. However, a crystalline resin (e.g., a crystalline polyester resin) may also be applied. Here, an amorphous resin refers to a resin that, in thermal analysis measurements using differential scanning calorimetry (DSC), has only a step-like endothermic change rather than a distinct endothermic peak, is a solid at room temperature, and thermoplastics at a temperature above the glass transition temperature. On the other hand, a crystalline resin refers to a resin that has a distinct endothermic peak in differential scanning calorimetry (DSC) rather than a step-like change in the endothermic amount. Specifically, for example, a crystalline resin means that the half-width of the endothermic peak measured at a heating rate of 10 °C / min is within 10 °C, and an amorphous resin means a resin with a half-width exceeding 10 °C or a resin for which no distinct endothermic peak is observed.

[0054] An amorphous resin will be described. Examples of amorphous resins include known amorphous resins such as amorphous polyester resins, amorphous vinyl resins (e.g., styrene-acrylic resins, etc.), epoxy resins, polycarbonate resins, and polyurethane resins. Among these, amorphous polyester resins and amorphous vinyl resins (especially styrene-acrylic resins) are preferred, and amorphous polyester resins are more preferred. It is also a preferred embodiment to use an amorphous polyester resin and a styrene-acrylic resin in combination as the amorphous resin. Further, it is also a preferred embodiment to apply an amorphous resin having an amorphous polyester resin segment and a styrene-acrylic resin segment as the amorphous resin.

[0055] · Amorphous polyester resin Examples of amorphous polyester resins include condensation polymers of polyvalent carboxylic acids and polyvalent alcohols. As the amorphous polyester resin, commercially available products may be used, or synthesized ones may be used.

[0056] Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms) alkyl esters thereof. Among these, aromatic dicarboxylic acids are preferred as the polyvalent carboxylic acid. The polyvalent carboxylic acid may be used in combination with a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure together with the dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms) alkyl esters thereof. The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0057] Examples of the polyhydric alcohol include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), aromatic diols (e.g., ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred as the polyhydric alcohol, and aromatic diols are more preferred. The polyhydric alcohol may be used in combination with a trivalent or higher polyhydric alcohol having a crosslinked structure or a branched structure together with the diol. Examples of the trivalent or higher polyhydric alcohol include glycerin, trimethylolpropane, pentaerythritol. The polyhydric alcohol may be used alone or in combination of two or more.

[0058] The amorphous polyester resin is obtained by a known production method. Specifically, for example, it can be obtained by a method in which the polymerization temperature is set to 180°C or higher and 230°C or lower, the pressure inside the reaction system is reduced as necessary, and the reaction is carried out while removing water and alcohol generated during condensation. When the monomer of the raw material does not dissolve or is not compatible at the reaction temperature, a high-boiling solvent may be added as a dissolution aid to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the dissolution aid. When there is a monomer with poor compatibility in the copolymerization reaction, it is advisable to first condense the monomer with poor compatibility with the acid or alcohol intended for polycondensation and then carry out polycondensation with the main component.

[0059] The properties of the resin will be described. The acid value of the resin is preferably 8 mgKOH / g or more and 20 mgKOH / g or less, more preferably 10 mgKOH / g or more and 16 mgKOH / g or less.

[0060] The acid value is determined by the neutralization titration method defined in JIS K0070 (1992). Specifically, it is as follows. An appropriate amount of the sample is taken, 100 ml of a solvent (diethyl ether / ethanol mixture), and a few drops of an indicator (phenolphthalein solution) are added, and the mixture is thoroughly shaken on a water bath until the sample is completely dissolved. This is titrated with a 0.1 mol / l potassium hydroxide ethanol solution, and the end point is reached when the pale red color of the indicator persists for 30 seconds. When the acid value is A, the sample amount is S (g), the 0.1 mol / l potassium hydroxide ethanol solution used for titration is B (ml), and f is the factor of the 0.1 mol / l potassium hydroxide ethanol solution, it is calculated as A = (B × f × 5.611) / S.

[0061] The glass transition temperature (Tg) of the resin is preferably 50°C or higher and 80°C or lower, more preferably 50°C or higher and 65°C or lower. The glass transition temperature is measured in accordance with JIS 7121-1987 using a differential scanning calorimeter (manufactured by Mac Science: DSC3110, thermal analysis system 001). The melting point of a mixture of indium and zinc is used for temperature correction of the detection part of this apparatus, and the heat of fusion of indium is used for heat quantity correction. The sample is placed in an aluminum pan, and the aluminum pan containing the sample and a control empty aluminum pan are set, and measurement is carried out at a heating rate of 10 °C / min. The glass transition temperature is defined as the temperature at the intersection of the extension lines of the baseline and the rising line in the endothermic part of the DSC curve obtained by measurement.

[0062] The weight average molecular weight (Mw) of the resin is preferably 5000 or more and 1000000 or less, more preferably 7000 or more and 500000 or less. The number average molecular weight (Mn) of the resin is preferably 2000 or more and 100000 or less. The molecular weight distribution Mw / Mn of the resin is preferably 1.5 or more and 100 or less, more preferably 2 or more and 60 or less. The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is carried out using Tosoh's GPC·HLC-8120GPC as the measurement apparatus, using Tosoh's column·TSKgel SuperHM-M (15 cm), and using a THF solvent. The weight average molecular weight and the number average molecular weight are calculated from this measurement result using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

[0063] The amount of the resin used is not particularly limited, and it may be appropriately selected according to the solid content concentration of the obtained resin particle dispersion.

[0064] -Neutralizing agent- Examples of the neutralizing agent include basic compounds that can neutralize polar groups such as carboxyl groups, sulfonic acid groups, and hydroxy groups in the resin. Specifically, examples of the neutralizing agent include organic bases and inorganic alkalis. Examples of the organic base include triethanolamine, diethanolamine, N-methyldiethanolamine, dimethylethanolamine, and the like. Examples of the inorganic alkali include hydroxides of alkali metals (e.g., sodium hydroxide, lithium hydroxide, potassium hydroxide, etc.), carbonates (e.g., sodium carbonate, sodium bicarbonate, etc.), ammonia, and the like. As the neutralizing agent, amines which are weak bases are preferably used in order to prevent hydrolysis of the resin, and ammonia is more preferable. Further, it is particularly preferable to add ammonia in the state of an aqueous ammonia solution.

[0065] The neutralization rate of the resin by the neutralizing agent is 60% or more and less than 150%, but from the viewpoints of improving the yield and narrowing the particle size distribution, 60% or more and less than 145% is more preferable, and 65% or more and 140% or less is even more preferable. That is, the neutralizing agent is used so that the neutralization rate of the resin falls within the above range.

[0066] The neutralization rate of the resin is measured as follows. When the acid value of the resin is AV [mg-KOH / g-resin], the valence of the neutralization rate (i.e., basic substance) to be added is n, the molecular weight of the neutralizing agent (i.e., basic substance) to be added is Mwb, and the addition amount of the neutralizing agent (i.e., basic substance) per 1 g of the resin is mb [g], it is represented by the following calculation formula. Neutralization rate of resin [%]=mb×n×56.1÷Mwb÷AV×1000

[0067] -Organic solvent- Examples of the organic solvent include well-known solvents applicable to phase inversion emulsification. Among these, from the viewpoint of improving the solubility of the resin, the organic solvent preferably contains one or more organic solvents selected from the group consisting of esters and ketones and one or more organic solvents selected from alcohols.

[0068] Examples of the esters include ethyl acetate, butyl acetate, propyl acetate, isopropyl acetate, and the like. Examples of ketones include acetone, methyl ethyl ketone, cyclohexanone, butanone, methyl isobutyl ketone, etc. Examples of alcohols include methanol, ethanol, isopropyl alcohol, n-propanol, n-butanol, diacetone alcohol, 2-ethylhexanol, etc.

[0069] - Aqueous medium - As the aqueous medium, for example, water (such as distilled water, ion-exchanged water, etc.) is applied. The amount of water added to the oil phase medium in which the resin is dissolved in the organic solvent is, for example, an amount that causes phase inversion emulsification and reduces the amount of waste generated. Specifically, the addition amount of water is preferably 50% by mass or more and 2000% by mass or less, more preferably 100% by mass or more and 1000% by mass or less, based on the weight of the resin.

[0070] (Organic solvent removal step) In the organic solvent removal step, the organic solvent is removed from the phase inversion emulsion by vacuum distillation. The vacuum distillation is carried out using the vacuum distillation apparatus 200 shown in FIG. 2. FIG. 2 is a schematic configuration diagram showing an example of the vacuum distillation apparatus 200 used in the method for producing the resin particle dispersion according to the present embodiment.

[0071] The vacuum distillation apparatus 200 shown in FIG. 2 has a distillation tank 202, a heating section 104 (so-called jacket), a stirring section 206, and an aqueous medium supply line 208.

[0072] The distillation tank 202 is a layer in which the phase inversion emulsion is accommodated and the phase inversion emulsion is subjected to vacuum distillation. Of the inner wall surface of the distillation tank 202, the surface corresponding to the heating section 204 is defined as the heat transfer surface 204A. That is, the heat transfer surface of the distillation tank 202 refers to the surface of the inner wall surface of the distillation tank 202 that corresponds to the heating section 204. The distillation tank 202 is connected to the emulsion transfer line 112 and the solvent discharge line 304, respectively (see FIG. 1)

[0073] The heating unit 204 allows a heating fluid to flow therein to heat the tank wall of the distillation tank 202. The heating unit 204 is provided, for example, from the bottom to the side surface of the distillation tank 202. As long as the form of the heating unit 204 is such that it heats the tank wall of the distillation tank 202 until the temperature of the phase inversion emulsion contained in the distillation tank 202 reaches the target temperature, a well-known configuration is adopted. Note that the heating fluid introduced into the heating unit 204 is preferably, for example, steam, heated water, or the like.

[0074] The stirring unit 206 is provided inside the distillation tank 202 and stirs the phase inversion emulsion contained in the distillation tank 202. The stirring unit 206 has a stirring shaft 206A and one or more gutter-shaped stirring blades 206B attached to the stirring shaft.

[0075] The stirring shaft 206A is composed of, for example, a cylindrical member or a columnar member. The stirring shaft 206A is usually arranged such that its axial direction is along the vertical direction.

[0076] The gutter-shaped stirring blade 206B is attached to the stirring shaft 206A and stirs the phase inversion emulsion by rotation. At the same time, the gutter-shaped stirring blade 206B pumps up the phase inversion emulsion to form a liquid film of the phase inversion emulsion on the heat transfer surface 204A of the distillation tank 202 above the liquid level of the phase inversion emulsion. The gutter-shaped stirring blade 206B has a flow path (not shown) through which the phase inversion emulsion flows, and its longitudinal direction is inclined with respect to the stirring shaft 206A. The gutter-shaped stirring blade 206B pumps up the phase inversion emulsion through the flow path by the centrifugal force generated by the rotation of the stirring shaft 206A. The gutter-shaped stirring blade 206B is, for example, a pipe such as a cylindrical or square tube; a half-pipe such as a semi-cylindrical, semi-square tube, or V-shaped tube is applicable. Also, the gutter-shaped stirring blade 206B may be a stirring blade composed of half-pipes at both ends and a pipe in the central part.

[0077] Here, it is preferable that the relationship among the installation angle θ [°] of the trough-shaped stirring blade 206B with respect to the stirring shaft 206A, the rotation speed N [rpm] of the stirring shaft 206A, the inner diameter D [m] of the distillation column 202, and the maximum diameter d [m] of the rotation locus of the trough-shaped stirring blade 206B satisfies the following formulas (1) to (4). Formula (1): 10 ≤ θ ≤ 45 Formula (2): 14 ≤ N·sinθ ≤ 60 Formula (3): 0.4 ≤ D ≤ 5 Formula (4): 0.75 ≤ d / D ≤ 0.95

[0078] The value of "N·sinθ" represents the centrifugal force generated by the rotation of the trough-shaped stirring blade 206B. By satisfying the above Formulas (1) to (2), a good liquid film of the phase-inverted emulsion is likely to be formed on the heat transfer surface 204A of the distillation column 202 while suppressing the scattering of the phase-inverted emulsion. When "D" and "d / D" satisfy Formulas (3) to (4), the distance from the tip of the trough-shaped stirring blade 206B to the heat transfer surface 204A of the distillation column 202 becomes an appropriate distance, and a good liquid film of the phase-inverted emulsion is likely to be formed while suppressing the scattering of the phase-inverted emulsion.

[0079] The stirring unit 206 is not limited to the above configuration, and a well-known configuration is adopted except that it has the trough-shaped stirring blade 206B. Specifically, for example, a well-known stirring device called a wall wetter is adopted.

[0080] The aqueous medium supply line 208 is a supply line for adding an aqueous medium to the contained phase-inverted emulsion during the vacuum distillation of the phase-inverted emulsion in the distillation column 202. As the method for adding the aqueous medium through the aqueous medium supply line 208, a well-known addition method such as dropping from a pipe or dropping from a shower ball may be adopted. The addition of the aqueous medium may be continuous or intermittent. As the aqueous medium, water (such as distilled water, ion-exchanged water, etc.) is applicable.

[0081] In the vacuum distillation apparatus 200 shown in FIG. 2, the phase-inverted emulsion contained in the distillation tank 202 is heated through the heat transfer surface 204A of the distillation tank 202 by the heating unit 204 while being depressurized. At the same time, it is stirred by the stirring unit 206. In the stirring unit 206, the phase-inverted emulsion is stirred by the gutter-shaped stirring blade 206B, and the phase-inverted emulsion is pumped up to form a liquid film of the phase-inverted emulsion on the heat transfer surface 204A of the distillation tank 202 above the liquid level of the phase-inverted emulsion, while performing vacuum distillation to evaporate the organic solvent of the phase-inverted emulsion. During the vacuum distillation, a water medium is added to the phase-inverted emulsion contained in the distillation tank 202 through the water medium supply line 208.

[0082] Here, the vacuum distillation apparatus 200 shown in FIG. 2 stirs the phase-inverted emulsion by a stirring unit having a gutter-shaped stirring blade 206B. When the stirring unit having the gutter-shaped stirring blade 206B is used for phase inversion emulsification, the stirring force is weak, and the dissolution of the resin in the organic solvent may be insufficient. As a result, the adhesion of the resin to the inner wall surface of the distillation tank may be promoted. Therefore, separately, in the emulsification tank 102, it is advisable to produce the phase-inverted emulsion while stirring it with a stirring unit having a strong stirring force, transfer it from the emulsification tank 102 to the distillation tank 202, and perform vacuum distillation. Thereby, the adhesion of the resin to the inner wall surface of the distillation tank is suppressed, and the yield is likely to be improved.

[0083] Note that the vacuum distillation apparatus 200 shown in FIG. 2 is not limited to the above configuration, and a well-known vacuum distillation apparatus is adopted except that the water medium supply line 208 is provided.

[0084] Next, the details of the organic solvent removal step will be described. Hereinafter, the reference numerals will be omitted for the description.

[0085] In the organic solvent removal step, from the viewpoint of suppressing the adhesion of resin particles to the inner wall surface of the distillation tank, it is advisable to add a water medium to the phase-inverted emulsion contained in the distillation tank so as to maintain the solid content concentration of the phase-inverted emulsion in the range of 25% by mass to 45% by mass (preferably in the range of 25% by mass to 40% by mass) during the vacuum distillation. By adding an aqueous medium to the phase-inverted emulsion contained in the distillation tank so that the solid content concentration of the phase-inverted emulsion is maintained within the above range, an increase in the viscosity of the liquid film formed on the heat transfer surface of the distillation tank can be suppressed, and resin sticking can be easily suppressed.

[0086] The solid content concentration of the phase-inverted emulsion is the solid content concentration calculated from the mass and solid content concentration of the phase-inverted emulsion at the start of vacuum distillation, the mass of the distillate recovered by vacuum distillation, and the mass of the aqueous medium added during vacuum distillation. Specifically, when the mass of the resin in the phase-inverted emulsion at the start of vacuum distillation is Wr [kg], the mass of the resin particle dispersion liquid after phase inversion is Wt [kg], the mass of the distillate recovered by vacuum distillation is Wv, and the mass of the aqueous medium added during vacuum distillation is Ww [kg], the solid content concentration is calculated by the following formula. Formula: Solid content concentration = Wr / (Wt - Wr + Ww) The mass of the distillate recovered by vacuum distillation is measured by a scale such as a load cell or the integrated value of a flow meter.

[0087] In the organic solvent removal step, from the viewpoint of suppressing the adhesion of resin particles to the inner wall surface of the distillation tank, it is preferable to add an aqueous medium to the phase-inverted emulsion contained in the distillation tank during vacuum distillation so that the maximum viscosity of the phase-inverted emulsion is maintained in the range of 30 mPa·sec or less (preferably 10 mPa·sec or more and 25 mPa·sec or less). By adding an aqueous medium to the phase-inverted emulsion contained in the distillation tank so that the maximum viscosity of the phase-inverted emulsion is maintained within the above range, an increase in the viscosity of the liquid film formed on the heat transfer surface of the distillation tank can be suppressed, and resin sticking can be easily suppressed.

[0088] The viscosity of the phase-inverted emulsion is measured by a vibrating viscometer (VM-10A, manufactured by Sekonic).

[0089] In the organic solvent removal step, from the viewpoint of suppressing the adhesion of resin particles to the inner wall surface of the distillation tank, when adding an aqueous medium to the phase-inverted emulsion contained in the distillation tank during vacuum distillation, the distillation recovery rate per unit heat transfer surface of the distillation tank is 60 kg / h / m 2 or less (preferably 10 kg / h / m 2 or more and 55 kg / h / m 2It is preferably as follows. When the distillation recovery rate per unit heat transfer area of the distillation tank is within the above range, by adding an aqueous medium to the phase-inverted emulsion contained in the distillation tank, an increase in the viscosity of the liquid film formed on the heat transfer surface of the distillation tank is suppressed, and the sticking of the resin is likely to be suppressed.

[0090] The distillation recovery rate per unit heat transfer area of the distillation tank is measured by the mass change of the recovered distillate per unit time or a flow meter installed in the middle of the pipe to obtain the distillation recovery rate [kg / h], and then divided by the area of the heat transfer surface of the distillation tank [m 2 for calculation.

[0091] In the organic solvent removal step, from the viewpoint of suppressing coarsening of resin particles, when adding an aqueous medium to the phase-inverted emulsion contained in the distillation tank during vacuum distillation, the temperature T1 of the phase-inverted emulsion is 25°C or higher (resin glass transition temperature Tg - 1°C) and lower (preferably 30°C or higher (resin glass transition temperature Tg - 10°C) and lower), the temperature T2 of the heating fluid flowing inside the heating section is 95°C or lower (preferably 50°C or higher and 95°C or lower), and the relationship between T1 and T2 is preferably T1 < T2 (preferably T2 - T1 is 15°C or higher and 55°C or lower). Under the above conditions, by adding an aqueous medium to the phase-inverted emulsion contained in the distillation tank, local temperature changes are less likely to occur when the aqueous medium is added, and the stability of the resin particles is maintained. Therefore, the resin particles are prevented from fusing together and coarsely pulverizing. Note that the temperature T2 of the heating fluid flowing inside the heating section is the temperature of the heating fluid at the inlet where the heating fluid is introduced into the heating section.

[0092] In the organic solvent removal step, from the viewpoint of suppressing coarsening of resin particles, the temperature T3 of the aqueous medium added to the phase-inverted emulsion contained in the distillation tank during vacuum distillation is preferably (resin glass transition temperature Tg - 1°C) or lower (preferably resin glass transition temperature Tg - 10°C) or lower). By setting the temperature T3 of the aqueous medium to (resin glass transition temperature Tg - 1°C) or lower, the heat of the added aqueous medium suppresses the fusion of resin particles together and coarsening pulverization.

[0093] In the organic solvent removal step, from the viewpoint of reducing the recovery amount of the distillate, the temperature T3 of the aqueous medium is preferably 10 °C or higher and (the glass transition temperature Tg of the resin - 1 °C) or lower (preferably 15 °C or higher and (the glass transition temperature Tg of the resin - 1 °C) or lower). By setting the temperature T3 of the aqueous medium to 15 °C or higher, the decrease in the temperature of the phase - inverted emulsion during vacuum distillation is suppressed, and the amount of the aqueous medium in the distillate is reduced. Therefore, the recovery amount of the distillate from the distillation tank is reduced. However, in order to suppress the freezing of the aqueous medium, the temperature T3 of the aqueous medium is preferably 5 °C or higher (preferably 20 °C or higher).

[0094] In the organic solvent removal step, from the viewpoint of reducing the recovery amount of the distillate, the addition rate of the aqueous medium added to the phase - inverted emulsion contained in the distillation tank during vacuum distillation is preferably a variation rate within the range of the temperature T1 ± 5 (preferably within the range of T1 ± 3) of the phase - inverted emulsion when adding the aqueous medium to the phase - inverted emulsion contained in the distillation tank during vacuum distillation. By setting the addition rate of the aqueous medium to the above conditions, the temperature change of the phase - inverted emulsion due to the addition of the aqueous medium is suppressed, and the amount of the aqueous medium in the distillate is reduced. Therefore, the recovery amount of the distillate from the distillation tank is reduced. Note that, for example, the addition rate of the aqueous medium is exemplified as 0.5 kg / hr or more and 3.5 kg / hr or less per unit weight of the resin.

[0095] By removing the organic solvent from the phase - inverted emulsion through the solvent removal step described above, a resin particle dispersion in which resin particles are dispersed can be obtained. Note that after the removal of the organic solvent, the recovered organic solvent, neutralizing agent, aqueous solvent, etc. may be reused for the production of the phase - inverted emulsion. Thereby, cost reduction and environmental load reduction can be achieved.

[0096] Here, a surfactant may be added to the obtained resin particle dispersion. When the resin particle dispersion contains a surfactant, the dispersibility of the resin particles is improved, and the storage stability of the dispersion is enhanced.

[0097] Examples of surfactants include various surfactants such as anionic surfactants, amphoteric surfactants, cationic surfactants, and nonionic surfactants. Among these, from the viewpoint of improving the storage stability of the resin particle dispersion, an anionic surfactant is preferred as the surfactant.

[0098] Examples of anionic surfactants include carboxylic acid type, sulfate ester type, sulfonic acid type, and phosphate ester type anionic surfactants. Examples of anionic surfactants include, for example, fatty acid salts, rosin acid salts, naphthenic acid salts, ether carboxylates, alkenyl succinates, primary alkyl sulfates, secondary alkyl sulfates, alkyl polyoxyethylene sulfates, alkyl phenyl polyoxyethylene sulfates, monoacyl glycerol sulfates, acyl amino sulfate ester salts, sulfated oils, sulfated fatty acid alkyl esters, α-olefin sulfonates, secondary alkane sulfonates, α-sulfo fatty acid salts, acyl isethionates, dialkyl sulfosuccinates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl diphenyl ether disulfonates, petroleum sulfonates, lignin sulfonates, alkyl phosphates, alkyl polyoxyethylene phosphates, alkyl phenyl polyoxyethylene phosphates, perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphate esters.

[0099] Among these, from the viewpoint of improving the storage stability of the resin particle dispersion, the anionic surfactant is more preferably a sulfate ester type or sulfonic acid type anionic surfactant, and particularly preferably a sulfonic acid type anionic surfactant.

[0100] From the viewpoint of improving the storage stability of the resin particle dispersion, the content of the surfactant is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less based on the resin.

[0101] (Properties of Resin Particle Dispersion) In the resin particle dispersion according to this embodiment, the volume average particle diameter of the resin particles is preferably 65 nm or more and 220 nm or less, and more preferably 90 nm or more and 200 nm or less. Even if the volume average particle diameter of the resin particles in the resin particle dispersion according to this embodiment is within the above range, the resin particle dispersion has a high yield and a narrow particle size distribution.

[0102] The volume average particle diameter of the resin particles is measured using the particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (for example, LA-700 manufactured by Horiba, Ltd.). For the divided particle size ranges (channels), the cumulative distribution is subtracted from the small particle size side with respect to the volume, and the particle diameter at which the cumulative value is 50% for all particles is measured as the volume average particle diameter D50v.

[0103] In the resin particle dispersion according to this embodiment, the content of the residual organic solvent is preferably 25 ppm or more and 3000 ppm or less, and more preferably 100 ppm or more and 1500 ppm or less. Note that ppm is the ratio based on mass with respect to the resin particle dispersion after removal of the organic solvent. When the content of the residual organic solvent in the resin particle dispersion is 25 ppm or more, it is easy to suppress the decrease in the yield caused by the adhesion of the resin to the inner wall surface of the storage tank. This is because the resin particles containing the organic solvent have a certain degree of flexibility and are considered to be easily maintain the dispersion stability against the stress of foam breakage and high solid content concentration on the tank wall surface. In addition, when the content of the residual organic solvent in the resin particle dispersion is suppressed to 3000 ppm or less, the aggregation of the resin particles is suppressed and the storage stability of the resin particle dispersion is improved. To make the content of the residual organic solvent within the above range, for example, there is a method of calculating in advance the amount of distillate recovered from the amount of the phase inversion emulsion before distillation and the amount of the organic solvent component contained therein.

[0104] The solid content concentration of the resin particle dispersion according to this embodiment may be appropriately selected as needed, but is preferably 1% by mass or more and 60% by mass or less, more preferably 5% by mass or more and 50% by mass or less, and particularly preferably 10% by mass or more and 50% by mass or less.

[0105] (Use) The method for producing the resin particle dispersion according to this embodiment is typically applicable to the method for producing a toner resin particle dispersion. Other uses include those for inkjet ink, cosmetics, powder coatings, various coating paints, electronic paper ink, and the like.

[0106] <Method for manufacturing toner / Toner> The method for manufacturing a toner according to this embodiment is In a dispersion containing resin particles obtained by the method for producing a resin particle dispersion according to this embodiment, at least the resin particles are aggregated to form aggregated particles (hereinafter, the aggregated particle formation step), and heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and unite the aggregated particles to form toner particles (hereinafter, the aggregation and unification step), and has.

[0107] The toner according to this embodiment is a toner having toner particles obtained by the method for manufacturing a toner according to the above-described embodiment.

[0108] Hereinafter, the details of each step will be described. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described. However, the colorant and the release agent are used as necessary. Of course, other additives other than the colorant and the release agent may be used.

[0109] - Particle dispersion preparation step - In the particle dispersion preparation step, a colorant particle dispersion and a release agent dispersion are prepared together with the resin particle dispersion. · Resin particle dispersion The resin particle dispersion is produced according to the method for producing a resin particle dispersion according to the above-described embodiment. However, a resin particle dispersion other than the resin particle dispersion obtained by the method for producing a resin particle dispersion according to this embodiment may be used in combination.

[0110] ·Colorant Particle Dispersion Liquid The colorant particle dispersion liquid is a dispersion liquid in which at least a colorant is dispersed in an aqueous medium. Examples of the colorant include various pigments such as carbon black, chrome yellow, Hansa yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watchung red, permanent red, brilliant carmine 3B, brilliant carmine 6B, duPont oil red, pyrazolone red, resorcin red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate, or various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, thiazole-based dyes, etc. The colorant may be used alone or in combination of two or more.

[0111] The colorant is dispersed in the aqueous medium by a known method. For example, a rotary shear type homogenizer, a media type disperser such as a ball mill, a sand mill, an attritor, or a high-pressure counter-collision type disperser is preferably used. Further, the colorant may be dispersed in the aqueous medium using a polar ionic surfactant and a homogenizer to prepare a colorant particle dispersion liquid.

[0112] The volume average particle diameter of the colorant is preferably 1 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.01 μm or more and 0.5 μm or less. Examples of the dispersant added to further stabilize the dispersion stability of the colorant in the aqueous medium and lower the energy of the colorant in the toner include rosin, rosin derivatives, coupling agents, polymer dispersants, etc.

[0113] ·Release agent particle dispersion liquid The release agent particle dispersion liquid is a dispersion liquid in which at least a release agent is dispersed in an aqueous medium. Examples of the release agent include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; ester waxes such as fatty acid esters and montanic acid esters; and the like. The release agent is not limited thereto. The release agent may be used alone or in combination of two or more. The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, more preferably 60°C or higher and 100°C or lower. The melting temperature is determined by the "melting peak temperature" described in the method for determining the melting temperature of JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics" from the DSC curve obtained by differential scanning calorimetry (DSC).

[0114] The release agent is dispersed in the aqueous medium by a known method. For example, a rotary shear type homogenizer, a media type disperser such as a ball mill, a sand mill, or an attritor, or a high-pressure counter-collision type disperser is preferably used. Further, the release agent may be dispersed in an aqueous solvent using a polar ionic surfactant and a homogenizer to prepare a release agent particle dispersion liquid. The volume average particle diameter of the release agent particles is preferably 1 μm or less, more preferably 0.01 μm or more and 1 μm or more.

[0115] -Agglomerated particle formation step- Next, the colorant particle dispersion liquid and the release agent particle dispersion liquid are mixed with the resin particle dispersion liquid. Then, in the mixed dispersion liquid, the resin particles, the colorant particles, and the release agent particles are hetero-aggregated to form agglomerated particles containing the resin particles, the colorant particles, and the release agent particles, which have a diameter close to the diameter of the target toner particles.

[0116] Specifically, for example, a flocculant is added to the mixed dispersion liquid, the pH of the mixed dispersion liquid is adjusted to acidic (for example, the pH is 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. Then, the temperature is heated to the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles is -30°C or more and -10°C or less), and the particles dispersed in the mixed dispersion liquid are aggregated to form aggregated particles. In the aggregated particle formation step, for example, the flocculant may be added at room temperature (for example, 25°C) while stirring the mixed dispersion liquid with a rotary shear homogenizer, the pH of the mixed dispersion liquid is adjusted to acidic (for example, the pH is 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. Then, the above heating may be performed.

[0117] Examples of the flocculant include surfactants with opposite polarities to the surfactants used as dispersants added to the mixed dispersion liquid, inorganic metal salts, and metal complexes with a valence of 2 or more. In particular, when a metal complex is used as the flocculant, the amount of surfactant used is reduced and the charging characteristics are improved. An additive that forms a complex or a similar bond with the metal ions of the flocculant may be used as necessary. As this additive, a chelating agent is preferably used.

[0118] Examples of the inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. As the chelating agent, a water-soluble chelating agent may be used. Examples of the chelating agent include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA). The addition amount of the chelating agent is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, based on 100 parts by mass of the resin particles.

[0119] -Fusion and Unification Step- Next, the aggregated particle dispersion in which the aggregated particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature equal to or higher than 10 to 30 °C higher than the glass transition temperature of the resin particles), so that the aggregated particles are fused and united to form toner particles.

[0120] Through the above steps, toner particles are obtained. Note that after obtaining the aggregated particle dispersion in which the aggregated particles are dispersed, the aggregated particle dispersion and the resin particle dispersion in which the resin particles are dispersed are further mixed, and aggregated so that the resin particles further adhere to the surface of the aggregated particles to form second aggregated particles. Then, the second aggregated particle dispersion in which the second aggregated particles are dispersed is heated to fuse and unite the second aggregated particles to form toner particles having a core / shell structure, and toner particles may be manufactured through these steps.

[0121] Here, after the fusion and unification step, the toner particles formed in the solution are dried through known washing steps, solid-liquid separation steps, and drying steps to obtain toner particles in a dried state. In the washing step, it is preferable to perform substitution washing sufficiently with ion-exchanged water from the viewpoint of chargeability. Also, in the solid-liquid separation step, although there is no particular limitation, it is preferable to perform suction filtration, pressure filtration, etc. from the viewpoint of productivity. Also, the drying step is not particularly limited in method, but it is preferable to perform freeze drying, airflow drying, fluidized drying, vibration-type fluidized drying, etc. from the viewpoint of productivity.

[0122] Then, the toner and its manufacturing method according to this embodiment are manufactured, for example, by adding and mixing an external additive to the obtained toner particles in a dried state. The mixing may be performed, for example, by a V blender, a Henschel mixer, a Lodige mixer, etc. Further, if necessary, coarse particles of the toner may be removed using a vibrating sieve, an air classifier, etc.

[0123] Here, examples of the external additive include inorganic particles. Examples of the inorganic particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, and the like.

[0124] The surface of the inorganic particles as the external additive is preferably subjected to a hydrophobization treatment. The hydrophobization treatment is performed, for example, by immersing the inorganic particles in a hydrophobizing agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane-based coupling agents, silicone oils, titanate-based coupling agents, aluminum-based coupling agents, and the like. These may be used alone or in combination of two or more. The amount of the hydrophobizing agent is usually, for example, 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the inorganic particles.

[0125] Examples of the external additive also include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning agents (for example, metal salts of higher fatty acids typified by zinc stearate, particles of fluorine-based high molecular weight substances), and the like.

[0126] The amount of the external additive added is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.01% by mass or more and 2.0% by mass or less, based on the toner particles.

[0127] - Toner characteristics - In the toner according to the present embodiment, the toner particles may be single-layer structured toner particles or so-called core-shell structured toner particles composed of a core part (core particles) and a coating layer (shell layer) covering the core part. Here, the core-shell structured toner particles preferably include a core part composed of a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer composed of a binder resin.

[0128] The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, more preferably 4 μm or more and 8 μm or less.

[0129] In addition, various average particle diameters and various particle size distribution indices of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter, Inc.), and the electrolyte used is ISOTON-II (manufactured by Beckman Coulter, Inc.). At the time of measurement, as a dispersant, 0.5 mg or more and 50 mg or less of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant (sodium alkylbenzene sulfonate is preferred). This is added to 100 ml or more and 150 ml or less of the electrolyte. The electrolyte in which the sample is suspended is subjected to a dispersion treatment for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm or more and 60 μm or less is measured using an aperture having an aperture diameter of 100 μm with a Coulter Multisizer II. The number of particles to be sampled is 50,000. Based on the measured particle size distribution, cumulative distributions of volume and number are drawn for the particle size ranges (channels) divided, and the particle diameter at which the cumulative value becomes 16% is defined as the volume particle diameter D16v, the number particle diameter D16p, the particle diameter at which the cumulative value becomes 50% is defined as the volume average particle diameter D50v, the cumulative number average particle diameter D50p, and the particle diameter at which the cumulative value becomes 84% is defined as the volume particle diameter D84v and the number particle diameter D84p. Using these, the volume particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 and the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 and is calculated as such.

[0130] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, more preferably 0.95 or more and 0.98 or less.

[0131] The average circularity of the toner particles is obtained by (circumference equivalent to a circle) / (circumference) [(circumference of a circle having the same projected area as the particle image) / (circumference of the particle projection image)]. Specifically, it is a value measured by the following method. First, toner particles to be measured are aspirated and collected, a flat flow is formed, and stroboscopic light emission is instantaneously performed to capture a particle image as a still image, which is obtained by a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation) that analyzes the particle image. The number of samplings when obtaining the average circularity is set to 3500 pieces. When the toner has an external additive, toner particles (developer) to be measured are dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additive has been removed.

[0132] <Electrostatic charge image developer> The electrostatic charge image developer according to the present embodiment includes at least the toner according to the present embodiment. The electrostatic charge image developer according to the present embodiment may be a one-component developer containing only the toner according to the present embodiment, or may be a two-component developer in which the toner and a carrier are mixed.

[0133] There is no particular limitation on the carrier, and known carriers can be mentioned. Examples of the carrier include a coated carrier in which a coating resin is coated on the surface of a core material made of magnetic powder; a magnetic powder-dispersed carrier in which magnetic powder is dispersed and blended in a matrix resin; a resin-impregnated carrier in which porous magnetic powder is impregnated with resin; and the like. The magnetic powder-dispersed carrier and the resin-impregnated carrier may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

Examples

[0134] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples. In the following description, unless otherwise specified, all "parts" and "%" are based on mass.

[0135] <Synthesis of polyester resin (1)> Into a reaction vessel equipped with a stirrer, a thermometer, a condenser (i.e., a condenser), and a nitrogen gas inlet tube, 5 mol parts of a bisphenol A ethylene oxide 2 mol adduct, 45 mol parts of a bisphenol A propylene oxide 2 mol adduct, 40 mol parts of terephthalic acid, 10 mol parts of isophthalic acid, and 10 mol parts of n-dodecenyl succinic acid were used as raw materials, and dibutyltin oxide was added as a catalyst. Nitrogen gas was introduced into the vessel to maintain an inert atmosphere and the temperature was raised. After that, a co-condensation polymerization reaction was carried out at 230 °C for about 12 hours, and then the pressure was gradually reduced at 200 °C to synthesize a polyester resin (1). The weight average molecular weight (Mw) of the obtained polyester resin (1) was 17,100, the acid value was 12.5 mgKOH / g, the glass transition temperature (Tg) was 58 °C, and the melting point (Tm) was 109 °C.

[0136] <Preparation of the phase inversion emulsion (1)> To a reaction tank equipped with a stirrer, a condenser (i.e., a condenser), and a thermometer, 100 parts of polyester resin (1) as a resin, 70 parts of ethyl acetate and 15 parts of isopropanol with respect to the resin as organic solvents were added. Then, it was stirred at 50 °C for 30 minutes to dissolve the resin in the organic solvent. 5 parts of 10 mass% aqueous ammonia with respect to the resin was added to 185 parts of the obtained resin solution as a neutralizing agent, and after setting the neutralization rate to 132%, 330 parts of pure water at 40 °C was gradually added to obtain a phase inversion emulsion (1).

[0137] <Example 1> <Preparation of the amorphous polyester resin particle dispersion (1)> 520 parts of the phase inversion emulsion (1) was transferred to the distillation tank of the vacuum distillation apparatus shown in Figure 2. Calculating the solid content concentration of the phase inversion emulsion after transfer, it was 19%. The conditions of the vacuum distillation apparatus shown in Figure 2 were as follows. · Grooved stirring blade: Half-cut pipe · Installation angle θ [°] of the grooved stirring blade with respect to the stirring shaft: 20° · Rotation speed N [rpm] of the stirring shaft: 85 rpm · Inner diameter D [m] of the distillation tank: 4 m · Maximum diameter d [m] of the rotation locus of the grooved stirring blade: 3.4 m · N·sinθ = 29 rad / m ·d / D = 0.85

[0138] Subsequently, the jacket water temperature was set to 80°C, and it was gradually lowered to the pressure at which the temperature inside the tank became 35°C. When the solid content concentration of the phase inversion emulsion (solid content concentration of the phase inversion emulsion when water is added) reached 35% (liquid viscosity 10 mPa·sec) and the temperature T1 of the phase inversion emulsion reached 35°C, 50 parts of water at 20°C (temperature T3) was added to lower the solid content concentration of the phase inversion emulsion (solid content concentration of the phase inversion emulsion after water addition) to 30%. The distillation recovery rate during water addition was 35 kg / h / m 2 It was. The jacket water temperature T3 during water addition was 80°C. The distillate was sampled from the distillation tank in a timely manner. By the amount of the distillate recovered when the residual organic solvent concentration reached 500 ppm by gas chromatography, while lowering the jacket temperature to 40°C, the vacuum distillation was terminated by returning to normal pressure, and an amorphous polyester resin particle dispersion (1) was obtained by passing through a filter with an opening of 106 μm. The maximum solid content concentration of the phase inversion emulsion during vacuum distillation was 38%, and the maximum viscosity of the phase inversion emulsion during vacuum distillation was 15 mPa·sec. There was no adhesion to the wall surface in the distillation tank. The yield of the resin particle dispersion was 99.5%, and the amount of the distillate recovered (the amount of the distillate recovered after returning to normal pressure) relative to the mass at the start of vacuum distillation was the amount of "mass at the start of vacuum distillation × 0.59".

[0139] <Examples 2 to 27> According to Table 1, except that the type of the phase inversion emulsion and the conditions of vacuum distillation were changed, an amorphous polyester resin particle dispersion was obtained in the same manner as in Example 1.

[0140] <Examples 28 to 31> Except that the recovery amount at which the residual organic solvent concentration by gas chromatography became that in Table 1 was changed, an amorphous polyester resin particle dispersion was obtained in the same manner as in Example 1.

[0141] <Comparative Example 1> An amorphous polyester resin particle dispersion was obtained in the same manner as in Example 1, except that water was not added to the phase inversion emulsion during vacuum distillation.

[0142] <Evaluation> (Yield of resin particle dispersion) The yield of the resin particle dispersion was calculated from the mass of the resin particle dispersion after vacuum distillation and the actually measured solid content concentration, and evaluated according to the following criteria. A〇: 99% or more B△: 98% or more C×: Less than 98%

[0143] (Adhesion to the wall surface of the distillation tank) The wall surface of the distillation tank was visually observed, and the adhesion state of the resin was evaluated according to the following criteria. A〇: No resin adhesion B△: Slight resin adhesion was confirmed C×: Resin adhesion requiring equipment cleaning was confirmed

[0144] (Distillate recovery amount) The distillate was sampled in the middle of the pipeline, and the distillate recovery amount at which the residual organic solvent concentration was less than 1% was determined by gas chromatography analysis according to the following criteria. A〇: The distillate recovery amount is the mass at the start of vacuum distillation × 0.59 B△: The distillate recovery amount is the mass at the start of vacuum distillation × 0.59 to 0.6 (exceeding) C×: The distillate recovery amount exceeds the mass at the start of vacuum distillation × 0.6

[0145]

Table 1-1

[0146]

Table 1-2

[0147] From the above results, it can be seen that in the method for producing the resin particle dispersion of this example, compared with the comparative example, the decrease in the yield due to the adhesion of the resin to the inner wall surface of the distillation tank is suppressed.

Explanation of symbols

[0148] 100 Emulsifying device 104 Heating section 106 Stirring section 108 Supply line 110 Pump 112 Emulsion transfer line 200 Vacuum distillation apparatus 202 Distillation tank 204 Heating section 204A Heat transfer surface 206 Stirring section 206A Stirring shaft 206B Trough-shaped stirring blade 208 Aqueous medium supply line 300 Distillate recovery apparatus 302 Distillation tank 302 Recovery tank 304 Solvent discharge line 306 Condenser 308 Vacuum pump

Claims

1. A step of preparing a phase inversion emulsion in which a resin is phase-inverted and emulsified using an organic solvent and an aqueous medium; A step of removing the organic solvent from the phase inversion emulsion by vacuum distillation; having A distillation tank in which the phase inversion emulsion is contained; A heating unit that flows a heating fluid inside to heat the tank wall of the distillation tank; A stirring unit provided in the distillation tank, comprising a stirring shaft and one or a plurality of gutter-shaped stirring blades attached to the stirring shaft that stir the phase inversion emulsion by rotation and pump up the phase inversion emulsion to form a liquid film of the phase inversion emulsion on the heat transfer surface of the distillation tank above the liquid level of the phase inversion emulsion; Performing the vacuum distillation using a vacuum distillation apparatus comprising and, during the vacuum distillation, adding an aqueous medium to the phase inversion emulsion contained in the distillation tank, The relationship between the installation angle θ [°] of the gutter-shaped stirring blade with respect to the stirring shaft, the rotational speed N [rpm] of the stirring shaft, the inner diameter D [m] of the distillation tank, and the maximum diameter d [m] of the rotation locus of the gutter-shaped stirring blade satisfies the following formulas 1 to 4, A method for producing a resin particle dispersion. Formula 1: 10 ≤ θ ≤ 45 Formula 2: 14 ≤ N·sinθ ≤ 60 Formula 3: 0.4 ≤ D ≤ 5 Formula 4: 0.75 ≤ d / D ≤ 0.95

2. The method for producing a resin particle dispersion according to claim 1, wherein during the vacuum distillation, the aqueous medium is added to the phase inversion emulsion contained in the distillation tank so that the solid content concentration of the phase inversion emulsion is maintained in the range of 25% by mass to 45% by mass.

3. The method for producing a resin particle dispersion according to claim 1 or claim 2, wherein during the vacuum distillation, the aqueous medium is added to the phase inversion emulsion contained in the distillation tank so that the maximum viscosity of the phase inversion emulsion is maintained in the range of 30 mPa·sec or less.

4. When adding the aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation, the distillation recovery rate per unit heat transfer area of the distillation tank is 60 kg / h / m ２ The method for producing a resin particle dispersion according to any one of claims 1 to 3, which is as follows.

5. When adding the aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation, the temperature T1 of the phase-inverted emulsion is 25°C or higher and (the glass transition temperature Tg of the resin - 1°C) or lower, the temperature T2 of the heating fluid flowing inside the heating unit is 95°C or lower, and the relationship between T1 and T2 is T1 < T2. The method for producing a resin particle dispersion according to any one of claims 1 to 4.

6. The temperature T3 of the aqueous medium added to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation is (the glass transition temperature Tg of the resin - 1°C) or lower. The method for producing a resin particle dispersion according to any one of claims 1 to 5.

7. The temperature T3 of the aqueous medium is (the glass transition temperature Tg of the resin - 30°C) or higher and (the glass transition temperature Tg of the resin - 1°C) or lower, and 5°C or higher. The method for producing a resin particle dispersion according to claim 6.

8. The addition rate of the aqueous medium added to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation is an addition rate that varies within the range of the temperature T1 ± 5 of the phase-inverted emulsion when adding the aqueous medium to the phase-inverted emulsion contained in the distillation tank during the vacuum distillation. The method for producing a resin particle dispersion according to any one of claims 1 to 7.

9. Manufacture the phase-inverted emulsion in an emulsification tank, transfer it from the emulsification tank to the distillation tank, and perform the vacuum distillation. The method for producing a resin particle dispersion according to any one of claims 1 to 8.

10. The resin is a resin having a polar group. The method for producing a resin particle dispersion according to any one of claims 1 to 9.

11. The method for producing a resin particle dispersion according to claim 10, wherein the resin having the polar group is a resin having an acid value.

12. The method for producing a resin particle dispersion according to any one of claims 1 to 11, wherein the content of the residual organic solvent in the resin particle dispersion is 25 ppm or more and 3000 ppm or less.

13. The method for producing a resin particle dispersion according to any one of claims 1 to 12, for producing a resin particle dispersion for toner.

14. A step of obtaining a resin particle dispersion by the method for producing a resin particle dispersion according to any one of claims 1 to 13, a step of aggregating at least the resin particles in a dispersion containing the resin particles of the obtained resin particle dispersion to form aggregated particles, a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and unite the aggregated particles to form toner particles, A method for producing a toner for electrostatic charge image development having the above steps.

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