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 manufacturing a resin particle dispersion which reduces an amount of a distillate to be discarded.SOLUTION: A method for manufacturing a resin particle dispersion, using an apparatus for manufacturing a resin particle dispersion including two or more resin particle dispersion manufacturing lines, and recycle distillate storage tanks A for collecting and storing a distillate collected in at least one distillate correction tank A among distillates collected in the plurality of distillate collection tanks in each of the two or more resin particle dispersion manufacturing lines, includes sending the distillate from the recycle distillate storage tank A to an emulsification tank of at least the one manufacturing line among the two or more resin particle dispersion manufacturing lines, and recycling the distillate for manufacture of a phase inversion emulsification liquid.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] For example, Patent Document 1 discloses "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, and 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 dispersion tank for containing a resin aqueous dispersion containing a resin, water, and an organic solvent, a recovery means for recovering at least a part of the water and the organic solvent from the resin aqueous dispersion, a conductivity measurement means for measuring the conductivity of a recovered liquid containing at least one of the recovered water and organic solvent, a separation means for separating the recovered liquid, a weight measurement means for measuring the weight of the separated separated liquid, a control means for controlling the separation means according to the measured conductivity and weight, and a supply means for supplying a separated liquid mainly composed of water as added water during the production of the resin aqueous dispersion."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a method for producing a resin particle dispersion that reduces the amount of distillate to be discarded compared to the case where the distillate is directly sent from the distillate recovery tank to the emulsification tank, sent to the phase inversion emulsion, and reused for the production of the phase inversion emulsion, in a method for producing a resin particle dispersion using two or more production lines of resin particle dispersions, each having an emulsification tank for phase inversion emulsification of a resin using two or more organic solvents and an aqueous medium to obtain a phase inversion emulsion, a distillation tank for removing the organic solvent from the phase inversion emulsion by vacuum distillation to obtain a resin particle dispersion, and a plurality of distillate recovery tanks for recovering the distillate generated by the vacuum distillation for each target distillate composition.

Means for Solving the Problems

[0006] Specific means for solving the above problems include the following aspects. <1> An emulsification tank for phase inversion emulsification of a resin using two or more organic solvents and an aqueous medium to obtain a phase inversion emulsion, a distillation tank for removing the organic solvent from the phase inversion emulsion by vacuum distillation to obtain a resin particle dispersion, and a plurality of distillate recovery tanks for recovering the distillate generated by the vacuum distillation for each target distillate composition, in two or more production lines of resin particle dispersions; In each of the two or more production lines of resin particle dispersions, a reuse distillate storage tank A for collecting and storing the distillate recovered in at least one distillate recovery tank A among the distillates recovered in the plurality of distillate recovery tanks; using a production apparatus for resin particle dispersions comprising; A method for producing a resin particle dispersion, wherein the distillate is sent from the reuse distillate storage tank A to the emulsification tank of at least one of the two or more production lines of resin particle dispersions and reused for the production of the phase inversion emulsion. <2> Determine the amount of the reused residual liquid from the mixing ratios of two or more organic solvents in the residual liquid stored in the reused residual liquid storage tank A and the mixing ratios of two or more organic solvents during the production of the phase inversion emulsion. Then, send the residual liquid in the determined amount of the reused residual liquid from the reused residual liquid storage tank A to the emulsification tank of at least one of the production lines for producing the two or more resin particle dispersions, and reuse it in the production of the phase inversion emulsion. The method for producing a resin particle dispersion according to <1>. <3> Analyze the composition of the residual liquid by at least one measurement selected from the group consisting of weight measurement, gas chromatography measurement, liquid chromatography measurement, infrared spectroscopy measurement, ultrasonic propagation velocity measurement, neutralization titration, specific gravity measurement, and conductivity measurement of the residual liquid. For each target residual liquid composition, change the residual liquid recovery tank for recovering the residual liquid. The method for producing a resin particle dispersion according to <1> or <2>. <4> Calculate the mixing ratios of two or more organic solvents in the residual liquid stored in the reused residual liquid storage tank A from the mixing ratios and amounts of two or more organic solvents during the production of the phase inversion emulsion, the amount of the residual liquid recovered in the residual liquid recovery tank A, and the amount of the residual liquid stored in the reused residual liquid storage tank A. The method for producing a resin particle dispersion according to any one of <1> to <3>. <5> Measure the mixing ratios of two or more organic solvents in the residual liquid stored in the reused residual liquid storage tank A by at least one measurement selected from the group consisting of gas chromatography measurement, liquid chromatography measurement, infrared spectroscopy measurement, ultrasonic propagation velocity measurement, neutralization titration, specific gravity measurement, and conductivity measurement of the residual liquid stored in the reused residual liquid storage tank A. The method for producing a resin particle dispersion according to any one of <1> to <3>. <6> Store in the reused residual liquid storage tank A a residual liquid having an organic solvent content of 30% by mass or more. The method for producing a resin particle dispersion according to any one of <1> to <5>. <7> Send the residual liquid having an organic solvent content of 30% by mass or more stored in the reused residual liquid storage tank A to the emulsification tank as an organic solvent. The method for producing a resin particle dispersion according to <6>. <8> In the production apparatus of the resin particle dispersion liquid, in each production line of the two or more resin particle dispersion liquids, among the retained liquids recovered in the plurality of retained liquid recovery tanks, the retained liquid recovered in at least one retained liquid recovery tank B is collected and stored in a reused retained liquid storage tank B. The reused retained liquid storage tank B stores a retained liquid having an aqueous medium content of 80% by mass or more. A method for producing a resin particle dispersion liquid according to any one of <6> or <7>, wherein the retained liquid having an aqueous medium content of 80% by mass or more is sent from the reused retained liquid storage tank B to the emulsification tank of at least one production line among the two or more resin particle dispersion liquid production lines and reused for the production of the phase inversion emulsion. <9> A method for producing a resin particle dispersion liquid according to <8>, wherein the retained liquid having an aqueous medium content of 80% by mass or more stored in the reused retained liquid storage tank B is phase inversion emulsified with two or more organic solvents and an aqueous medium, and then sent to the emulsification tank. <10> In the production lines of the two or more resin particle dispersion liquids, at least one of the types of the two or more organic resins, the mixing ratio of the two or more organic resins, and the type of the resin is changed mutually, or the types of the two or more organic resins, the mixing ratio of the two or more organic resins, and the type of the resin are made the same to produce a resin particle dispersion liquid. The method for producing a resin particle dispersion liquid according to any one of <1> to <9>. <11> In each production line of the two or more resin particle dispersion liquids, for each production cycle, at least one of the types of the two or more organic resins, the mixing ratio of the two or more organic resins, and the type of the resin is changed, or the types of the two or more organic resins, the mixing ratio of the two or more organic resins, and the type of the resin are made the same to produce a resin particle dispersion liquid. The method for producing a resin particle dispersion liquid according to any one of <1> to <10>. <12> 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 <11>, a step of aggregating at least the resin particles 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 manufacturing an electrostatic charge image developing toner having the same. <13> An electrostatic charge image developing toner having toner particles obtained by the method for manufacturing an electrostatic charge image developing toner according to <12>.

Advantages of the Invention

[0007] According to the invention according to <1>, <2>, <3>, <4>, <5>, <11> or <11>, an emulsifying tank for obtaining a phase inversion emulsion by phase inversion emulsification of a resin using two or more organic solvents and an aqueous medium, a distillation tank for removing an organic solvent from the phase inversion emulsion by vacuum distillation to obtain a resin particle dispersion, and a plurality of residue recovery tanks for recovering the residue generated by vacuum distillation for each target residue composition, in a method for manufacturing a resin particle dispersion using two or more manufacturing lines for the resin particle dispersion, when directly feeding the residue from the residue recovery tank to the emulsifying tank and then feeding it to the phase inversion emulsion for reuse in the production of the phase inversion emulsion, a method for manufacturing a resin particle dispersion is provided that reduces the amount of residue to be discarded compared to the case of discarding it.

[0008] According to the invention according to <6> or <7>, a method for manufacturing a resin particle dispersion is provided that reduces the amount of residue to be discarded compared to the case of storing a residue having an organic solvent content of less than 30% by mass in a reuse residue storage tank A.

[0009] According to the invention according to <8> or <9>, a method for manufacturing a resin particle dispersion is provided that reduces the amount of residue to be discarded compared to the case of storing a residue having an aqueous medium content of less than 80% by mass in a reuse residue storage tank B.

[0010] According to the invention according to <15> or <16>, an emulsifying tank for obtaining a phase-inverted emulsion by phase-inverting emulsification of a resin using two or more organic solvents and an aqueous medium, a distillation tank for removing the organic solvent from the phase-inverted emulsion by vacuum distillation to obtain a resin particle dispersion, and a plurality of distillate recovery tanks for recovering the distillate generated by vacuum distillation for each target distillate composition. In the method for producing a resin particle dispersion using two or more production lines having the above, when applying the method for producing a resin particle dispersion in which the distillate is directly sent from the distillate recovery tank to the emulsifying tank and then sent to the phase-inverted emulsion for reuse in the production of the phase-inverted emulsion, compared to the case where the amount of distillate to be discarded is reduced, a method for producing a toner for electrostatic charge image development or a toner for electrostatic charge image development is provided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments which are an example of the present invention will be described. These descriptions and examples illustrate the present invention and do not limit the present invention.

[0013] In this specification, the 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 step by step 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 ranges described in other step-by-step 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.

[0014] In this specification, the term "step" includes not only an independent step but also the step even when it cannot be clearly distinguished from other steps as long as the intended purpose of the step is achieved.

[0015] 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 drawing are conceptual, and the relative size relationships between the members are not limited thereto.

[0016] In this specification, each component may contain a plurality of corresponding substances. When referring to the amount of each component in the 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.

[0017] In this specification, the "toner for electrostatic charge image development" is also simply referred to as "toner".

[0018] <Method for Producing Resin Particle Dispersion> The method for producing a resin particle dispersion according to this embodiment is An emulsification tank that uses two or more organic solvents and an aqueous medium to phase-invert emulsify a resin to obtain a phase-inverted emulsion, a distillation tank for removing the organic solvent from the phase-inverted emulsion by vacuum distillation to obtain a resin particle dispersion, and a plurality of distillate recovery tanks for recovering the distillate generated by vacuum distillation for each target distillate composition, and two or more resin particle dispersion production lines having the same; In each of the two or more resin particle dispersion production lines, among the distillates recovered in the plurality of distillate recovery tanks, a reuse distillate storage tank A for collecting and storing the distillates recovered in at least one distillate recovery tank A; A manufacturing apparatus for a resin particle dispersion liquid is used. In the method for manufacturing a resin particle dispersion liquid according to the present embodiment, the retained liquid is fed from the reused retained liquid storage tank A to the emulsifying tank of at least one of two or more manufacturing lines for the resin particle dispersion liquid, and reused for the production of the phase inversion emulsion.

[0019] Here, conventionally, in the method for manufacturing a resin particle dispersion liquid using the phase inversion emulsification method, when removing an organic solvent from the phase inversion emulsion by vacuum distillation in a distillation tank to obtain a resin particle dispersion liquid, the retained liquid generated by the vacuum distillation is recovered in a retained liquid recovery tank. And a part of the retained liquid recovered in the retained liquid recovery tank is reused for the production of the phase inversion emulsion.

[0020] However, when manufacturing a resin particle dispersion liquid using a manufacturing apparatus equipped with two or more manufacturing lines for the resin particle dispersion liquid, the reuse rate of the retained liquid decreases, and the amount of discarded retained liquid increases. This is because the ratio and amount of the organic solvent required for phase inversion emulsification vary greatly depending on the type and physical properties of the resin.

[0021] On the other hand, in the method for manufacturing a resin particle dispersion liquid according to the present embodiment, in each of two or more manufacturing lines for the resin particle dispersion liquid, among the retained liquids recovered in a plurality of retained liquid recovery tanks, the retained liquid recovered in at least one retained liquid recovery tank A is collected and stored in the reused retained liquid storage tank A. And from the reused retained liquid storage tank A, the retained liquid is fed to the emulsifying tank of at least one of two or more manufacturing lines for the resin particle dispersion liquid, and reused for the production of the phase inversion emulsion. That is, in the reused retained liquid storage tank A, the retained liquids recovered in the retained liquid recovery tanks in each of two or more manufacturing lines for the resin particle dispersion liquid are mixed and stored. Thereby, the mixing ratio of two or more kinds of organic solvents of the retained liquid stored in the reused retained liquid storage tank A is equalized. Therefore, even when a resin particle dispersion liquid is irregularly manufactured using resins with different ratios of two or more kinds of organic solvents, fluctuations in the ratio of two or more kinds of organic solvents of the retained liquid stored in the reused retained liquid storage tank A can be suppressed. Thus, the reuse rate of the retained liquid can be maximized, and the amount of discarded retained liquid can be reduced.

[0022] From the above, in the method for producing the resin particle dispersion according to the present embodiment, the amount of the residual liquid to be discarded can be reduced. In addition, since the reuse rate of the residual liquid can be maximized, it is also possible to reduce the amount of the organic solvent newly used.

[0023] Hereinafter, the details of the method for producing the resin particle dispersion according to the present embodiment will be described.

[0024] (Manufacturing Apparatus for Resin Particle Dispersion) First, an overview of the manufacturing apparatus for the resin particle dispersion used in the method for producing the 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 for the resin particle dispersion used in the method for producing the resin particle dispersion according to the present embodiment.

[0025] The manufacturing apparatus shown in FIG. 1 includes a first production line 100A for the resin particle dispersion, a second production line 100B for the resin particle dispersion, a first reuse residual liquid storage tank 200A (an example of the reuse residual liquid storage tank A), and a second reuse residual liquid storage tank 200B (an example of the reuse residual liquid storage tank B). Note that the number of production lines is not limited to two, and may be three or more.

[0026] The first and second production lines 100A and 100B include emulsifying tanks 10A and 10B, distillation tanks 20A and 20B, first residual liquid recovery tanks 30A and 30B (an example of the residual liquid recovery tank A), and second residual liquid recovery tanks 31A and 31B (an example of the residual liquid recovery tank B).

[0027] The emulsifying tanks 10A and 10B are emulsifying tanks that obtain an inverse-phase emulsion by inversely emulsifying a resin using two or more organic solvents and an aqueous medium. Inside the emulsifying tanks 10A and 10B, stirrers 11A and 11B for stirring the raw materials and inversely emulsifying the resin are provided.

[0028] Connected to the emulsifying tanks 10A and 10B are a resin supply pipe 41A and 41B, a neutralizing agent supply pipe 43A and 43B, an organic solvent supply pipe 45A and 45B, and an aqueous medium supply pipe 47A and 47B for supplying a resin, a neutralizing agent, an organic solvent, and an aqueous medium to the emulsifying tanks 10A and 10B, respectively. The resin supply pipes 41A and 41B, the neutralizer supply pipes 43A and 43B, the organic solvent supply pipes 45A and 45B, and the aqueous medium supply pipes 47A and 47B are respectively connected to the resin storage tanks 40A and 40B, the neutralizer storage tanks 42A and 42B, the organic solvent storage tanks 44A and 44B, and the aqueous medium storage tanks 46A and 46B. Here, the organic solvent storage tanks 44A and 44B store a mixed organic solvent obtained by mixing two or more types of organic solvents. However, the emulsification tanks 10A and 10B may be connected to the organic solvent supply pipes connected to the organic solvent storage tanks that store two or more types of organic solvents respectively, and each organic solvent may be supplied to the emulsification tanks 10A and 10B respectively.

[0029] Although not shown in the drawings, the emulsification tanks 10A and 10B are provided with well-known members for producing a phase-inverted emulsion, such as a heating unit (so-called jacket) for heating the tank walls of the emulsification tanks 10A and 10B.

[0030] The distillation tanks 20A and 20B are distillation tanks for removing organic solvents from the phase-inverted emulsion by vacuum distillation to obtain a resin particle dispersion. Inside the distillation tanks 20A and 20B, stirrers 21A and 21B for stirring the phase-inverted emulsion are provided.

[0031] Although not shown in the drawings, the distillation tanks 20A and 20B are provided with well-known members for vacuum distilling the phase-inverted emulsion, such as a heating unit (so-called jacket) for heating the tank walls of the distillation tanks 20A and 20B.

[0032] The first distillate recovery tanks 30A and 30B, and the second distillate recovery tanks 31A and 31B are distillate recovery tanks for recovering the distillate generated by vacuum distillation for each distillate composition. Note that the number of distillate recovery tanks is not limited to two, and there may be three or more.

[0033] The first recycled distillate storage tank 200A is a storage tank for collecting and storing the distillate recovered in the first distillate recovery tanks 30A and 30B of the first and second production lines 100A and 100B. The second reuse retention liquid storage tank 200B is a storage tank that collects and stores the retention liquid recovered in the second retention liquid recovery tanks 31A and 31B of the first and second production lines 100A and 100B. Note that the reuse retention liquid storage tank is not limited to two, and may be one, or three or more.

[0034] Here, the emulsification tanks 10A and 10B and the distillation tanks 20A and 20B are connected by emulsion liquid feed pipes 50A and 50B via pumps 51A and 51B.

[0035] The distillation tanks 20A and 20B, the first retention liquid recovery tanks 30A and 30B, and the second retention liquid recovery tanks 31A and 31B are connected by solvent discharge pipes 52A and 52B via valves 53A and 53B. Specifically, the solvent discharge pipes 52A and 52B branch in the middle of the path, connecting the distillation tanks 20A and 20B to the first retention liquid recovery tanks 30A and 30B, and connecting the distillation tanks 20A and 20B to the second retention liquid recovery tanks 31A and 31B.

[0036] The solvent discharge pipes 52A and 52B are provided with condensers 54A and 54B that condense the organic solvent and the aqueous medium that evaporate from the phase-inverted emulsion liquid contained in the distillation tanks 20A and 20B by vacuum distillation into retention liquid in the middle of the path, and analysis units 55A and 55B for analyzing the retention liquid composition of the retention liquid.

[0037] The first retention liquid recovery tanks 30A and 30B and the first reuse retention liquid storage tank 200A are connected by a first retention liquid feed pipe 201A. Specifically, the first retention liquid feed pipe 201A branches in the middle of the path, connecting the first retention liquid recovery tank 30A to the first reuse retention liquid storage tank 200A, and connecting the first retention liquid recovery tank 30B to the first reuse retention liquid storage tank 200A.

[0038] The second retention liquid recovery tanks 31A and 31B and the second reuse retention liquid storage tank 200B are connected by a second retention liquid feed pipe 201B. Specifically, the second retention liquid feed pipe 201B branches in the middle of the path, connecting the second retention liquid recovery tank 31A to the second reuse retention liquid storage tank 200B, and connecting the second retention liquid recovery tank 31B to the second reuse retention liquid storage tank 200B.

[0039] The first reuse retention liquid storage tank 200A and the emulsification tanks 10A and 10B are connected by a first storage retention liquid feed pipe 203A via a pump 202A and a valve 204A. Specifically, the first storage retention liquid feed pipe 203A branches in the middle of the path to connect the first reuse retention liquid storage tank 200A and the emulsification tank 10A, and to connect the first reuse retention liquid storage tank 200A and the emulsification tank 10B. The first storage retention liquid feed pipe 203A is connected in the middle of the paths of the organic solvent supply pipes 45A and 45B.

[0040] The second reuse retention liquid storage tank 200B and the emulsification tanks 10A and 10B are connected by a second storage retention liquid feed pipe 203B via a pump 202B and a valve 204B. Specifically, the second storage retention liquid feed pipe 203B branches in the middle of the path to connect the second reuse retention liquid storage tank 200B and the emulsification tank 10A, and to connect the second reuse retention liquid storage tank 200B and the emulsification tank 40B. The second storage retention liquid feed pipe 203B is connected in the middle of the paths of the aqueous medium supply pipes 47A and 47B.

[0041] Next, the steps of the method for producing the resin particle dispersion according to the present embodiment will be described.

[0042] In the method for producing the resin particle dispersion according to the present embodiment, in each of the first and second production lines 100A and 100B, the following phase inversion emulsion production step and solvent removal step are carried out to obtain a resin particle dispersion. Then, through the retention liquid recovery step and the retention liquid reuse step, the retention liquid is reused.

[0043] (Phase inversion emulsion production step) In the phase inversion emulsion production step, in the emulsification tanks 10A and 10B, a phase inversion emulsion obtained by phase inversion emulsifying a resin using an organic solvent and an aqueous medium is obtained. The phase inversion emulsification method is a method in which a resin is converted from W / O to O / W (so-called phase inversion), and the oil-phase dispersion is made into a discontinuous phase, and the resin is dispersed in a particulate form in an aqueous medium by introducing an aqueous medium (i.e., W phase) into an oil-phase dispersion (i.e., a resin solution that becomes the O phase) that is a continuous phase in which the resin is dissolved in an organic solvent in which the resin is soluble.

[0044] Specifically, for example, a mixed organic solvent obtained by mixing two or more organic solvents is supplied from organic solvent storage tanks 44A and 44B to emulsification tanks 10A and 10B through organic solvent supply pipes 45A and 45B. Next, while mixing the mixed organic solvent with stirrers 11A and 11B, a resin is supplied from resin storage tanks 40A and 40B to emulsification tanks 10A and 10B through resin supply pipes 41A and 41B. Thereby, the resin is dissolved in the mixed organic solvent. Next, a neutralizing agent is supplied from neutralizing agent storage tanks 42A and 42B to emulsification tanks 10A and 10B through neutralizing agent supply pipes 43A and 43B. Thereby, the resin is neutralized. Next, an aqueous medium is supplied from aqueous medium storage tanks 46A and 46B to emulsification tanks 10A and 10B through aqueous medium supply pipes 47A and 47B. Then, by stirring and heating the mixed liquid in emulsification tanks 10A and 10B, the resin is phase-inversion emulsified to obtain a phase-inversion emulsion.

[0045] Here, after supplying the mixed organic solvent and the neutralizing agent to emulsification tanks 10A and 10B, the resin may be supplied. Alternatively, the mixed organic solvent may be supplied to emulsification tanks 10A and 10B after first supplying the resin.

[0046] Next, the phase-inversion emulsion is sent from emulsification tanks 10A and 10B to distillation tanks 20A and 20B through emulsion liquid transfer pipes 50A and 50B by pumps 51A and 51B.

[0047] (Organic solvent removal step) In the organic solvent removal step, the organic solvent is removed from the phase-inversion emulsion by vacuum distillation in distillation tanks 20A and 20B. Under reduced pressure distillation, while stirring and heating, the organic solvent and the aqueous medium are evaporated to remove the organic solvent from the inverse phase emulsion, thereby obtaining a resin particle dispersion.

[0048] In the reduced pressure distillation method, a well-known method such as a method of performing reduced pressure distillation while bubbling an inert gas using a reduced pressure distillation tank equipped with a stirrer, or a method of performing reduced pressure distillation while forming a liquid film on the heat transfer surface of the tank above the liquid level by assembling the inverse phase emulsion in the reduced pressure distillation tank upward, which is called a wall wetter, can be adopted.

[0049] (Residual liquid recovery step) In the distillation tanks 20A and 20B, during reduced pressure distillation, the evaporated organic solvent and the aqueous medium are condensed by the condensers 54A and 54B through the solvent discharge pipes 52A and 52B and recovered as residual liquid into the first residual liquid recovery tanks 30A and 30B and the second residual liquid recovery tanks 31A and 31B.

[0050] Here, the composition of the residual liquid is such that at the start of reduced pressure distillation, the organic solvent concentration is high and the aqueous medium concentration is low. As the reduced pressure distillation continues, the organic solvent concentration becomes low and the aqueous medium concentration becomes high. Then, when the organic solvent concentration (i.e., the residual organic solvent concentration) in the inverse phase emulsion in the distillation tanks 20A and 20B reaches below the target concentration, the reduced pressure distillation is terminated.

[0051] Therefore, for example, at the start of reduced pressure distillation, the residual liquid is recovered in the first residual liquid recovery tanks 30A and 30B, and when the aqueous medium concentration of the residual liquid reaches the target concentration (in other words, when the organic solvent concentration of the residual liquid decreases to the target concentration), the valves 53A and 53B are operated to recover the residual liquid in the second residual liquid recovery tanks 31A and 31B. That is, for each target residual liquid composition, the residual liquid recovery tank for recovering the residual liquid is changed. Examples of the target aqueous medium concentration of the residual liquid include 80% by mass, 85% by mass, 90% by mass, or 95% by mass. Examples of the second residual liquid recovery tanks 31A and 31B include recovering a residual liquid having an aqueous medium concentration of 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more. On the one hand, it can be exemplified that the liquid residues with an organic solvent concentration of 30% by mass or more, 40% by mass or more, 45% by mass or more, or 50% by mass or more are recovered in the first liquid residue recovery tanks 30A and 30B.

[0052] Note that the number of liquid residue recovery tanks is not limited to two, and three or more may be provided. When three or more liquid residue recovery tanks are provided, liquid residues with three or more different aqueous medium concentrations (or organic solvent concentrations) can be recovered in the liquid residue recovery tanks respectively.

[0053] Here, the composition of the liquid residue (specifically, the aqueous medium concentration or organic solvent concentration of the liquid residue) is analyzed by the analysis units 55A and 55B. According to the analysis results, the valves 53A and 53B are operated, and the liquid residue recovery tank for recovering the liquid residue is changed for each target liquid residue composition.

[0054] The analysis units 55A and 55B can analyze the composition of the liquid residue. The analysis units 55A and 55B are equipped with various sensors such as conductivity meters. However, the liquid residue may be sampled from the solvent discharge pipes 52A and 52B, and the composition of the sampled liquid residue may be analyzed. The analysis can be exemplified by at least one measurement selected from the group consisting of gas chromatography measurement, liquid chromatography measurement, infrared spectroscopy measurement, ultrasonic propagation velocity measurement, neutralization titration, specific gravity measurement, and conductivity measurement. In addition, the degree of change in the composition of the liquid residue during vacuum distillation can be known experimentally in advance. Therefore, the composition of the liquid residue can also be determined by measuring the weight of the liquid residue. The weight of the liquid residue can be measured, for example, by providing a weighing scale in the first liquid residue recovery tanks 30A and 30B and using the weighing scale. That is, for example, the composition of the liquid residue is analyzed by at least one measurement selected from the group consisting of weight measurement, gas chromatography measurement, liquid chromatography measurement, infrared spectroscopy measurement, ultrasonic propagation velocity measurement, neutralization titration, specific gravity measurement, and conductivity measurement of the liquid residue, and the liquid residue recovery tank for recovering the liquid residue can be changed for each target liquid residue composition.

[0055] (Reuse process) - First reuse liquid residue storage tank 200A- The retained liquid recovered by the first retained liquid recovery tanks 30A and 30B is fed through the first retained liquid feed pipe 201A to the first reused retained liquid storage tank 200A, where it is mixed and stored.

[0056] The retained liquid stored in the first reused retained liquid storage tank 200A drives the pumps 202A and 202B and the valves 204A and 204B, and is fed through the first stored liquid feed pipe 203A to the emulsification tanks 10A and 10B for reuse in the production of the phase inversion emulsion. Note that the retained liquid may be fed to one of the emulsification tanks 10A and 10B for reuse in the production of the phase inversion emulsion in either of the emulsification tanks 10A and 10B.

[0057] The first reused retained liquid storage tank 200A preferably stores the retained liquid with an organic solvent content of 30% by mass or more. Then, the retained liquid with an organic solvent content of 30% by mass or more stored in the first reused retained liquid storage tank 200A is fed to the emulsification tanks 10A and 10B as an organic solvent. Thereby, the reuse rate of the retained liquid as an organic solvent is increased, and the amount of discarded retained liquid is reduced. Also, the amount of newly used organic solvent is reduced. The organic solvent content of the retained liquid stored in the first reused retained liquid storage tank 200A is adjusted according to the organic solvent content of the retained liquid recovered by the first retained liquid recovery tanks 30A and 30B and the mixing ratio.

[0058] From the viewpoints of improving the reuse rate of the retained liquid and reducing the amount of discarded retained liquid, the first reused retained liquid storage tank 200A preferably stores the retained liquid with an organic solvent content of preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more. Note that the upper limit of the organic solvent content of the retained liquid stored in the first reused retained liquid storage tank 200A is, for example, 100% by mass or less.

[0059] Here, the reuse retained liquid amount (that is, the feed amount) of the retained liquid stored in the first reused retained liquid storage tank 200A is preferably determined from the mixing ratio of two or more organic solvents in the retained liquid stored in the first reused retained liquid storage tank 200A and the mixing ratio of two or more organic solvents during the production of the phase inversion emulsion. Specifically, the reuse retained liquid amount of the retained liquid is preferably determined as follows. After determining the respective amounts of organic solvents according to the type and physical properties of the resin, multiply the respective organic solvent concentrations and any desired retention liquid amounts of the retention liquid in the first reuse retention liquid storage tank 200A, and set the retention liquid amount when reaching the amount of organic solvent determined for any of the organic solvents as the reuse retention liquid amount. Thereby, the reuse rate of the retention liquid is increased, and the amount of waste liquid of the retention liquid is further reduced.

[0060] The mixing ratio of two or more organic solvents in the retention liquid stored in the first reuse retention liquid storage tank 200A can be calculated from the mixing ratio and amount of two or more organic solvents during the production of the phase inversion emulsion, the amount of retention liquid recovered in the first retention liquid recovery tank A, and the amount of retention liquid stored in the first reuse retention liquid storage tank 200A. Specifically, the mixing ratio of two or more organic solvents in the retention liquid stored in the first reuse retention liquid storage tank 200A can be calculated as follows. Integrate the respective amounts of organic solvents determined in each of the first and second production lines 100A and 100B, and divide the integrated value of the respective amounts of organic solvents by all the organic solvents to calculate the organic solvent mixing ratio. At this time, by considering the recovery yield of the organic solvents recovered by the condensers 54A and 54B measured in advance, the organic solvent mixing ratio can be calculated with higher accuracy.

[0061] Also, the mixing ratio of two or more organic solvents in the retention liquid stored in the first reuse retention liquid storage tank 200A may be measured by at least one selected from the group consisting of gas chromatography measurement, liquid chromatography measurement, infrared spectroscopy measurement, ultrasonic propagation velocity measurement, neutralization titration, specific gravity measurement, and conductivity measurement of the retention liquid stored in the first reuse retention liquid storage tank 200A.

[0062] -Second Reuse Retention Liquid Storage Tank 200B- The retention liquid recovered in the second retention liquid recovery tanks 31A and 31B is sent through the second retention liquid feed pipe 201B to the second reuse retention liquid storage tank 200B, mixed, and stored.

[0063] The liquid retained in the second reuse liquid storage tank 200B is pumped through the second retained liquid feed pipe 203B by driving pumps 202A and 202B and valves 204A and 204B, and fed to the emulsification tanks 10A and 10B for reuse in the production of the phase inversion emulsion. Note that the liquid may be fed to one of the emulsification tanks 10A and 10B and reused in the production of the phase inversion emulsion in either of the emulsification tanks 10A and 10B.

[0064] It is preferable to store in the second reuse liquid storage tank 200B a retained liquid having an aqueous medium content of 80% by mass or more. Then, the retained liquid having an aqueous medium content of 80% by mass or more stored in the second reuse liquid storage tank 200B is fed to the emulsification tanks 10A and 10B as the aqueous medium. Thereby, the reuse rate of the retained liquid as the aqueous medium is increased, and the amount of discarded retained liquid is reduced. The amount of the aqueous medium in the retained liquid stored in the second reuse liquid storage tank 200B is adjusted according to the amount of the aqueous medium in the retained liquid recovered in the second retained liquid recovery tanks 31A and 31B and the mixing ratio.

[0065] From the viewpoints of improving the reuse rate of the retained liquid and reducing the amount of discarded retained liquid, it is preferable to store in the second reuse liquid storage tank 200B a retained liquid having an aqueous medium content of preferably 85% by mass or more, more preferably 90% by mass, and still more preferably 95% by mass or more. Note that the upper limit of the amount of the aqueous medium in the retained liquid stored in the second reuse liquid storage tank 200B is, for example, 100% by mass or less.

[0066] Here, the retained liquid having an aqueous medium content of 80% by mass or more stored in the second reuse liquid storage tank 200B may be fed to the emulsification tanks 10A and 10B after phase inversion emulsification of the resin using two or more organic solvents and the aqueous medium. By adding the retained liquid having an aqueous medium content of 80% by mass or more stored in the second reuse liquid storage tank 200B as a supplementary aqueous medium to the phase inversion emulsion after phase inversion emulsification of the resin, the retained liquid is reused to reduce the amount of discarded retained liquid, while suppressing deterioration of the particle size distribution of the resulting resin particle dispersion.

[0067] In the method for producing a resin particle dispersion according to the present embodiment, in the first and second production lines 100A and 100B, a resin particle dispersion is produced by a phase inversion emulsion production step and an organic solvent removal step, and in the next cycle, each step is carried out, and the resin particle dispersion can be repeatedly produced.

[0068] Here, in the method for producing a resin particle dispersion according to the present embodiment, in the first and second production lines 100A and 100B, at least one of the types of two or more organic solvents, the mixing ratio of two or more organic resins, and the type of resin is changed from each other, or the types of two or more organic resins, the mixing ratio of two or more organic resins, and the type of resin are made the same, and a resin particle dispersion can be produced.

[0069] Further, in the method for producing a resin particle dispersion according to the present embodiment, in each of the first and second production lines 100A and 100B, for each production cycle, at least one of the types of two or more organic solvents, the mixing ratio of two or more organic solvents, and the type of resin is changed, or the types of two or more organic solvents, the mixing ratio of two or more organic solvents, and the type of resin are made the same, and a resin particle dispersion can be produced.

[0070] In the method for producing a resin particle dispersion according to the present embodiment described above, the amount of residual liquid to be discarded can be reduced.

[0071] Here, in the method for producing a resin particle dispersion according to the present embodiment, a form in which two residual liquid recovery tanks are provided has been described, but as described above, three or more tanks may be provided. For example, the method for producing a resin particle dispersion according to the present embodiment may use a production apparatus provided with third residual liquid recovery tanks 32A and 32B as shown in FIG. 2.

[0072] The third residual liquid recovery tanks 32A and 32B are connected to the distillation tanks 20A and 20B by solvent discharge pipes 52A and 52B. The third retained liquid recovery tanks 32A and 32B are connected to the first retained liquid feed pipe 201A and the second retained liquid feed pipe 201B via the valves 34A and 34B by the third retained liquid feed pipes 33A and 33B. Thereby, the retained liquid recovered in the third retained liquid recovery tanks 32A and 32B is fed to one or both of the first reused retained liquid storage tank 200A and the second reused retained liquid storage tank 200B by operating the valves 34A and 34B. In addition, since the configuration other than the above is the same as that of the manufacturing apparatus shown in FIG. 2 and the manufacturing apparatus shown in FIG. 1, the description thereof will be omitted.

[0073] In the method for producing a resin particle dispersion liquid according to the present embodiment using the manufacturing apparatus shown in FIG. 2, by providing the third retained liquid recovery tanks 32A and 32B, even if the amount of the aqueous medium concentration of the retained liquid varies greatly depending on the organic solvent mixing ratio and the amount of the organic solvent, for example, the amount at which the aqueous medium concentration of the retained liquid becomes 95% or more, the third retained liquid recovery tank can be used as a buffer tank. Thereby, the amount of the retained liquid to be discarded can be further reduced.

[0074] Hereinafter, various materials used in the method for producing a resin particle dispersion liquid according to the present embodiment will be described.

[0075] - 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-based resins composed of copolymers obtained by combining two or more of these monomers. Examples of the resin 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 vinyl resins, or graft polymers obtained by polymerizing vinyl monomers in the presence of these. These resins may be used alone or in combination of two or more.

[0076] The resin is preferably a resin having polar groups such as carboxyl groups, sulfonic acid groups, hydroxy groups, etc., and particularly preferably a resin having an acid value.

[0077] It is preferable to apply an amorphous resin as the resin. However, a crystalline resin (for example, a crystalline polyester resin) may also be applied. Here, the amorphous resin means a resin having only a stepwise endothermic change but no distinct endothermic peak in a thermal analysis measurement using differential scanning calorimetry (DSC), being a solid at normal temperature, and being thermoplastified at a temperature equal to or higher than the glass transition temperature. On the other hand, the crystalline resin means a resin having a distinct endothermic peak rather than a stepwise change in the endothermic amount in differential scanning calorimetry (DSC). Specifically, for example, the 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 the amorphous resin means a resin having a half-width exceeding 10 °C or a resin in which no distinct endothermic peak is observed.

[0078] The amorphous resin will be described. Examples of the amorphous resin include known amorphous resins such as amorphous polyester resins, amorphous vinyl resins (for example, styrene acrylic resins, etc.), epoxy resins, polycarbonate resins, and polyurethane resins. Among these, amorphous polyester resins and amorphous vinyl resins (particularly styrene acrylic resins) are preferable, and amorphous polyester resins are more preferable. In addition, 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.

[0079] ·Amorphous polyester resin Examples of the amorphous polyester resin include condensation polymers of polyvalent carboxylic acids and polyhydric alcohols. As the amorphous polyester resin, commercially available products may be used, or those synthesized may be used.

[0080] Examples of the polyvalent carboxylic acids 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 acids. 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 acids 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.

[0081] 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.), and aromatic diols (e.g., ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). Among these, as the polyhydric alcohol, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable. As the polyhydric alcohol, a polyhydric alcohol having a crosslinked structure or a branched structure with a valence of 3 or more may be used in combination with the diol. Examples of the polyhydric alcohol having a valence of 3 or more include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohol may be used alone or in combination of two or more.

[0082] The amorphous polyester resin is obtained by a known production method. Specifically, for example, it is obtained by a method in which the polymerization temperature is set to 180 °C or higher and 230 °C or lower, the inside of the reaction system is depressurized as necessary, and the reaction is carried out while removing water and alcohol generated during condensation. When the raw material monomer 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 a monomer having poor compatibility exists in the copolymerization reaction, it is preferable to condense the monomer having poor compatibility with the acid or alcohol to be polycondensed in advance and then carry out the polycondensation with the main component.

[0083] 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, and more preferably 10 mgKOH / g or more and 16 mgKOH / g or less.

[0084] 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 was taken, 100 ml of a solvent (a mixed solution of diethyl ether / ethanol), and several drops of an indicator (phenolphthalein solution) were added, and the mixture was shaken well on a water bath until the sample was completely dissolved. This was titrated with a 0.1 mol / l potassium hydroxide ethanol solution, and the end point was determined when the faint red color of the indicator persisted for 30 seconds. When the acid value was A, the sample amount was S (g), the 0.1 mol / l potassium hydroxide ethanol solution used for titration was B (ml), and f was the factor of the 0.1 mol / l potassium hydroxide ethanol solution, A was calculated as A = (B × f × 5.611) / S.

[0085] 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 Co., Ltd.: DSC3110, thermal analysis system 001). The melting point of a mixture of indium and zinc was used for temperature correction of the detection part of this apparatus, and the heat of fusion of indium was used for heat correction. The sample was placed in an aluminum pan, the aluminum pan containing the sample and a control empty aluminum pan were set, and the measurement was carried out at a heating rate of 10°C / min. 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 the measurement is taken as the glass transition temperature.

[0086] The weight average molecular weight (Mw) of the resin is preferably 5000 or higher and 1000000 or lower, more preferably 7000 or higher and 500000 or lower. The number average molecular weight (Mn) of the resin is preferably 2000 or higher and 100000 or lower. The molecular weight distribution Mw / Mn of the resin is preferably 1.5 or higher and 100 or lower, more preferably 2 or higher and 60 or lower. 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 GPC·HLC-8120GPC manufactured by Tosoh as the measuring device, using a column·TSKgel SuperHM-M (15 cm) manufactured by Tosoh, 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.

[0087] 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.

[0088] -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 (for example, sodium hydroxide, lithium hydroxide, potassium hydroxide, etc.), carbonates (for example, sodium carbonate, sodium hydrogen carbonate, 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 that ammonia is added in the state of an aqueous ammonia solution.

[0089] 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.

[0090] 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 neutralizing agent (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. Degree of neutralization in resin [%]=mb×n×56.1÷Mwb÷AV×1000

[0091] -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 includes one or more organic solvents selected from the group consisting of esters and ketones, and one or more organic solvents selected from alcohols.

[0092] Examples of the esters include ethyl acetate, butyl acetate, propyl acetate, isopropyl acetate, etc. Examples of the ketones include acetone, methyl ethyl ketone, cyclohexanone, butanone, methyl isobutyl ketone, etc. Examples of the alcohols include methanol, ethanol, isopropyl alcohol, n-propanol, n-butanol, diacetone alcohol, 2-ethylhexanol, etc.

[0093] -Aqueous medium- As the aqueous medium, for example, water (such as distilled water, ion-exchanged water, etc.) is applicable. 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.

[0094] A surfactant may be added to the resin particle dispersion obtained by the method for producing a resin particle dispersion according to the present embodiment. 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.

[0095] Examples of the surfactant 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 preferable as the surfactant.

[0096] Examples of the anionic surfactant include carboxylic acid type, sulfate ester type, sulfonic acid type, and phosphate ester type anionic surfactants. Examples of the anionic surfactant 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 esters, sulfated oils, sulfated fatty acid alkyl esters, α-olefin sulfonates, secondary alkane sulfonates, α-sulfofatty 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.

[0097] 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.

[0098] 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.

[0099] (Properties of the 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 when 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.

[0100] 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 becomes 50% with respect to all particles is measured as the volume average particle diameter D50v.

[0101] 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 becomes easier to suppress the decrease in the yield caused by the adhesion of the resin to the inner wall surface of the distillation 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, 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 can be mentioned.

[0102] The solid content concentration of the resin particle dispersion according to this embodiment may be appropriately selected as needed, but is preferably 1 mass% or more and 60 mass% or less, more preferably 5 mass% or more and 50 mass% or less, and particularly preferably 10 mass% or more and 50 mass% or less.

[0103] (Use) The method for producing the resin particle dispersion according to this embodiment is typically applied to the method for producing a resin particle dispersion for toner. Other uses include those for inkjet ink, cosmetics, powder coatings, various coating paints, electronic paper ink, and the like.

[0104] <Method for producing toner / Toner> The method for producing 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 forming step), and The aggregated particle dispersion in which the aggregated particles are dispersed is heated so that the aggregated particles are fused and united to form toner particles (hereinafter, the aggregation and unification step), and has.

[0105] The toner according to this embodiment is a toner having toner particles obtained by the method for producing toner according to the above embodiment.

[0106] 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, but 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.

[0107] -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 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.

[0108] · Coloring agent particle dispersion liquid The coloring agent particle dispersion liquid is a dispersion liquid in which at least a coloring agent is dispersed in an aqueous medium. Examples of the coloring agent 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, etc. The coloring agent may be used alone or in combination of two or more.

[0109] The coloring 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, an attritor, or a high-pressure counter-collision type disperser is preferably used. Further, the coloring agent may be dispersed in the aqueous medium using a polar ionic surfactant and a homogenizer to prepare a coloring agent particle dispersion liquid.

[0110] The volume average particle diameter of the coloring agent 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 dispersants added to stabilize the dispersion stability of colorants in an aqueous medium and lower the energy of the colorants in the toner include rosin, rosin derivatives, coupling agents, polymer dispersants, and the like.

[0111] · Release agent particle dispersion The release agent particle dispersion is a dispersion in which at least a release agent is dispersed in an aqueous medium. Examples of release agents 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 from the DSC curve obtained by differential scanning calorimetry (DSC) according to the "melting peak temperature" described in the method for determining the melting temperature in JIS K 7121-1987 "Method for Measuring Transition Temperature of Plastics".

[0112] 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. Also, 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. 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.

[0113] - Agglomerated particle formation step - Next, the colorant particle dispersion and the release agent particle dispersion are mixed together with the resin particle dispersion. Then, in the mixed dispersion liquid, the resin particles, the colorant particles, and the release agent particles are hetero-aggregated to form aggregated 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.

[0114] Specifically, for example, a flocculant is added to the mixed dispersion liquid, the pH of the mixed dispersion liquid is adjusted to be acidic (for example, the pH is 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. Then, after heating to the temperature of the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles - 30°C or more and the glass transition temperature of the resin particles - 10°C or less), 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 be 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.

[0115] Examples of the flocculant include surfactants having a reverse polarity to the surfactant used as a dispersant added to the mixed dispersion liquid, inorganic metal salts, and metal complexes having a valence of 2 or more. In particular, when a metal complex is used as the flocculant, the amount of the surfactant used is reduced and the charging characteristics are improved. An additive that forms a complex or a similar bond with the metal ion of the flocculant may be used as necessary. As this additive, a chelating agent is preferably used.

[0116] 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). As the addition amount of the chelating agent, for example, 0.01 part by mass or more and 5.0 parts by mass or less, preferably 0.1 part by mass or more and less than 3.0 parts by mass, per 100 parts by mass of the resin particles is preferable.

[0117] -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), to fuse and unify the aggregated particles and form toner particles.

[0118] Through the above steps, toner particles are obtained. 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. And heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and unify the second aggregated particles to form toner particles having a core / shell structure, and then manufacturing toner particles.

[0119] 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. In addition, the solid-liquid separation step is not particularly limited, but 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.

[0120] And the toner and its manufacturing method according to the present embodiment are manufactured, for example, by adding and mixing an external additive to the obtained toner particles in a dried state. The mixing is preferably performed by, for example, 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.

[0121] 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.

[0122] 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 hydrophobization treatment agent. The hydrophobization treatment 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 hydrophobization treatment 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.

[0123] 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.

[0124] 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, with respect to the toner particles.

[0125] -Properties of the toner- In the toner according to this 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 are preferably composed of a core part containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing a binder resin.

[0126] 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.

[0127] In addition, various average particle diameters and various particle size distribution indexes 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 by 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.

[0128] 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.

[0129] 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 for obtaining the average circularity is set to 3500. 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.

[0130] <Electrostatic charge image developer> The electrostatic charge image developer according to this embodiment contains at least the toner according to this embodiment. The electrostatic charge image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or a two-component developer in which the toner and a carrier are mixed.

[0131] 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. Note that 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

[0132] 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.

[0133] <Synthesis of polyester resin (1)> In a reaction vessel equipped with a stirrer, a thermometer, 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, dibutyltin oxide was added as a catalyst, nitrogen gas was introduced into the vessel to maintain an inert atmosphere, and after heating up, a co-condensation polymerization reaction was carried out at 230 °C for about 12 hours. 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 mg KOH / g, the glass transition temperature (Tg) was 58 °C, and the melting point (Tm) was 109 °C.

[0134] <Synthesis of polyester resin (2)> In a reaction vessel equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet tube, 3 mol parts of a bisphenol A ethylene oxide 2 mol adduct, 57 mol parts of a bisphenol A propylene oxide 2 mol adduct, 15 mol parts of terephthalic acid, and 35 mol parts of fumaric acid were used as raw materials, dibutyltin oxide was added as a catalyst, nitrogen gas was introduced into the vessel to maintain an inert atmosphere, and after heating up, a co-condensation polymerization reaction was carried out at 250 °C for about 8 hours. Then, the pressure was gradually reduced at 220 °C to synthesize a polyester resin (2). The weight average molecular weight (Mw) of the obtained polyester resin (2) was 23,000, the acid value was 15.0 mg KOH / g, the glass transition temperature (Tg) was 62 °C, and the melting point (Tm) was 106 °C.

[0135] <Example 1> -Production of resin particle dispersion liquid in the first production cycle- Using the production apparatus shown in Figure 1, the resin particle dispersion liquid for the first production cycle was produced as follows.

[0136] In the first production line 100A, the resin particle dispersion liquid was produced as follows. Into an emulsification tank 10A equipped with a stirrer 11A and a thermometer, 90 parts of ethyl acetate and 25 parts of isopropanol as organic solvents and 100 parts of polyester resin (1) as a resin were added, and the mixture was stirred at 70 °C for 30 minutes to dissolve the resin. After adding 4 parts of 10% by mass aqueous ammonia as a neutralizing agent to the obtained dissolved solution, 300 parts of pure water at 65 °C was gradually added to obtain an inverse phase emulsion. Then, the obtained inverse phase emulsion was fed into a distillation tank 20A equipped with a stirrer 21A and a thermometer. In the distillation tank 20A, the pressure was reduced to 8 kPa and heated to 65 °C to carry out vacuum distillation of the inverse phase emulsion. The evaporated water vapor containing the organic solvent was cooled by a condenser 54A, the composition of the distillate was detected by an analysis unit 55A, the distillate with a water medium concentration of 95% or less was recovered in a first distillate recovery tank 30A, and the distillate with a water medium concentration exceeding 95% was recovered in a second distillate recovery tank 21A.

[0137] In parallel with the first production line 100A, a resin particle dispersion was produced in a second production line 100B as follows. Into an emulsification tank 10B equipped with a stirrer 11B and a thermometer, 45 parts of ethyl acetate and 18 parts of isopropanol as organic solvents and 100 parts of polyester resin (2) as a resin were added, and the mixture was stirred at 70 °C for 30 minutes to dissolve the resin. After adding 5 parts of 10% by mass aqueous ammonia as a neutralizing agent to the obtained dissolved solution, 350 parts of pure water at 65 °C was gradually added to obtain an inverse phase emulsion. Then, the obtained inverse phase emulsion was fed into a distillation tank 20B equipped with a stirrer 21B and a thermometer. In the distillation tank 20B, the pressure was reduced to 8 kPa and heated to 65 °C to carry out vacuum distillation of the inverse phase emulsion. The evaporated water vapor containing the organic solvent was cooled by a condenser 54B, the composition of the distillate was detected by an analysis unit 55B, the distillate with a water medium concentration of 95% or less was recovered in a first distillate recovery tank 30B, and the distillate with a water medium concentration exceeding 95% was recovered in a second distillate recovery tank 31B.

[0138] The retained liquid recovered in the first retained liquid recovery tanks 30A and 30B of the first and second production lines 100A and 100B was sent to the first reuse retained liquid storage tank 200A, stirred and homogenized, and then the composition analysis of the retained liquid stored in the first reuse retained liquid storage tank 200A was performed. As a result, the composition of the retained liquid was 43.3% by mass of ethyl acetate, 13.6% by mass of isopropanol, 0.3% by mass of ammonia, and 42.8% by mass of water, and the total amount of the retained liquid was 306 parts. The retained liquid recovered in the second retained liquid recovery tanks 31A and 31B of the first and second production lines 100A and 100B was sent to the second reuse retained liquid storage tank 200B, stirred and homogenized, and then the composition analysis of the retained liquid stored in the second reuse retained liquid storage tank 200B was performed. As a result, the composition of the retained liquid was 2.3% by mass of ethyl acetate, 1.1% by mass of isopropanol, 0.2% by mass of ammonia, and 96.4% by mass of water, and the total amount of the retained liquid was 119 parts.

[0139] -Manufacture of the resin particle dispersion liquid in the second production cycle- Using the manufacturing apparatus shown in Fig. 1, for both the first and second production lines 100A and 100B, a resin particle dispersion liquid for the second production cycle was manufactured in the same manner as in the first production cycle, except that polyester resin (1) was used as the resin and the organic solvent mixing ratio was set to "90 parts of ethyl acetate / 25 parts of isopropanol". However, based on the organic solvent mixing ratio (90 parts of ethyl acetate / 25 parts of isopropanol) and the organic solvent mixing ratio (43.3% by mass / 13.6% by mass) in the retained liquid stored in the first reuse retained liquid storage tank 200A in the first production cycle, the amount of the reused retained liquid to be used as the organic solvent was determined to be 183 parts. And the amount of the new organic solvent to be used was determined to be 10.7 parts of ethyl acetate. Then, 183 parts of the retained liquid stored in the first reuse retained liquid storage tank 200A in the first production cycle and 10.7 parts of new ethyl acetate as the organic solvent, and 100 parts of polyester resin (1) as the resin were added to the emulsification tanks 10A and 10B, stirred at 70 °C for 30 minutes to dissolve the resin. After adding 3.5 parts of 10% by mass aqueous ammonia as the neutralizing agent to the obtained dissolved solution, 262 parts of pure water at 65 °C was gradually added to phase-invert and emulsify the resin. After that, 38 parts of the liquid stored in the second reuse liquid storage tank 200B in the first production cycle was fed as makeup water to the emulsification tanks 10A and 10B.

[0140] The new organic solvent usage rate in the second production cycle was calculated as (new ethyl acetate amount + new isopropanol amount) / (new ethyl acetate amount + ethyl acetate amount in the retained liquid + new isopropanol amount + isopropanol amount in the retained liquid) × 100. As a result, the new organic solvent usage rate in the second production cycle was 9.3%.

[0141] <Example 2> - Production of resin particle dispersion in the first production cycle - In the same manner as in Example 1, a resin particle dispersion of polyester resin (1) was produced on the first production line 100A, and a resin particle dispersion of polyester resin (2) was produced on the second production line 100B.

[0142] - Production of resin particle dispersion in the second production cycle - Using the production apparatus shown in Fig. 1, a resin particle dispersion for the second production cycle was produced in the same manner as in the first production cycle, except that polyester resin (2) was used as the resin for both the first and second production lines 100A and 100B, and the organic solvent mixing ratio was set to "45 parts of ethyl acetate / 18 parts of isopropanol". However, based on the organic solvent mixing ratio (45 parts of ethyl acetate / 18 parts of isopropanol) and the organic solvent mixing ratio (43.3 mass% / 13.6 mass%) in the retained liquid stored in the first reuse liquid storage tank 200A in the first production cycle, the amount of the reused retained liquid to be used as the organic solvent was determined to be 104 parts. And the amount of the new organic solvent used was determined to be 3.8 parts by mass of isopropanol. Then, 104 parts of the retained liquid stored in the first reuse liquid storage tank 200A in the first production cycle and 3.8 parts of new isopropanol as the organic solvent, and 100 parts of polyester resin (2) as the resin were added to the emulsification tanks 10A and 10B, and stirred at 70°C for 30 minutes to dissolve the resin. After adding 4.7 parts of 10 mass% aqueous ammonia as a neutralizing agent to the obtained dissolved solution, 269 parts of pure water at 65°C was gradually added to phase-invert and emulsify the resin. Subsequently, 81 parts of the liquid retained in the second reuse liquid storage tank 200B during the first manufacturing cycle was fed as makeup water to the emulsification tanks 10A and 10B.

[0143] The new organic solvent usage rate in the second manufacturing cycle was calculated as (new ethyl acetate amount + new isopropanol amount) / (new ethyl acetate amount + ethyl acetate amount in the retained liquid + new isopropanol amount + isopropanol amount in the retained liquid) × 100. As a result, the new organic solvent usage rate in the second manufacturing cycle was 6.1%.

[0144] <Example 3> -Manufacture of the resin particle dispersion in the first manufacturing cycle- Using the manufacturing apparatus shown in Fig. 2, the resin particle dispersion for the first manufacturing cycle was manufactured as follows.

[0145] In the first production line 100A, a resin particle dispersion was produced as follows. To the emulsification tank 10A equipped with a stirrer 11A and a thermometer, 150 parts of ethyl acetate and 40 parts of isopropanol as organic solvents, and 100 parts of polyester resin (1) as a resin were added, and the mixture was stirred at 70 °C for 30 minutes to dissolve the resin. After adding 4 parts of 10 mass% aqueous ammonia as a neutralizing agent to the obtained dissolved solution, 300 parts of pure water at 65 °C was gradually added to obtain a phase-inverted emulsion. Subsequently, the obtained phase-inverted emulsion was fed to the distillation tank 20A equipped with a stirrer 21A and a thermometer. In the distillation tank 20A, the pressure was reduced to 8 kPa and heated to 65 °C to perform vacuum distillation on the phase-inverted emulsion. The evaporated organic solvent-containing water vapor was cooled by the condenser 54A, and the recovery was started in the first retained liquid recovery tank 30A. Before the water medium concentration reached 95% or less, the first retained liquid recovery tank 30A became full, and the recovery destination was switched to the third retained liquid recovery tank 32A. Subsequently, when the water medium concentration reached 95% or less by the analysis unit 55B of the retained liquid, the recovery was switched to the second retained liquid recovery tank 31A to recover the retained liquid.

[0146] In parallel with the first production line 100A, in the second production line 100B, a resin particle dispersion was produced as follows. In an emulsification tank 10B equipped with a stirrer 11B and a thermometer, 40 parts of ethyl acetate and 15 parts of isopropanol as organic solvents and 100 parts of polyester resin (1) as a resin were added, and the mixture was stirred at 70 °C for 30 minutes to dissolve the resin. After adding 5 parts of 10% by mass aqueous ammonia as a neutralizing agent to the obtained dissolved solution, 600 parts of pure water at 65 °C was gradually added to obtain a phase-inverted emulsion. Then, the obtained phase-inverted emulsion was fed into a distillation tank 20B equipped with a stirrer 21A and a thermometer. In the distillation tank 20B, the pressure was reduced to 8 kPa and heated to 65 °C to carry out vacuum distillation of the phase-inverted emulsion. The evaporated water vapor containing the organic solvent was cooled by a condenser 54B, and the recovery was started in a first distillate recovery tank 30B. The composition of the distillate was detected by an analysis unit 55B, and when the water medium concentration became 95% or less, the recovery destination was switched to a second distillate recovery tank 31B. Before the end of distillation, the second distillate recovery tank 31B became full, and the recovery destination was switched to a third distillate recovery tank 32B for recovery.

[0147] The distillates recovered in the first distillate recovery tank 30A and the third distillate recovery tank 32A of the first production line 100A and the first distillate recovery tank 30B of the second production line 100B were fed into a first reused distillate storage tank 200A, stirred and homogenized, and then the composition of the distillate stored in the first reused distillate storage tank 200A was analyzed. As a result, the composition of the distillate was 44.4% by mass of ethyl acetate, 12.7% by mass of isopropanol, 0.2% by mass of ammonia, and 42.7% by mass of water, and the total amount of the distillate was 419 parts.

[0148] The distillates recovered in the second distillate recovery tank 31A of the first production line 100A and the second distillate recovery tank 31B and the third distillate recovery tank 32B of the second production line 100B were fed into a second reused distillate storage tank 200B, stirred and homogenized, and then the composition of the distillate stored in the second reused distillate storage tank 200B was analyzed. As a result, the composition of the distillate was 1.2% by mass of ethyl acetate, 0.5% by mass of isopropanol, 0.1% by mass of ammonia, and 98.2% by mass of water, and the total amount of the distillate was 317 parts.

[0149] -Manufacture of resin particle dispersion in the second production cycle- Using the manufacturing apparatus shown in FIG. 2, for both the first and second manufacturing lines 100A and 100B, a resin particle dispersion liquid for the second manufacturing cycle was produced in the same manner as the first manufacturing cycle, except that polyester resin (1) was used as the resin and the organic solvent mixing ratio was set to "40 parts of ethyl acetate / 15 parts of isopropanol". However, based on the organic solvent mixing ratio (40 parts of ethyl acetate / 15 parts of isopropanol) and the organic solvent mixing ratio (44.4 mass% / 12.7 mass%) in the retained liquid stored in the first reused liquid storage tank 200A in the first manufacturing cycle, the amount of the reused liquid to be used as the organic solvent was determined to be 90 parts. And the usage amount of the new organic solvent was determined to be 3.5 parts by mass of isopropanol. Then, 90 parts of the retained liquid stored in the first reused liquid storage tank 200A in the first manufacturing cycle as the organic solvent, 3.5 parts of new isopropanol, and 100 parts of polyester resin (1) as the resin were added to the emulsification tanks 10A and 10B, and stirred at 70 ° C for 30 minutes to dissolve the resin. After adding 4.8 parts of 10 mass% aqueous ammonia as a neutralizing agent to the obtained dissolved solution, 316 parts of pure water at 65 ° C was gradually added to phase-invert and emulsify the resin. Thereafter, 284 parts of the retained liquid stored in the second reused liquid storage tank 200B in the first manufacturing cycle was fed as makeup water to the emulsification tanks 10A and 10B.

[0150] The new organic solvent usage rate in the second manufacturing cycle was calculated as (new amount of ethyl acetate + new amount of isopropanol) / (new amount of ethyl acetate + amount of ethyl acetate in the retained liquid + new amount of isopropanol + amount of isopropanol in the retained liquid) × 100. As a result, the new organic solvent usage rate in the second manufacturing cycle was 6.4%.

[0151] <Comparative Example 1> A manufacturing apparatus shown in FIG. 3 having the same configuration as the manufacturing apparatus shown in FIG. 1 was prepared, except that only the first manufacturing line 100A was provided and the retained liquids recovered in the first retained liquid recovery tank 30A and the second retained liquid recovery tank 31A were directly fed to the emulsification tank 10A, respectively. In addition, in Fig. 3, 211A indicates the first retained liquid supply pipe connecting the first retained liquid recovery tank 30A and the emulsification tank 10A, 211B indicates the second retained liquid supply pipe connecting the second retained liquid recovery tank 31A and the emulsification tank 10A, 210A and 210B indicate pumps, and 212A and 212B indicate valves.

[0152] Then, except for using the manufacturing apparatus shown in Fig. 3, a resin particle dispersion liquid of the first manufacturing cycle was produced under the same conditions as the second manufacturing line 100B of Example 1, and the production of the resin particle dispersion liquid of the second manufacturing cycle was carried out under the same conditions as the first manufacturing line 100A of Example 1. However, in the production of the resin particle dispersion liquid of the second manufacturing cycle, the reuse amount of the retained liquid recovered in the first retained liquid recovery tank 30A, which is reused as an organic solvent, was set to 153 parts based on the organic solvent mixture (ethyl acetate 41.2 mass% / isopropanol 16.3 mass%) in the retained liquid of the first retained liquid recovery tank 30B. And the usage amount of the new organic solvent was determined to be 26.9 parts of ethyl acetate. The new organic solvent usage rate in the second manufacturing cycle was calculated as (new ethyl acetate amount + new isopropanol amount) / (new ethyl acetate amount + ethyl acetate amount in the retained liquid + new isopropanol amount + isopropanol amount in the retained liquid) × 100. As a result, the new organic solvent usage rate in the second manufacturing cycle was 23.4%.

[0153] From the above results, it can be seen that in the method for producing the resin particle dispersion liquid of the present example, the amount of the retained liquid to be discarded can be reduced as compared with the comparative example.

Explanation of symbols

[0154] 10A, 10B Emulsification tank 11A, 11B Stirrer 20A, 20B Distillation tank 21A, 21B Stirrer 30A, 30B First retained liquid recovery tank 31A, 31B Second retained liquid recovery tank 32A, 32B Third retained liquid recovery tank 40A, 40B Resin storage tank 41A, 41B Resin supply pipe 42A and 42B Neutralizer Storage Tanks 43A and 43B Neutralizer Supply Tubes 44A and 44B Organic Solvent Storage Tanks 45A and 45B Organic Solvent Supply Tubes 46A and 46B Aqueous Medium Storage Tanks 47A and 47B Aqueous Medium Supply Tubes 50A and 50B Emulsion Feed Tubes 52A and 52B Solvent Drain Tubes 54A and 54B Condensers 55A and 55B Analysis Sections 100A First Production Line 100B Second Production Line 200A First Reuse Retention Liquid Storage Tank 200B Second Reuse Retention Liquid Storage Tank 201A First Retention Liquid Feed Tube 201B Second Retention Liquid Feed Tube 203A First Storage Retention Liquid Feed Tube 203B Second Storage Retention Liquid Feed Tube

Claims

1. An emulsification tank that uses two or more organic solvents and an aqueous medium to phase-invert emulsify a resin to obtain a phase-inverted emulsion, a distillation tank that removes the organic solvent from the phase-inverted emulsion by vacuum distillation to obtain a resin particle dispersion, and a plurality of distillate recovery tanks that recover the distillate generated by the vacuum distillation for each target distillate composition, and a manufacturing line for two or more resin particle dispersions having the same; In the manufacturing line of each of the two or more resin particle dispersions, among the distillates recovered by the plurality of distillate recovery tanks, a reuse distillate storage tank A that collects and stores the distillates recovered by at least one distillate recovery tank A; Using a manufacturing apparatus for a resin particle dispersion provided with the same; A method for manufacturing a resin particle dispersion, wherein the distillate is sent from the reuse distillate storage tank A to the emulsification tank of at least one of the manufacturing lines of the two or more resin particle dispersions and reused for the production of the phase-inverted emulsion.

2. The amount of the reuse distillate is determined from the mixing ratio of two or more organic solvents in the distillate stored in the reuse distillate storage tank A and the mixing ratio of two or more organic solvents during the production of the phase-inverted emulsion, and the distillate in the determined amount of the reuse distillate is sent from the reuse distillate storage tank A to the emulsification tank of at least one of the manufacturing lines of the two or more resin particle dispersions and reused for the production of the phase-inverted emulsion. The method for manufacturing a resin particle dispersion according to Claim 1.

3. The composition of the distillate is analyzed by at least one measurement selected from the group consisting of weight measurement, gas chromatography measurement, liquid chromatography measurement, infrared spectroscopy measurement, ultrasonic propagation velocity measurement, neutralization titration, specific gravity measurement, and conductivity measurement of the distillate, and for each target distillate composition, the distillate recovery tank for recovering the distillate is changed. The method for manufacturing a resin particle dispersion according to Claim 1 or Claim 2.

4. Calculate the mixing ratio of two or more organic solvents in the retained liquid stored in the reuse retained liquid storage tank A based on the mixing ratio and amount of two or more organic solvents during the production of the phase inversion emulsion, the amount of the retained liquid recovered in the retained liquid recovery tank A, and the amount of the retained liquid stored in the reuse retained liquid storage tank A. The method for producing a resin particle dispersion according to any one of claims 1 to 3.

5. Measure the mixing ratio of two or more organic solvents in the retained liquid stored in the reuse retained liquid storage tank A by at least one measurement selected from the group consisting of gas chromatography measurement, liquid chromatography measurement, infrared spectroscopy measurement, ultrasonic propagation velocity measurement, neutralization titration, specific gravity measurement, and conductivity measurement. The method for producing a resin particle dispersion according to any one of claims 1 to 3.

6. Store a retained liquid with an organic solvent content of 30% by mass or more in the reuse retained liquid storage tank A. The method for producing a resin particle dispersion according to any one of claims 1 to 5.

7. Feed the retained liquid with an organic solvent content of 30% by mass or more stored in the reuse retained liquid storage tank A to the emulsification tank as an organic solvent. The method for producing a resin particle dispersion according to claim 6.

8. The resin particle dispersion production apparatus includes, in each of the two or more resin particle dispersion production lines, a reuse retained liquid storage tank B that collects and stores the retained liquid recovered in at least one of the plurality of retained liquid recovery tanks among the retained liquid recovered in the plurality of retained liquid recovery tanks. Store a retained liquid with an aqueous medium content of 80% by mass or more in the reuse retained liquid storage tank B. Feed the retained liquid with an aqueous medium content of 80% by mass or more from the reuse retained liquid storage tank B to the emulsification tank of at least one of the two or more resin particle dispersion production lines for reuse in the production of the phase inversion emulsion. The method for producing a resin particle dispersion according to any one of claims 6 or 7.

9. The method for producing a resin particle dispersion according to claim 8, wherein the retained liquid containing 80% by mass or more of the aqueous medium stored in the reuse retained liquid storage tank B is subjected to phase inversion emulsification of the resin using two or more organic solvents and an aqueous medium, and then fed to the emulsification tank.

10. In the production lines of the two or more resin particle dispersions, at least one of the types of the two or more organic resins, the mixing ratio of the two or more organic resins, and the type of the resin is changed mutually, or the types of the two or more organic resins, the mixing ratio of the two or more organic resins, and the type of the resin are made the same to produce a resin particle dispersion. The method for producing a resin particle dispersion according to any one of claims 1 to 9.

11. In the production lines of each of the two or more resin particle dispersions, for each production cycle, at least one of the types of the two or more organic resins, the mixing ratio of the two or more organic resins, and the type of the resin is changed mutually, or the types of the two or more organic resins, the mixing ratio of the two or more organic resins, and the type of the resin are made the same to produce a resin particle dispersion. The method for producing a resin particle dispersion according to any one of claims 1 to 10.

12. 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 11, A step of aggregating at least the resin particles in the 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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