# US 12,215,201 B2 · Method for producing resin particle dispersion, method for producing toner for electrostatic image development, and toner for electrostatic image development

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- Number: US 12,215,201 B2
- Document ID: US12215201B2
- Status: Granted
- Kind: B2
- Application number: 17/462,467
- Filed: 2021-08-31
- Published: 2022-09-29
- Granted: 2025-02-04
- Earliest claimed: 2021-03-26
- Assignees: FUJIFILM Business Innovation Corp.
- Applicants: FUJIFILM Business Innovation Corp.
- Inventors: Takashi Inukai; Keita Yamamoto
- Web page: https://patentgrep.com/patent/US12215201B2

## CPC

- C08J 3/05: from solid polymers
- G03G 9/0806: {whereby chemical synthesis of at least one of the toner components takes place}
- G03G 9/08755: {Polyesters}
- C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A method for producing a resin particle dispersion includes: preparing a phase-inverted emulsion by phase inversion emulsification of a resin using an organic solvent and an aqueous medium; and removing the organic solvent from the phase-inverted emulsion contained in a distillation tank by reduced pressure distillation. During the reduced pressure distillation, the rate of pressure reduction in an environment in which the pressure inside the distillation tank is equal to or higher than vapor pressure and equal to or lower than (the vapor pressure+5 kPa) when the concentration of the organic solvent in the phase-inverted emulsion is in the range of 30% by mass or less to 1% by mass or more is from 0.01 kPa/min to 0.5 kPa/min inclusive until the pressure inside the distillation tank reaches a preset reduced pressure for the reduced pressure distillation.

## Claims

### Claim 1

A method for producing a polyester resin particle dispersion, the method comprising:
preparing a phase-inverted emulsion by phase inversion emulsification of a polyester resin using an organic solvent and an aqueous medium; and
removing the organic solvent from the phase-inverted emulsion contained in a distillation tank by reduced pressure distillation,
wherein, during the reduced pressure distillation, the rate of pressure reduction in an environment in which the pressure inside the distillation tank is equal to or higher than vapor pressure and equal to or lower than (the vapor pressure+5 kPa) when the concentration of the organic solvent in the phase-inverted emulsion is in the range of 30% by mass or less to 1% by mass or more is from 0.01 kPa/min to 0.5 kPa/min inclusive until the pressure inside the distillation tank reaches a preset reduced pressure for the reduced pressure distillation.

### Claim 2 (depends on 1)

The method for producing a polyester resin particle dispersion according to claim 1, wherein the temperature of the phase-inverted emulsion during the reduced pressure distillation is from 30° C. to 70° C. inclusive.

### Claim 3 (depends on 1)

The method for producing a polyester resin particle dispersion according to claim 1, wherein heating temperature at which a tank wall of the distillation tank is heated during the reduced pressure distillation is from 50° C. to 95° C. inclusive.

### Claim 4 (depends on 2)

The method for producing a polyester resin particle dispersion according to claim 2, wherein heating temperature at which a tank wall of the distillation tank is heated during the reduced pressure distillation is from 50° C. to 95° C. inclusive.

### Claim 5 (depends on 1)

The method for producing a polyester resin particle dispersion according to claim 1, wherein a polyester resin particle dispersion for a toner is produced.

### Claim 6 (depends on 2)

The method for producing a polyester resin particle dispersion according to claim 2, wherein a polyester resin particle dispersion for a toner is produced.

### Claim 7 (depends on 3)

The method for producing a polyester resin particle dispersion according to claim 3, wherein a polyester resin particle dispersion for a toner is produced.

### Claim 8 (depends on 4)

The method for producing a polyester resin particle dispersion according to claim 4, wherein a polyester resin particle dispersion for a toner is produced.

### Claim 9 (depends on 1)

A method for producing a toner for electrostatic image development, the method comprising:
forming aggregated particles by aggregating, in a dispersion containing polyester resin particles in a polyester resin particle dispersion obtained by the polyester resin particle dispersion production method according to claim 1, at least the polyester resin particles;
and fusing and coalescing the aggregated particles by heating an aggregated particle dispersion containing the aggregated particles dispersed therein to thereby form toner particles.

### Claim 10 (depends on 1)

The method for producing a polyester resin particle dispersion according to claim 1, wherein the temperature of the phase-inverted emulsion during the reduced pressure distillation is from 42° C. to 70° C. inclusive.

### Claim 11 (depends on 1)

The method for producing a polyester resin particle dispersion according to claim 1, wherein the temperature of the phase-inverted emulsion during the reduced pressure distillation reaches from 50° C. to 70° C. inclusive.