# US 6,723,785 B2 · Process for preparing aqueous dispersion of pigment-containing polymer particles

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- Number: US 6,723,785 B2
- Document ID: US6723785B2
- Status: Granted
- Kind: B2
- Application number: 09/904,887
- Filed: 2001-07-16
- Published: 2002-02-28
- Granted: 2004-04-20
- Earliest claimed: 2000-07-17
- Assignees: Kao Corporation
- Inventors: Yoshinori Hama; Kenji Kano; Norio Ueyama; Masahiro Umehara
- Web page: https://patentgrep.com/patent/US6723785B2

## CPC

- C08J 3/212: {and solid additives}
- 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)

## Abstract

A process for preparing an aqueous dispersion of pigment-containing polymer particles, comprising the steps of (A) removing an organic solvent from a mixture (I) comprising an organic solvent solution of a polymer, water and optionally a neutralizing agent to give a solvent-removed product; and (B) subjecting the solvent-removed product obtained in step (A) to a dispersion treatment, wherein a pigment is added to the mixture (I) or the solvent-removed product. The aqueous dispersion of pigment-containing polymer particles can be suitably used for a water-based ink for inkjet printing.

## Claims

### Claim 1

A process for preparing an aqueous dispersion of pigment-containing polymer particles, comprising the steps of:
(A) removing an organic solvent from a mixture (I) comprising an organic solvent solution of a polymer, water and optionally a neutralizing agent by distillation under reduced pressure to give a solvent-removed product; and
(B) subjecting the solvent-removed product obtained in step (A) to a dispersion treatment,
wherein a pigment is added to the mixture (I) or the solvent-removed product.

### Claim 2 (depends on 1)

The process according to claim 1, wherein said organic solvent is at least one solvent selected from the group consisting of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, diacetone alcohol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, dibutyl ether, tetrahydrofuran, dioxane, benzene, toluene, heptane, hexane, cyclohexane, methylene chloride, 1,1,1-trichloroethane, chloroform, carbon tetrachloride, and 1,2-dichloroethane.

### Claim 3

A process for preparing an aqueous dispersion of pigment-containing polymer particles, comprising the steps of:
(C) mixing an organic solvent solution of a polymer, water and optionally a neutralizing agent with each other to give a mixture (II);
(D) removing the organic solvent from the mixture (II) obtained in step (C);
(E) mixing a solvent-removed product obtained in step (D) with a pigment to give a mixture (III); and
(F) subjecting the mixture (III) obtained in step (E) to a dispersion treatment.

### Claim 4 (depends on 3)

An aqueous dispersion of pigment-containing polymer particles obtained by the process of claim 3.

### Claim 5 (depends on 4)

A water-based ink composition comprising the aqueous dispersion of pigment-containing polymer particles of claim 4.

### Claim 6 (depends on 3)

The process according to claim 3, wherein said organic solvent is at least one solvent selected from the group consisting of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, diacetone alcohol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, dibutyl ether, tetrahydrofuran, dioxane, benzene, toluene, heptane, hexane, cyclohexane, methylene chloride, 1,1,1-trichloroethane, chloroform, carbon tetrachloride, and 1,2-dichloroethane.

### Claim 7

A process for preparing an aqueous dispersion of pigment-containing polymer particles, comprising the steps of:
(G) mixing an organic solvent solution of a polymer, water, pigment and optionally a neutralizing agent with each other to give a mixture (IV);
(H) removing the organic solvent from the mixture (IV) obtained in step (G) by distillation under reduced pressure to give a solvent-removed product; and
(I) subjecting the solvent-removed product obtained in step (H) to a dispersion treatment.

### Claim 8 (depends on 7)

The process according to claim 7, wherein said organic solvent is at least one solvent selected from the group consisting of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, diacetone alcohol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, dibutyl ether, tetrahydrofuran, dioxane, benzene, toluene, heptane, hexane, cyclohexane, methylene chloride, 1,1,1-trichloroethane, chloroform, carbon tetrachloride, and 1,2-dichloroethane.

### Claim 9

A process for preparing an aqueous dispersion of pigment-containing polymer particles, comprising the steps of:
(C) mixing an organic solvent solution of a polymer, water and optionally a neutralizing agent with each other to give a mixture (II);
(K) mixing the mixture (II) obtained in step (C) with a pigment to give a mixture (VI);
(L) removing the organic solvent from the mixture (VI) obtained in step (K) to give a solvent-removed product; and
(M) subjecting the solvent-removed product obtained in step (L) to a dispersion treatment.

### Claim 10 (depends on 9)

An aqueous dispersion of pigment containing polymer particles obtained by the process of claim 9.

### Claim 11 (depends on 10)

A water-based ink composition comprising the aqueous dispersion of pigment-containing polymer particles of claim 10.

### Claim 12 (depends on 9)

The process according to claim 9, wherein said organic solvent is at least one solvent selected from the group consisting of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, diacetone alcohol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, dibutyl ether, tetrahydrofuran, dioxane, benzene, toluene, heptane, hexane, cyclohexane, methylene chloride, 1,1,1-trichloroethane, chloroform, carbon tetrachloride, and 1,2-dichloroethane.

### Claim 13

A process for preparing an aqueous dispersion of pigment-containing polymer particles, comprising the steps of:
(N) mixing an organic solvent solution of a polymer with a pigment to give a mixture (VII);
(O) mixing the mixture (VII) obtained in step (N), water and optionally a neutralizing agent with each other to give a mixture (VIII);
(P) removing the organic solvent from the mixture (VIII) obtained in step (O) by distillation under reduced pressure to give a solvent-removed product; and
(Q) subjecting the solvent-removed product obtained in step (P) to a dispersion treatment.

### Claim 14 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)

An aqueous dispersion of pigment-containing polymer particles obtained by the process of any one of claims 1 to 13.

### Claim 15 (depends on 14)

A water-based ink composition comprising the aqueous dispersion of pigment-containing polymer particles of claim 14.

### Claim 16 (depends on 13)

The process according to claim 13, wherein said organic solvent is at least one solvent selected from the group consisting of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, diacetone alcohol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, dibutyl ether, tetrahydrofuran, dioxane, benzene, toluene, heptane, hexane, cyclohexane, methylene chloride, 1,1,1-trichloroethane, chloroform, carbon tetrachloride, and 1,2-dichloroethane.