Pigment dispersion and producing method thereof

Patent metadata

Field	Value
Publication number	US-10280329-B2
Application number	US-201615045257-A
Country	US
Kind code	B2
Filing date	Feb 17, 2016
Priority date	Mar 31, 2015
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

The present invention provides a pigment dispersion and a method of producing the pigment dispersion. The pigment dispersion includes: water; a pigment; a pigment dispersing polymer; and a rosin acid that includes at least one selected from the group consisting of abietic acid, salts of abietic acid, dihydroabietic acid and salts of dihydroabietic acid, and a total content of abietic acid, salts of abietic acid, dihydroabietic acid and salts of dihydroabietic acid is 50% by mass or higher with respect to a total mass of the rosin acid contained in the pigment dispersion. The pigment dispersion is excellent in terms of dispersibility, storage stability after dispersion, and jettability when used for an inkjet recording ink.

First claim

What is claimed is:

1. A pigment dispersion comprising:
water;
a pigment;
a pigment dispersing polymer; and
a rosin acid that includes at least one selected from the group consisting of abietic acid, salts of abietic acid, dihydroabietic acid and salts of dihydroabietic acid;
wherein a total content of abietic acid, salts of abietic acid, dihydroabietic acid and salts of dihydroabietic acid is 50% by mass or higher with respect to a total mass of the rosin acid contained in the pigment dispersion, and
wherein a ratio of a total content of dihydroabietic acid and salts of dihydroabietic acid relative to a total content of abietic acid and salts of abietic acid (total content of dihydroabietic acid and salts of dihydroabietic acid/total content of abietic acid and salts of abietic acid) is in a range of from 0.1 to 1.0 based on mass, and
wherein the pigment dispersing polymer is selected from the group consisting of a (meth)acrylic acid/benzyl (meth)acrylate copolymer, a (meth)acrylic acid/phenoxyethyl (meth)acrylate copolymer, and a copolymer of (meth)acrylic acid/phenoxyethyl (meth)acrylate/(meth)acrylate having an alkyl group having from 1 to 20 carbon atoms, and
wherein a content of the rosin acid is in a range of from 0.25% by mass to 30.0% by mass with respect to a total mass of the pigment.

2. The pigment dispersion according to claim 1 , wherein a content of the rosin acid is in a range of from 0.25% by mass to less than 3.0% by mass with respect to a total mass of the pigment.

3. The pigment dispersion according to claim 1 , wherein the total content of abietic acid, salts of abietic acid, dihydroabietic acid and salts of dihydroabietic acid is in a range of from 60% by mass to 95% by mass with respect to the total mass of the rosin acid.

4. The pigment dispersion according to claim 1 , wherein the pigment dispersing polymer comprises a hydrophilic structural unit and a hydrophobic structural unit.

5. The pigment dispersion according to claim 1 , wherein the total content of abietic acid, salts of abietic acid, dihydroabietic acid and salts of dihydroabietic acid is in a range of from 60% by mass to 95% by mass with respect to the total mass of the rosin acid.

6. The pigment dispersion according to claim 1 , wherein an acid value of the pigment dispersing polymer is in a range of from 90 mgKOH/g to 150 mgKOH/g.

7. The pigment dispersion according to claim 1 , wherein a pH of the pigment dispersion is in a range of from 8.0 to 9.5.

8. The pigment dispersion according to claim 5 , wherein an acid value of the pigment dispersing polymer is in a range of from 90 mgKOH/g to 150 mgKOH/g, and a pH of the pigment dispersion is in a range of from 8.0 to 9.5.

9. The pigment dispersion according to claim 1 , wherein the pigment dispersing polymer comprises a cross-linked structure.

10. The pigment dispersion according to claim 8 , wherein the pigment dispersing polymer comprises a cross-linked structure.

11. The pigment dispersion according to claim 1 , wherein the pigment dispersion is used for an inkjet recording ink.

12. The pigment dispersion according to claim 1 , wherein the salts of abietic acid is calcium salts of abietic acid, and the salts of dihydroabietic acid is calcium salts of dihydroabietic acid.

13. A method of producing a pigment dispersion, the method comprising:
a mixing process of mixing water, a pigment, a pigment dispersing polymer selected from the group consisting of a (meth)acrylic acid/benzyl (meth)acrylate copolymer, a (meth)acrylic acid/phenoxyethyl (meth)acrylate copolymer, and a copolymer of (meth)acrylic acid/phenoxyethyl (meth)acrylate/(meth)acrylate having an alkyl group having from 1 to 20 carbon atoms, and a rosin acid including at least one selected from the group consisting of abietic acid, salts of abietic acid, dihydroabietic acid, and salts of dihydroabietic acid, to obtain a mixture liquid, in which a total content of abietic acid, salts of abietic acid, dihydroabietic acid, and salts of dihydroabietic acid is 50% by mass or higher, with respect to a total content of the rosin acid, in which a ratio of a total content of dihydroabietic acid and salts of dihydroabietic acid relative to a total content of abietic acid and salts of abietic acid (total content of dihydroabietic acid and salts of dihydroabietic acid/total content of abietic acid and salts of abietic acid) is in a range of from 0.1 to 1.0 based on mass, and in which a content of the rosin acid is in a range of from 0.25% by mass to 30.0% by mass with respect to a total mass of the pigment; and
a dispersion process of subjecting the mixture liquid obtained in the mixing process to a dispersion treatment, to obtain a dispersion.

14. The method of producing a pigment dispersion according to claim 13 , wherein an amount of the rosin acid contained in the mixture liquid obtained in the mixing process is 3.0% by mass or more and 30.0% by mass or less, with respect to a mass of the pigment.

15. The method of producing a pigment dispersion according to claim 13 , wherein the mixing process comprises:
a first process of mixing at least the pigment and the rosin acid including at least one selected from the group consisting of abietic acid, salts of abietic acid, dihydroabietic acid, and salts of dihydroabietic acid, to obtain a first liquid; and
a second process of mixing the pigment dispersing polymer and the first liquid obtained in the first process, to obtain a second liquid.

16. The method of producing a pigment dispersion according to claim 13 , further comprising a pH adjusting process that adjusts a pH of the mixture liquid obtained in the mixing process to 8.0 or more and 9.5 or less by using a water solution containing a monovalent alkali metal.

17. The method of producing a pigment dispersion according to claim 13 , further comprising a reducing process that reduces an amount of the rosin acid in the dispersion obtained in the dispersion process to less than 3.0% by mass with respect to a total mass of the pigment.

18. The method of producing a pigment dispersion according to claim 15 , further comprising:
a pH adjusting process that adjusts a pH of the mixture liquid obtained in the mixing process to 8.0 or more and 9.5 or less by using a water solution containing a monovalent alkali metal; and
a reducing process that reduces an amount of the rosin acid in the dispersion obtained in the dispersion process to less than 3.0% by mass with respect to a total mass of the pigment.

Assignees

• Fujifilm Corp

Inventors

• Nishimura Naoko

Classifications

• C09D11/326 Primary

  characterised by the pigment dispersant · CPC title

• C09D11/38

  characterised by non-macromolecular additives other than solvents, pigments or dyes · CPC title

• C09D11/107

  from unsaturated acids or derivatives thereof · CPC title

• C09D133/10 Primary

  Homopolymers or copolymers of methacrylic acid esters · CPC title

• C09D17/001

  in aqueous medium (C09D17/003, C09D17/004 take precedence) · CPC title