Pigment dispersion, and ink composition, curable composition and curable ink composition produced with pigment dispersion

• US 8,293,837 B2
• Filed: 03/02/2010
• Issued: 10/23/2012
• Est. Priority Date: 03/23/2009
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Shimohara, Norihide
• Primary Examiner(s): SASTRI, SATYA B
• Application Number:
  US12/715,413
• Publication Number:
  US 20100240825A1
• Time in Patent Office: 966 Days
• Field of Search: 524/589, 524/590, 523/160, 523/161
• US Class Current: 524/589
• CPC Class Codes: C08G 18/3215 containing aromatic groups or benzoquinone groups
• CPC Class Codes: C08G 18/3293 containing heterocyclic groups
• CPC Class Codes: C08G 18/4277 Caprolactone and/or substituted caprolactone
• CPC Class Codes: C08G 18/4676 containing sulfur
• CPC Class Codes: C08G 18/622 Polymers of esters of alpha-beta ethylenically unsaturated carboxylic acids
• CPC Class Codes: C08G 18/6511 compounds of group C08G18/3203
• CPC Class Codes: C08G 18/664 with compounds of group C08G18/3203
• CPC Class Codes: C08G 18/794 formed by oligomerisation of aromatic isocyanates or isothiocyanates
• CPC Class Codes: C09D 11/101 Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
• CPC Class Codes: C09D 11/326 characterised by the pigment dispersant
• CPC Class Codes: C09D 17/003 containing an organic pigment process features in the making of dye stuff preparations C09B67/00

Abstract

The present invention provides a pigment dispersion, including: (a) a pigment; and (b) a polymer compound as a dispersant for the pigment (a), wherein the polymer compound includes a urethane bond in a main chain, includes a pendant moiety containing a skeleton which is the same as a partial skeleton of the pigment (a), and further includes, at a side chain, at least one polymer chain selected from the group consisting of a polyester chain, a poly(meth)acrylate chain, and a polyalkylene oxide chain, and wherein the molecular weight of the skeleton which is the same as a partial skeleton of the pigment (a) is from 20 to 70% of the molecular weight of the pigment (a).

Claims

1. A pigment dispersion, comprising:

(a) a pigment; and

(b) a polymer compound as a dispersant for the pigment (a),

wherein the polymer compound comprises a urethane bond in a main chain, comprises a pendant moiety comprising a skeleton which is the same as a partial skeleton of the pigment (a), and further comprises, at a side chain, at least one polymer chain selected from the group consisting of a polyester chain, a poly(meth)acrylate chain, and a polyalkylene oxide chain,

wherein the molecular weight of the skeleton which is the same as a partial skeleton of the pigment (a) is from 20 to 70% of the molecular weight of the pigment (a), and

wherein the skeleton which is the same as a partial skeleton of the pigment (a) is a fused ring structure consisting of two or more rings.

2. The pigment dispersion according to claim 1, wherein the weight average molecular weight of the polymer compound is from 5,000 to 200,000.

3. The pigment dispersion according to claim 1, wherein the average particle diameter of the pigment is from 0.01 μ

m to 0.4 μ

m.

4. The pigment dispersion according to claim 1, wherein the pigment is included in the pigment dispersion at an amount of from 1 to 40% by weight with respect to the total solid content of the pigment dispersion.

5. An ink composition, comprising the pigment dispersion according to claim 1.

6. A curable composition, comprising the pigment dispersion according to claim 1 and (c) a polymerizable compound.

7. A curable ink composition, comprising the curable composition according to claim 6.

8. A method for manufacturing the pigment dispersion according to claim 1, the method comprising:

preparing the polymer compound by reacting

(i) a derivative having one or two hydroxyl groups or one or two isocyanate groups, and having a skeleton that is the same as a partial skeleton of the pigment,

(ii) one of a polyester having one or two hydroxyl groups at the terminal, a poly(meth)acrylate having one or two hydroxyl groups at the terminal or a polyalkylene oxide having one or two hydroxyl groups at the terminal, and

(iii) a bifunctional or polyfunctional isocyanate compound; and

dispersing the pigment and the polymer compound.

9. The pigment dispersion according to claim 1, wherein a combination of the pigment and the skeleton which is the same as a partial skeleton of the pigment is selected from the group of combinations consisting of:

an acetolone pigment or a naphtholone pigment with a benzimidazolone structure;

a quinacridone pigment with an acridone structure;

a perylene pigment with a phthalimide structure;

an anthraquinone pigment with an anthraquinone structure;

a naphthol AS pigment with an azo substituent-free naphthalene structure; and

a dioxazine violet pigment with a carbazole structure.