Pigment dispersion, and ink composition, curable composition and curable ink composition produced with pigment dispersion
View Patent ↗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).
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 μm to 0.4 μm.
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.