Colored particle dispersion

Patent metadata

Field	Value
Publication number	US-2018258200-A1
Application number	US-201615753735-A
Country	US
Kind code	A1
Filing date	Aug 23, 2016
Priority date	Aug 24, 2015
Publication date	Sep 13, 2018
Grant date	—

Abstract

The present invention relates to [1] a colored fine particle dispersion containing colored fine particles and a neutralizing agent, in which the colored fine particles are produced by subjecting a monomer mixture containing an acid group-containing polymerizable monomer to emulsion polymerization in the presence of a pigment; the neutralizing agent contains a water-soluble amine compound; and the colored fine particle dispersion has a pH value of from 6 to 11, and [2] a process for producing a colored fine particle dispersion containing colored fine particles and a neutralizing agent, said process including the step 1 of subjecting a monomer mixture containing an acid group-containing polymerizable monomer to emulsion polymerization in the presence of a pigment to obtain a colored fine particle dispersion (p); and the step 2 of mixing the colored fine particle dispersion (p) and the neutralizing agent containing a water-soluble amine compound to obtain the colored fine particle dispersion having a pH value of from 6 to 11. The colored fine particle dispersion of the present invention is used in a water-based ink so that the resulting water-based ink is excellent in ejection stability upon evaporation of water from the ink system while maintaining excellent storage stability thereof, and it is possible to obtain printed materials that are excellent in alcohol resistance even when printed on a low-water absorbing printing medium.

First claim

1 . A colored fine particle dispersion comprising colored fine particles and a neutralizing agent, in which the colored fine particles are produced by subjecting a monomer mixture comprising an acid group-containing polymerizable monomer to emulsion polymerization in the presence of a pigment; the acid group is a carboxy group; the neutralizing agent comprises a water-soluble amine compound; the acid group is neutralized with the water-soluble amine compound; and the colored fine particle dispersion has a pH value of not less than 6 and not more than 11.

2 . The colored fine particle dispersion according to claim 1 , wherein a content of the water-soluble amine compound in the neutralizing agent is not less than 80% by mass.

3 . The colored fine particle dispersion according to claim 1 , wherein the acid group-containing polymerizable monomer is at least one monomer selected from the group consisting of (meth)acrylic acid, maleic acid, itaconic acid, fumaric acid and crotonic acid.

4 . The colored fine particle dispersion according to claim 1 , wherein the monomer mixture further comprises a hydrophobic polymerizable monomer, and the hydrophobic polymerizable monomer is at least one monomer selected from the group consisting of a (meth)acrylate and an aromatic ring-containing hydrophobic monomer.

5 . The colored fine particle dispersion according to claim 1 , wherein the water-soluble amine compound is a compound having not less than 2 and not more than 8 carbon atoms.

6 . The colored fine particle dispersion according to claim 1 , wherein the water-soluble amine compound is an alkanolamine having not less than 2 and not more than 8 carbon atoms.

7 . The colored fine particle dispersion according to claim 1 , wherein the water-soluble amine compound is at least one compound selected from the group consisting of N-dimethylaminoethanol, N-methyldiethanolamine, diethanolamine and triethanolamine.

8 . The colored fine particle dispersion according to claim 1 , wherein the pigment is a pigment subjected to no hydrophilic treatment.

9 . The colored fine particle dispersion according to claim 1 , wherein the colored fine particle dispersion is used in a water-based ink for ink-jet printing.

10 . A process for producing a colored fine particle dispersion comprising colored fine particles and a neutralizing agent, said process comprising the following steps 1 and 2:
Step 1: subjecting a monomer mixture comprising an acid group-containing polymerizable monomer to emulsion polymerization in the presence of a pigment to obtain a colored fine particle dispersion (p); and Step 2: mixing the colored fine particle dispersion (p) and the neutralizing agent comprising a water-soluble amine compound to obtain the colored fine particle dispersion having a pH value of not less than 6 and not more than 11, wherein the acid group is a carboxy group and the acid group is neutralized with the water-soluble amine compound.

11 . The process for producing a colored fine particle dispersion according to claim 10 , wherein the step 1 comprises the following steps 1a and 1b:
Step 1a: dispersing a mixed solution comprising the pigment, a surfactant (a) and water to obtain a pigment dispersion (a): and Step 1b: mixing the pigment dispersion (a) and the monomer mixture comprising the acid group-containing polymerizable monomer and subjecting the resulting mixture to emulsion polymerization to obtain the colored fine particle dispersion (p).

12 . The process for producing a colored fine particle dispersion according to claim 11 , wherein in the step 1a, the mixed solution further comprises an organic solvent (a).

13 . The process for producing a colored fine particle dispersion according to claim 10 , wherein a content of the water-soluble amine compound in the neutralizing agent is not less than 80% by mass.

14 . The process for producing a colored fine particle dispersion according to claim 1 , wherein the water-soluble amine compound is a compound having not less than 2 and not more than 8 carbon atoms.

15 . (canceled)

16 . The colored fine particle dispersion according to claim 1 , wherein a content (solid content) of the colored fine particles in the colored fine particle dispersion is not less than 10% by mass and not more than 60% by mass.

17 . The colored fine particle dispersion according to claim 1 , wherein a content of the acid group-containing polymerizable monomer in the monomer mixture is preferably not less than 1% by mass and not more than 20% by mass.

18 . The colored fine particle dispersion according to claim 4 , wherein the (meth)acrylate is at least one compound selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate and 2-ethylhexyl (meth)acrylate.

19 . The colored fine particle dispersion according to claim 4 , wherein the aromatic ring-containing hydrophobic monomer is at least one monomer selected from the group consisting of a styrene-based monomer and an aromatic group-containing (meth)acrylate.

20 . The colored fine particle dispersion according to claim 4 , wherein a content of the hydrophobic polymerizable monomer in the monomer mixture is not less than 80% by mass and not more than 99% by mass.

21 . The process for producing a colored fine particle dispersion according to claim 11 , wherein the surfactant (a) comprises a polymerizable surfactant.

Assignees

• Kao Corp

Inventors

• Matsumoto Yuuta

Classifications

• B41M5/00

  Duplicating or marking methods; Sheet materials for use therein (by using light-sensitive materials G03; electrography, magnetography G03G {; repeatedly usable boards or tablets for writing or drawing B43L1/00}) · CPC title

• C09D11/326

  characterised by the pigment dispersant · CPC title

• C09D17/00

  Pigment pastes, e.g. for mixing in paints (artists' paints C09D5/06) · CPC title

• C08F2/22

  Emulsion polymerisation · CPC title

• C09D11/322 Primary

  Pigment inks · CPC title