Water-based ink for ink-jet recording and ink cartridge

Patent metadata

Field	Value
Publication number	US-9732247-B2
Application number	US-201615240564-A
Country	US
Kind code	B2
Filing date	Aug 18, 2016
Priority date	Sep 30, 2015
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A water-based ink for ink-jet recording includes: a self-dispersible pigment having an anionic group; water; a water-soluble resin; and an anionic surfactant, wherein the water-soluble resin is an ABA-type triblock copolymer which has a polymer block A composed only of methyl methacrylate and methacrylic acid and a polymer block B composed only of benzyl methacrylate and methacrylic acid; which has a weight average molecular weight of 3,000 to 30,000; which has an acid value of 90 mgKOH/g to 200 mgKOH/g; and which is partially or completely neutralized.

First claim

What is claimed is:

1. A water-based ink for ink-jet recording comprising:
a self-dispersible pigment having an anionic group;
water;
a water-soluble resin; and
an anionic surfactant,
wherein the water-soluble resin is an ABA-type triblock copolymer which has a polymer block A composed only of methyl methacrylate and methacrylic acid and a polymer block B composed only of benzyl methacrylate and methacrylic acid;
which has a weight average molecular weight of 3,000 to 30,000; which has an acid value of 90 mgKOH/g to 200 mgKOH/g; and which is partially or completely neutralized.

2. The water-based ink for ink-jet recording according to claim 1 , wherein the anionic surfactant is a compound represented by the following formula (1):

in the formula (1),
R 1 is an alkyl group;
R 2 is an ethylene group or a propylene group;
n is an integer in a range of 0 to 10; and
M is alkali metal, alkali earth metal, ammonium, or alkanolamine.

3. The water-based ink for ink-jet recording according to claim 1 , wherein the anionic surfactant is a compound represented by the following formula (1):

in the formula (1),
R 1 is an alkyl group having 8 to 18 carbon atoms;
R 2 is an ethylene group;
n is an integer in a range of 1 to 10; and
M is sodium, potassium, or ammonium.

4. The water-based ink for ink-jet recording according to claim 1 , wherein a weight ratio of a blending amount of the anionic surfactant in the water-based ink to a blending amount of the water-soluble resin in the water-based ink is in a range of 1 to 5.

5. The water-based ink for ink-jet recording according to claim 1 , wherein the water-based ink contains the water-soluble resin in a range of 0.04% by weight to 1% by weight.

6. The water-based ink for ink-jet recording according to claim 1 , wherein the water-based ink contains the anionic surfactant in a range of 0.04% by weight to 1.5% by weight.

7. The water-based ink for ink-jet recording according to claim 1 , wherein a weight ratio of a blending amount of the self-dispersible pigment having the anionic group in the water-based ink to a blending amount of the water-soluble resin in the water-based ink is in a range of 2 to 300.

8. The water-based ink for ink-jet recording according to claim 1 , wherein a weight ratio of a blending amount of the self-dispersible pigment having the anionic group in the water-based ink to a total blending amount of the water-soluble resin and the anionic surfactant in the water-based ink is in a range of 1 to 160.

9. The water-based ink for ink-jet recording according to claim 1 , wherein a ratio of a weight average molecular weight of the polymer block A to a weight average molecular weight of the polymer block B is in a range of 0.2 to 8.

10. The water-based ink for ink-jet recording according to claim 1 , wherein a weight ratio of the methyl methacrylate to the methacrylic acid in the polymer block A is in a range of 1.7 to 3.8; and
a weight ratio of the benzyl methacrylate to the methacrylic acid in the polymer block B is in a range of 3.8 to 32.0.

11. The water-based ink for ink-jet recording according to claim 1 , wherein the ABA-type triblock copolymer is neutralized by potassium hydroxide.

12. The water-based ink for ink-jet recording according to claim 1 , wherein the self-dispersible pigment having the anionic group is self-dispersible carbon black modified by a carboxylic acid group, self-dispersible carbon black modified by a sulfonic acid group, or self-dispersible carbon black modified by a phosphoric acid group.

13. The water-based ink for ink-jet recording according to claim 1 , further comprising glycerol and triethylene glycol-n-butyl ether.

14. An ink cartridge, comprising the water-based ink for ink-jet recording as defined in claim 1 .

Assignees

• Brother Ind Ltd

Inventors

• Yamashita Narumi
• Tanaka Hiroyuki

Classifications

• C09D11/106

  containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C09D11/30 Primary

  Inkjet printing inks · CPC title

• C09D11/107

  from unsaturated acids or derivatives thereof · CPC title

• C09D11/322

  Pigment inks · CPC title

• C08F287/00

  Macromolecular compounds obtained by polymerising monomers on to block polymers · CPC title