Pigment dispersion liquid, ink jet recording ink, ink jet recording method, ink cartridge and ink jet recording apparatus
A pigment dispersion liquid capable of stably recording images having high fastness and excellent quality for a long term in any cases has been provided. A pigment dispersion liquid mainly containing a polymer dispersant, a pigment and water, wherein the polymer dispersant is a copolymer comprised of at least a hydrophobic unit and a hydrophilic unit, the hydrophobic unit has a block portion comprised of at least one hydrophobic monomer, the hydrophilic unit has at least a repeating unit structure of an acrylamide structure of the following general formula (1), and the segment number (A) of the block portion comprised of a hydrophobic monomer to the number (B) of all segments of the polymer dispersant is in a range of 0.07 to 0.85 in terms of A/B ratio.
1. A pigment dispersion liquid mainly comprising a polymer dispersant, a pigment and water, wherein the polymer dispersant is a copolymer comprised of at least a hydrophobic unit and a hydrophilic unit, the hydrophobic unit has a block portion comprised of at least one hydrophobic monomer, the hydrophilic unit has at least a repeating unit structure of an acrylamide structure of the following general formula (1), and wherein the segment number (A) of the block portion comprised of a hydrophobic monomer to the number (B) of all segments of the polymer dispersant is in a range of 0.07 to 0.85 in terms of A/B ratio:
wherein, R 1 represents a hydrogen atom or a methyl group, X represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms and n is 1 to 10.
2. The pigment dispersion liquid according to claim 1 , wherein the block portion comprised of a hydrophobic monomer in the hydrophobic unit is a block portion comprised of a repeating unit structure of the following general formula (2):
wherein, R 2 represents a hydrogen atom or a methyl group and Y represents —R 3 , —OR 3 or —COOR 3 where R 3 represents an alkyl group having 1 to 18 carbon atoms.
3. The pigment dispersion liquid according to claim 1 , wherein the hydrophilic unit has a segment having an anionic hydrophilic group.
4. The pigment dispersion liquid according to claim 3 , wherein the hydrophilic unit has a block portion comprised of a repeating unit structure of the general formula (1) and a block portion comprised of a segment having an anionic hydrophilic group.
5. The pigment dispersion liquid according to claim 4 , wherein the polymer dispersant is comprised of at least a block portion comprised of a repeating unit structure of the general formula (2), a block portion comprised of a repeating unit structure of the general formula (1) and a block portion comprised of a segment having an anionic hydrophilic group in the stated order.
6. The pigment dispersion liquid according to claim 1 , wherein the segment number (A) of the block portion comprised of a hydrophobic monomer of the polymer dispersant to the segment number (C) of the general formula (1) of the polymer dispersant is in a range of 0.1 to 20 in terms of A/C ratio.
7. An ink jet recording ink prepared by mixing a pigment dispersion liquid as set forth in claim 1 and at least a water-soluble organic solvent.
8. An ink jet recording method comprising causing an ink to fly by applying energy to the ink to apply the ink to a recording material, wherein the ink is an ink jet recording ink according to claim 7 .
9. The ink jet recording method according to claim 8 , wherein the energy is a thermal energy.
10. An ink cartridge having an ink storage portion containing an ink, wherein the ink is an ink jet recording ink according to claim 7 .
11. An ink jet recording apparatus having an ink cartridge having an ink storage portion containing an ink and a head portion for ejecting the ink, wherein the ink is an ink jet recording ink according to claim 7 .