Pigment dispersing agent, pigment composition and pigment dispersion

A pigment dispersing agent represented by the formula (1),

• Q represents a quinophthalone residue or a substituted quinophthalone residue,
• X1 represents a group selected from the group consisting of NR′SO2—, —SO2NR′—, —CONR′—, —CH2NR′COCH2NR′— and —NR′CO—,
• X2 represents at least one group selected from the group consisting of an arylene group having 20 or less carbon atoms, a substituted arylene group having 20 or less carbon atoms, a heteroaromatic ring having 20 or less carbon atoms, and a substituted heteroaromatic ring having 20 or less carbon atoms, or at least two groups which are selected from the group consisting of an arylene group having 20 or less carbon atoms a substituted arylene group having 20 or less carbon atoms, a heteroaromatic ring having 20 or less carbon atoms, and a substituted heteroaromatic ring having 20 or less carbon atoms and heteroaromatic rings and are bonded to each other with a divalent connecting group selected from the group consisting of —NR′—, —O—, —SO2— and —CO—,
• X3 represents —NR′— or —O—, where R′ represents a hydrogen atom, an alkyl group having 20 or less carbon atoms, a substituted alkyl group having 20 or less carbon atoms, an alkenyl group having 20 or less carbon atoms, a substituted alkenyl group having 20 or less carbon atoms, an aryl group having 20 or less carbon atoms or a substituted aryl group having 20 or less carbon atoms,
• each of A and B independently represents a group selected from a group represented by the formula (2) or the formula (3), —O—(CH2)n—R8, —OR9, —NR10R11, —Cl, —F or —X3—X2—X1-Q, where R8 represents a nitrogen-containing heterocyclic residue or a substituted nitrogen-containing heterocyclic residue, each of R9, R10 and R11 independently represents a hydrogen atom, an alkyl group having 20 or less carbon atoms, a substituted alkyl group having 20 or less carbon atoms, an alkenyl group having 20 or less carbon atoms, a substituted alkenyl group having 20 or less carbon atoms, an aryl group having 20 or less carbon atoms or a substituted aryl group having 20 or less carbon atoms, and n is an integer of 0 to 20, provided that at least one of A and B is a group represented by the formula (2) or the formula (3), —O—(CH2)n—R8, —OR9 or —NR10R11, and
• t is an integer of 1 to 3,
• wherein
• Y1 represents —NR′— or —O—,
• Y2 represents at least one group selected from the group consisting of an alkylene group having 20 or less carbon atoms, a substituted alkylene group having 20 or less carbon atoms, an alkenylene group having 20 or less carbon atoms, a substituted alkenylene group having 20 or less carbon atoms, an arylene group having 20 or less carbon atoms and a substituted arylene group having 20 or less carbon atoms, or at least two groups which are selected from these alkylene groups, alkenylene groups and arylene groups and are bonded to each other with a divalent connecting group selected from the group consisting of —NR′—, —O—, —SO2— and —CO—, where R′ is as defined in the formula (1), and
• each of R1 and R2 independently represents an alkyl group having 20 or less carbon atoms, a substituted alkyl group having 20 or less carbon atoms, an alkenyl group having 20 or less carbon atoms or a substituted alkenyl group having 20 or less carbon atoms, or R1 and R2 together form a heterocyclic structure which can contain a nitrogen atom, an oxygen atom or a sulfur atom or a substituted heterocyclic structure which can contain a nitrogen atom, an oxygen atom or a sulfur atom,
• wherein
• Z1 is a single bond or represents —NR′—, —NR′-G-CO—, —NR′-G-CONR″—, —NR′-G-SO2—, —NR′-G-SO2NR″—, —O-G-CO—, —O-G-CONR′—, —O-G-SO2— or —O-G-SO2NR′—, where G represents an alkylene group having 20 or less carbon atoms, a substituted alkylene group having 20 or less carbon atoms, an alkenylene group having 20 or less carbon atoms, a substituted alkenylene group having 20 or less carbon atoms, an arylene group having 20 or less carbon atoms or a substituted arylene group having 20 or less carbon atoms, and each of R′ and R″ independently represents a hydrogen atom, an alkyl group having 20 or less carbon atoms, a substituted alkyl group having 20 or less carbon atoms, an alkenyl group having 20 or less carbon atoms, a substituted alkenyl group having 20 or less carbon atoms, an aryl group having 20 or less carbon atoms or a substituted aryl group having 20 or less carbon atoms,
• each of R3, R4, R5 and R6 independently represents a hydrogen atom, an alkyl group having 20 or less carbon atoms, a substituted alkyl group having 20 or less carbon atoms, an alkenyl group having 20 or less carbon atoms, a substituted alkenyl group having 20 or less carbon atoms, an aryl group having 20 or less carbon atoms or a substituted aryl group having 20 or less carbon atoms, and
• R7 represents an alkyl group having 20 or less carbon atoms, a substituted alkyl group having 20 or less carbon atoms, an alkenyl group having 20 or less carbon atoms or a substituted alkenyl group having 20 or less carbon atoms.