WATER-SOLUBLE NAPHTHALOCYANINE DYE AND AQUEOUS INK CONTAINING THE SAME

摘要

Disclosed is an aqueous solution composition (aqueous ink composition) containing a water-soluble naphthalocyanine dye represented by the formula (1) below or a salt thereof. Also disclosed is a novel naphthalocyanine dye. The compound has high absorption in the near-infrared region, and is thus useful as a near-infrared absorbent. In addition, the compound is excellent in storage stability in the form of an aqueous solution, it is useful as a near-infrared absorbing aqueous ink. (1) (In the formula, M represents a hydrogen atom, a metal atom, a metal oxide, a metal hydroxide or a metal halide; X represents a carbonyl group or a sulfonyl group; W1-W4 independently represent a hydrogen atom, an ionic hydrophilic group or the like, and at least one of W1-W4 represents a group other than a hydrogen atom; and n represents an integer of 1-24.)