| 摘要 |
<p>PURPOSE:To obtain the subject ink which can give writing with a metallic gloss even after a long-term storage by mixing an aluminum powder with a water-soluble dye and water and lowering the content of inorganic salts to a specified value. CONSTITUTION:This ink composition essentially consists of an aluminum powder as a metallic powder pigment, a water-soluble dye, a resin, a water-soluble organic solvent and water, and has a content of inorganic salts of 0.5wt.% or below. When the ink composition has a content of inorganic salts of above 0.5wt.% and it is stored for a long time, the aluminum powder is deteriorated, and therefore, the metallic gloss of writing is lost or the writing is discolored. Agglomeration among aluminum powder particles occurs, and the aluminum powder is settled. An effective means for lowering the content of inorganic salts to 0.5wt.% or below is to lower the content of inorganic salts in the water- soluble dye which is the main source of contamination with inorganic salts.</p> |
