| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an oil-base red ink improved in long-term stability by mixing a specified red dye with a yellow dye, an aliphatic alcohol and a resin soluble therein. SOLUTION: An aqueous solution of basic dye is mixed under agitation with an aqueous solution of an acid dye, a direct dye or anionic surfactant, and the insoluble reaction product is separated by filtration, washed with water and dried to obtain a red dye of formula I (wherein R1 is H or methyl; R2 is H or a 1 or 2C alkyl; and A is an acid dye, a direct dye or an anionic surfactant or Cl). 2-15wt.% this dye is mixed under agitation with 0.2-10wt.% yellow dye of formula II (wherein R3 is an 8-18c alkyl), 40-90wt.% 4C or lower aliphatic alcohol and 1-20wt.% resin soluble in this alcohol to obtain an oil-base red ink which does not undergo dye precipitation even in a low-temperature long- term storage test, which include conditions favorable for dye precipitation, and therefore can give dense writing without skipping.</p> |
