| 摘要 |
<p>PURPOSE: To obtain an oil-base blue ink composition improved in long-term solution stability, light fastness of writing, water resistance and dye fixation by using a specified triphendioxazine dye salt. CONSTITUTION: A triphendioxazine dye base obtained for example by condensing 2,4-diaminobenzenesulfonic acid with chloranil in the presence of magnesium oxide as an acid binder and effecting the ring opening of the condensate with sulfuric acid is formed into a 3-5% aqueous solution, hydrochloric acid or acetic acid is added to this solution, the entire mixture is heated to form a solution, this solution is filtered, a 3-5% aqueous solution of an organic acid being a 3-20 C anionic surfactant is added thereto dropwise and reacted, the pH of the reaction solution is adjusted to 4-7, the mixture is heated to form coarse particles, and these particles are filtered off, washed with water and dried. The thus obtained triphendioxazine dye salt represented by formula [Xs are each a cationic group selected from among the groups of formulas II-IV (Rs are each 1-4 C alkyl which may be substituted with hydroxyl or alkoxyl; and m is 1-3), provided that not both of them can be simultaneously -NH3 <+> or -NH2 ; Z is halogen A<-> is an anion of an organic acid; and n is 4 or below] is dissolved in an alcoholic solvent.</p> |
