| 摘要 |
<p>A process is provided for reducing the crusting propensity of dyes, complexed with sodium or other cations, used in ink-jet print heads and for improving other properties of such dyes. The process comprises replacing at least a portion of the cations on such dyes with preselected cations, such as those of the alkali metals lithium, potassium, ammonium, and amines. A two-step process may be used, in which the sodium cations first are at least partially replaced with hydrogen cations by passing an aqueous solution of the dye through the hydrogen form of a strong acid ion exchange resin and the hydrogen cations subsequently are at least partially replaced with the preselected cations by neutralizing the hydrogen-containing dye solution with a base which contains the preselected cation species. Alternately, a one-step process, comprising passing the aqueous solution of the dye through an ion-exchange resin pre-loaded with the preselected cations may be employed.</p> |
