申请人:——
公开号:US20020195022A1
公开(公告)日:2002-12-26
A method for dispersing a pigment in an aqueous solution is provided. The method comprises: (a) providing the pigment, which is distinguished in having an azo group and either a &bgr;-diketo structure or a hydroxyl group, each conjugatively associated with the azo group; (b) treating a surface of the pigment with a base having sufficient strength (e.g., a pK
a
of at least 6) to generate a negative charge on the pigment; and (c) reacting the negatively charged pigment with either (1) a first hydrophilic molecule containing at least one functional group comprising a carbon-carbon double bond and a carbonyl that is alpha to the carbon-carbon double bond which reacts via addition to form a hydrophilic group on the pigment or (2) a second hydrophilic molecule containing at least one functional group selected from the group consisting of anionic functional groups, cationic functional groups, and zwitterionic functional groups and at least one suitable leaving group which reacts via substitution to form a hydrophilic group on the pigment. The treated pigment is rendered comparatively soluble in water-based inks, thereby eliminating the need for any dispersant to disperse the pigment.
本发明提供了一种在水溶液中分散颜料的方法。该方法包括:(a) 提供颜料,该颜料的特点是具有偶氮基团和与偶氮基团共轭的&bgr;-二酮结构或羟基;(b) 用具有足够强度(例如 pK
a
至少为 6)的碱处理颜料表面,使颜料带上负电荷;(c) 将带负电荷的颜料与以下两种亲水分子中的一种反应:(1) 第一种亲水分子,该分子含有至少一个由碳碳双键和碳碳双键上的α-羰基组成的官能团,该官能团通过加成反应在颜料上形成亲水基团;或 (2) 第二种亲水分子,该分子含有至少一个选自阴离子官能团、阳离子官能团和z 离子官能团组成的组的官能团、阳离子官能团和齐聚物官能团中选出的至少一种官能团和至少一种合适的离去基团,它们通过取代反应在颜料上形成亲水基团。经过处理的颜料可相对溶于水性油墨,因此无需使用任何分散剂来分散颜料。