Modified Pigment Diazotization Process for Inkjet Inks
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Solution Overview
Problem
Existing methods for attaching organic groups, particularly those with multiple carboxylic acid groups or salts, to pigments are limited and do not consistently produce modified pigments with optimal performance for applications like inkjet inks.
Innovation Solution
A process involving combining a pigment with an aromatic amine containing vicinal dicarboxylic acid groups, a base, and an aqueous medium, followed by a diazotizing agent, to form modified pigments with attached carboxylic acid salt groups, which are then used in inkjet ink compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods for attaching organic groups to pigments are used, then modified pigments can be produced, but the methods are limited and do not consistently produce modified pigments with optimal performance for inkjet inks
Solution Approach 1:
The patent applies universality by developing a diazotization-based method that can attach various organic groups (including those with multiple carboxylic acid groups) to different pigment types, making the process broadly applicable across pigment classes rather than requiring pigment-specific methods
Solution Approach 2:
The patent utilizes parameter changes by controlling the diazotization reaction conditions (such as temperature, pH, and reagent concentrations) to optimize the attachment of organic groups to pigments, thereby improving performance consistency for inkjet ink applications
2Manufacturing precision
If methods relying on inherent pigment functionality are used, then specific functional groups can be attached, but not all pigments have the same specific functional groups
Solution Approach 1:
The patent employs an intermediary approach by using diazotization as a universal coupling mechanism that bridges the pigment surface groups and organic compounds. This intermediary reaction mechanism allows attachment of organic groups to pigments regardless of the specific functional groups present on the pigment surface
Solution Approach 2:
The diazotization method provides universality across different pigment types, enabling the attachment of organic groups containing carboxylic acid salt groups to various pigments (including carbon blacks and colored pigments) without requiring pigment-specific functional groups
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process results in modified pigments with improved properties for inkjet ink compositions, enhancing image quality and stability, as demonstrated by improved optical density and reduced mottle and edge acuity in printed images.
Implementation Method 1
combining the mixture and a diazotizing agent to form the modified pigment
Data Source
AI summary
A process for preparing a modified pigment having attached at least one organic group is described. This process comprises the step of combining, in any order, a colored pigment, an aromatic amine, a base, and an aqueous medium to form a mixture, and then combining the mixture and a diazotizing agent to form the modified pigment. The aromatic amine comprises at least two carboxylic acid groups, preferably being vicinal. The resulting modified colored pigment can be used in an inkjet ink composition to produce printed images having good overall properties.