Calcium-Binding Polymers for Inkjet Pigment Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inkjet printing of pigment-based inks faces challenges with slow pigment aggregation on substrates like plain and coated papers, leading to subpar image quality and stability issues due to low optical density and mottle, particularly with calcium and magnesium salts.
Innovation Solution
Development of polymers comprising ethylenically unsaturated hydrophobic monomers and maleic anhydride or maleic acid derivatives, which are functionalized with organic groups having a calcium index value greater than that of phenylphosphonic acid, to enhance pigment dispersion stability and aggregation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional pigment-based inkjet inks are used, then the ink can be deposited on substrates, but pigment aggregation is slow leading to low optical density and poor image quality
Solution Approach 1:
The patent modifies the chemical parameters of the ink composition by incorporating specific polymers with calcium-binding functional groups (such as carboxylic acids, phosphonic acids, and hydroxyl groups). These polymers have specific molecular weights and compositional ratios that enable rapid calcium ion binding, thereby accelerating pigment aggregation kinetics and improving image quality metrics like optical density and mottle.
Solution Approach 2:
The patent introduces polymers as intermediary substances that mediate between the pigment particles and calcium ions in the substrate. These polymers contain multiple binding sites that simultaneously interact with pigment surfaces and calcium ions, facilitating rapid pigment aggregation through a bridging mechanism that enhances both aggregation speed and image quality.
2Stability of the object's composition
If pigment dispersions are stabilized for storage, then stability is improved, but upon contact with substrate the aggregation process remains slow
Solution Approach 1:
The patent employs polymers with dynamic conformational flexibility that allow them to adapt their structure based on environmental conditions. In storage conditions, these polymers maintain pigment dispersions in a stable, dispersed state. Upon contact with the substrate and calcium ions, the polymers dynamically reconfigure to facilitate rapid aggregation, thus achieving both stability during storage and rapid aggregation during printing.
Solution Approach 2:
The patent incorporates polymers that are pre-functionalized with calcium-binding groups before ink application. These polymers are prepared in advance with the specific capability to rapidly bind calcium ions, so that when the ink contacts the substrate, the aggregation process can immediately proceed at high speed without requiring induction time.
3Speed
If polymers with calcium-binding groups are added to accelerate aggregation, then aggregation speed improves, but dispersion stability may be compromised
Solution Approach 1:
The patent designs polymers with heterogeneous functional group distribution, where calcium-binding groups (such as carboxylic acid or phosphonic acid groups) are localized at specific positions along the polymer chain, while other portions of the polymer provide steric stabilization. This local differentiation allows the polymer to simultaneously enable rapid calcium binding for fast aggregation while maintaining overall dispersion stability through the stabilizing portions.
Solution Approach 2:
The patent utilizes composite polymer structures that combine multiple functional moieties within a single macromolecule. These composite polymers integrate calcium-binding functional groups with hydrophobic/hydrophilic segments and steric barriers, creating a multifunctional material that can both accelerate aggregation through calcium binding and maintain dispersion stability through combined steric and electrostatic stabilization mechanisms.
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 polymers improve printing performance by rapidly destabilizing dispersions upon contact with substrates, resulting in images with better optical density, edge acuity, and reduced intercolor bleed, thereby addressing the stability and quality issues in inkjet ink compositions.
Implementation Method 1
polymers comprising ethylenically unsaturated hydrophobic monomers and maleic anhydride and/or maleic acid (or salts, esters, imides, and amides thereof) monomers, wherein at least one portion of the second monomers is functionalized with at least one organic group having a calcium index value greater than a calcium index value of phenylphosphonic acid
Data Source
AI summary
Disclosed herein are polymers, which can be incorporated in pigment dispersions and inkjet ink compositions, comprising first monomers selected from ethylenically unsaturated hydrophobic monomers, and second monomers selected from maleic anhydride, maleic acid, and salts, esters, imides, and amides thereof. The polymers can have a portion of the second monomers functionalized with at least one organic group having a calcium index value greater than or equal to a calcium index value of phenylphosphonic acid. Additionally and/or alternatively, the at least one polymer can be crosslinked via the second monomers. Dispersions and inkjet ink compositions comprising such polymers can also further comprise at least one pigment and a liquid vehicle. Also disclosed are methods of making such polymers.