Ink Jet Ink Polymer Stabilizes Pigment Dispersion
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Solution Overview
Problem
Ink jet systems face challenges in stably ejecting ink containing pigments with secondary amino groups due to ionic bonding with negatively charged liquid-contact members, leading to clogging and instability in continuous ejection.
Innovation Solution
Incorporating a polymer with a ring structure containing a tertiary amino group into the ink, which reduces electrostatic interactions and prevents accumulation, allowing for stable ejection by forming a protective layer and maintaining the pigment in a dispersed state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pigment having a secondary amino group is used as a coloring material, then the ink can provide good coloring performance, but ionic bonding occurs with liquid-contact members causing clogging and unstable ejection
Solution Approach 1:
A polymer dispersant with a specific structure (polycarboxylate type with controlled molecular weight and composition) is introduced as an intermediary between the pigment and the liquid-contact member. This dispersant adsorbs onto the pigment surface and provides steric stabilization, preventing direct ionic bonding between the secondary amino group of the pigment and the negatively charged liquid-contact member, thereby eliminating clogging while preserving coloring performance
2Stability of the object's composition
If a water-soluble polymer is used as a dispersant, then the ink can be formulated in aqueous medium, but the polymer has poor solubility and cannot stably disperse the pigment
Solution Approach 1:
The molecular weight, composition, and structure of the polymer dispersant are precisely controlled within specific ranges. The dispersant is designed with a polycarboxylate backbone and specific side chain structures that provide optimal balance between water solubility and pigment binding affinity, enabling stable dispersion without requiring excessive polymer concentration
3Reliability
If a polymer with ring structure containing tertiary amino group is used, then electrostatic interactions are reduced and continuous ejection is stabilized, but the device complexity increases
Solution Approach 1:
The polymer dispersant incorporates a ring structure containing a tertiary amino group at specific locations along the polymer chain, rather than uniformly throughout. This localized structural feature provides the necessary electrostatic interaction modulation and steric stabilization, achieving stable continuous ejection while maintaining relatively simple overall ink composition
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 polymer with a tertiary amino group ring structure enhances the stability of ink ejection by minimizing ionic bonding with the liquid-contact members, preventing clogging and ensuring continuous, stable ink droplet formation.
Implementation Method 1
a polymer containing a unit derived from a monomer having a ring structure containing a tertiary amino group... reduces electrostatic interactions and prevents accumulation
Implementation Method 2
forming a protective layer and maintaining the pigment in a dispersed state
Implementation Method 3
stabilizing the dispersion... dispersing the pigment in the dispersion medium
Data Source
AI summary
An ink jet ink including water, a pigment and a polymer. The pigment has a secondary amino group. The polymer contains a unit derived from a monomer having a ring structure containing a tertiary amino group.