Water-Based Ink Crosslinked Polymer Particles Ejection Stability
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Solution Overview
Problem
Conventional water-based inks for ink-jet printing face issues with non-uniform ink film formation, insufficient ejection stability, and fastness of printed images due to pigment dispersion instability and low acid value of carboxylic acid monomers, leading to poor optical density and rapid flocculation.
Innovation Solution
A water-based ink containing pigment-containing water-insoluble crosslinked polymer particles formed by crosslinking a polymer with a carboxylic acid monomer having an acid value of at least 200 mgKOH/g and a hydrophobic monomer with an epoxy compound, combined with a polymer emulsion containing similar constitutional units, to enhance electrostatic repulsion and steric network structure, improving dispersion stability and optical density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a polymer with low acid value carboxylic acid monomer is used, then the ink formulation is simpler, but the electrostatic repulsion is insufficient leading to rapid flocculation and poor dispersion stability
Solution Approach 1:
The patent changes the acid value parameter of the carboxylic acid monomer from conventional low values to a specific range of 200-400 mg KOH/g. This parameter change enhances the electrostatic repulsion between polymer chains, preventing flocculation and improving dispersion stability without requiring complex additional formulations.
Solution Approach 2:
The patent creates a composite polymer structure combining carboxylic acid monomer units (providing electrostatic repulsion) with hydrophobic monomer units (providing steric network structure). This composite approach achieves both electrostatic and steric stabilization mechanisms simultaneously, resolving the contradiction between simplicity and stability.
2Reliability
If conventional polymer emulsion is used, then the manufacturing process is simpler, but the ejection stability deteriorates after interruption and under severe drying conditions
Solution Approach 1:
The patent performs preliminary crosslinking of the polymer emulsion to form a steric network structure before ink ejection. This preliminary action creates a stable framework that prevents pigment flocculation during ejection interruptions and under severe drying conditions, ensuring reliable ejection stability without requiring complex real-time adjustments.
Solution Approach 2:
The patent modifies the polymer emulsion by introducing crosslinking agents and controlling the acid value parameter to enhance the steric network structure. This parameter change improves the polymer's ability to maintain dispersion stability under extreme conditions while keeping the manufacturing process relatively simple through standard crosslinking techniques.
3Manufacturing precision
If pigment is dispersed without sufficient electrostatic repulsion, then the ink composition is simpler, but flocculation occurs rapidly leading to non-uniform ink film and poor optical density
Solution Approach 1:
The patent changes the acid value parameter of the carboxylic acid monomer to 200-400 mg KOH/g, which significantly enhances electrostatic repulsion. This parameter change prevents pigment flocculation and ensures uniform ink film formation, achieving high manufacturing precision without requiring excessive polymer quantities.
Solution Approach 2:
The patent employs a composite polymer system where carboxylic acid monomer units provide electrostatic repulsion and hydrophobic monomer units provide steric network structure. This composite approach achieves uniform ink film and prevents flocculation through dual mechanisms, maintaining simple ink composition while ensuring manufacturing precision.
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 solution results in excellent ejection stability, fastness, and optical density of printed characters or images, maintaining good performance even after ink ejection interruption and under severe drying conditions.
Implementation Method 1
a water-based ink that contains at least pigment-containing water-insoluble crosslinked polymer particles (A), a polymer emulsion (B) and water, in which a water-insoluble crosslinked polymer constituting the crosslinked polymer particles (A) is obtained by subjecting a polymer that contains a constitutional unit derived from a carboxylic acid monomer having an acid value of not less than 200 mgKOH/g
Implementation Method 2
a water-insoluble crosslinked polymer constituting the crosslinked polymer particles (A) is obtained by subjecting a polymer that contains a constitutional unit derived from a carboxylic acid monomer having an acid value of not less than 200 mgKOH/g and a constitutional unit derived from a hydrophobic monomer, to crosslinking reaction with an epoxy compound
Data Source
AI summary
The present invention relates to a water-based ink containing at least pigment-containing water-insoluble crosslinked polymer particles (A), a polymer emulsion (B) and water, in which a water-insoluble crosslinked polymer constituting the crosslinked polymer particles (A) is obtained by subjecting a polymer that contains a constitutional unit derived from a carboxylic acid monomer having an acid value of not less than 200 mgKOH/g and a constitutional unit derived from a hydrophobic monomer, to crosslinking reaction with an epoxy compound, and a polymer constituting the polymer emulsion (B) contains a constitutional unit derived from a carboxylic acid monomer and a constitutional unit derived from a hydrophobic monomer. The water-based ink of the present invention is excellent in ejection stability and fastness of the printed characters or images while maintaining good optical density.