Cross-Linked Ink-Jet Ink Composition for Nozzle Clogging Resistance
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Solution Overview
Problem
Existing ink-jet inks face issues with nozzle clogging due to pigment aggregation and sedimentation, and insufficient storage stability, particularly in water-based inks, which affect print quality and reliability.
Innovation Solution
An ink-jet ink composition featuring a cross-linked dispersion resin made from specific monomers and an epoxy group-containing cross-linking agent, combined with a solvent having a controlled n-octanol/water partition coefficient, to enhance dispersion stability and reduce viscosity, thereby minimizing nozzle clogging and improving storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pigment is dispersed in a dispersion resin to increase dispersion stability, then nozzle clogging is reduced, but the ink composition becomes more complex
Solution Approach 1:
The patent uses a composite dispersion resin system comprising multiple functional components: a carboxyl group-containing polymer (5-50 mass%), a hydroxyl group-containing polymer (5-50 mass%), and a sulfonic acid group-containing polymer (1-20 mass%). This composite approach combines the benefits of different polymer types to achieve superior pigment dispersion and nozzle clogging resistance while maintaining manageable composition complexity through defined ratios.
Solution Approach 2:
The patent optimizes specific parameters of the dispersion resin system, including the weight ratios of different polymer components, the carboxyl value (50-300 mg KOH/g), hydroxyl value (20-200 mg KOH/g), and sulfonic acid group content (1-20 mass%). By controlling these parameters within specific ranges, the invention achieves enhanced dispersion stability and reduced nozzle clogging without excessive complexity.
2Stability of the object's composition
If water-based ink is used to achieve high storage stability, then pigment dispersion is maintained, but viscosity becomes too high causing nozzle clogging
Solution Approach 1:
The patent adjusts the viscosity parameter by controlling the composition and molecular weight of the dispersion resin system. The carboxyl value, hydroxyl value, and sulfonic acid group content are optimized to achieve the right balance between storage stability and flowability. The resin molecular weight is also controlled (500-10,000 g/mol) to prevent excessive viscosity while maintaining pigment dispersion.
Solution Approach 2:
The patent creates a composite resin system where the sulfonic acid group-containing polymer acts as a viscosity modifier and flow aid, while the carboxyl and hydroxyl group-containing polymers provide dispersion stability. This composite approach allows the ink to maintain high storage stability without excessive viscosity that would cause nozzle clogging.
3Reliability
If the dispersion resin has high dispersion stability to prevent pigment aggregation, then nozzle clogging is reduced, but the ink formulation becomes more complex
Solution Approach 1:
The patent employs a composite resin formulation with three specific polymer components working synergistically: carboxyl group-containing polymer for pigment binding, hydroxyl group-containing polymer for dispersion stability, and sulfonic acid group-containing polymer for electrostatic repulsion and flow control. This structured composite approach achieves high dispersion stability while keeping the formulation manageable through defined compositional ranges.
Solution Approach 2:
The patent assigns specific functional qualities to different parts of the resin system: the carboxyl group-containing polymer provides local pigment binding and stabilization, the hydroxyl group-containing polymer provides local dispersion maintenance, and the sulfonic acid group-containing polymer provides local electrostatic repulsion. This division of functional qualities achieves high overall dispersion stability without requiring excessive complexity in the overall formulation.
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 ink achieves reduced nozzle clogging and enhanced storage stability, ensuring consistent print quality and reliability by maintaining pigment dispersion and controlling ink viscosity within optimal ranges.
Implementation Method 1
a cross-linked product made of: a neutralized product of a specific resin... and an epoxy group-containing cross-linking agent
Implementation Method 2
The specific organic solvent has an n-octanol/water partition coefficient of not less than 0 and less than 0.55
Data Source
AI summary
An ink-jet ink contains an aqueous vehicle, pigment particles containing a pigment and a dispersion resin, and a specific organic solvent. The dispersion resin is a cross-linked product made of: a neutralized product of a specific resin obtained by copolymerizing, in 100 parts by mass of a predetermined solvent, 1 to 65 parts by mass of α-methylstyrene monomer, 1 to 50 parts by mass of styrene monomer, 10 to 40 parts by mass of (meth)acrylic acid monomer, and 1 to 10 parts by mass of non-ionic monomer; and an epoxy group-containing cross-linking agent. The specific resin has an acid value of 50 to 300 mgKOH/g, a weight average molecular weight of 3000 to 18000, and a percentage of neutralization of 20% to 100%. The specific organic solvent has a LogP of 0 to 0.55 exclusive and a content of the specific organic solvent is 25.0% to 35.0% by mass.