Cross-Linked Quinacridone Ink Composition for Nozzle Clog Reduction
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Solution Overview
Problem
Existing ink-jet inks containing quinacridone-based pigments face issues with nozzle clogging and insufficient storage stability, particularly due to high ion concentrations and poor dispersion stability of pigment particles.
Innovation Solution
The ink formulation includes a cross-linked resin made from a specific copolymer with optimized repeating unit contents, acid value, molecular weight, and neutralization percentage, combined with a polyfunctional epoxy cross-linking agent, and controlled alkali metal ion concentration to enhance dispersion stability and reduce nozzle clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the total concentration of alkali metal ions is reduced to not more than 500 ppm, then storage stability is improved, but the cross-linked resin formulation becomes more complex
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration of alkali metal ions (reducing to not more than 500 ppm) and optimizing the composition parameters of the copolymer (repeating unit contents, acid value, molecular weight) and cross-linking agent to achieve both low ion concentration and stable cross-linked resin structure
Solution Approach 2:
The patent uses composite materials by combining a specifically formulated copolymer with controlled repeating units (α-methylstyrene, styrene, (meth)acrylic acid, and alkylene glycol (meth)acrylate) and cross-linking agents (polyfunctional epoxy compounds with hydroxy groups) to create a cross-linked resin system that maintains stability while reducing ion concentration
2Stability of the object's composition
If the cross-linked resin is optimized with specific copolymer composition and cross-linking rate, then dispersion stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by specifying precise ranges for copolymer composition (first repeating unit: 1-65%, second: 1-60%, third: 10-40%, fourth: 1-12%), acid value (50-300 mgKOH/g), molecular weight (3000-18000), and cross-linking rate (25-90%) to optimize dispersion stability
Solution Approach 2:
The patent applies local quality by assigning specific functional roles to different repeating units in the copolymer: α-methylstyrene units provide hydrophobicity for pigment dispersion, styrene units contribute to resin structure, (meth)acrylic acid units provide carboxyl groups for cross-linking, and alkylene glycol (meth)acrylate units provide hydrophilicity and compatibility with aqueous vehicle
3Stability of the object's composition
If the cross-linking rate is increased to not less than 25%, then pigment particle stability is improved, but resin aggregation may increase
Solution Approach 1:
The patent applies parameter changes by optimizing the cross-linking rate to a specific range (not less than 25% and not more than 90%) and controlling the acid value (50-300 mgKOH/g) and molecular weight (3000-18000) of the copolymer to achieve sufficient pigment particle stabilization while preventing excessive resin aggregation
Solution Approach 2:
The patent uses the cross-linked resin as an intermediary substance that bridges pigment particles and the aqueous vehicle, providing steric stabilization and preventing direct pigment-pigment aggregation while maintaining compatibility with the ink 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 optimized ink-jet ink achieves reduced nozzle clogging and improved storage stability by ensuring excellent dispersion stability of pigment particles, maintaining ink quality over time.
Implementation Method 1
The cross-linked resin is a cross-linked product made of a specific resin and a specific cross-linking agent
Implementation Method 2
The specific cross-linking agent contains a polyfunctional epoxy compound having, in a molecule thereof, two or more epoxy groups and one or more hydroxy groups
Data Source
AI summary
In an ink-jet ink, a pigment is a quinacridone-based pigment. A specific resin is a neutralized product of a specific copolymer containing α-methylstyrene-derived units, styrene-derived units, (meth)acrylic acid-derived units, and (di)alkylene glycol (meth)acrylate-derived units in respective predetermined amounts, wherein an acid value of the specific copolymer is not less than 50 mgKOH/g and not more than 300 mgKOH/g, and a number average molecular weight (Mn) of the specific copolymer is not less than 3000 and not more than 18000. The specific resin has a percentage of neutralization of not less than 20% and not more than 100%. A specific cross-linking agent contains a polyfunctional epoxy compound and has a water solubility of not less than 80%. A cross-linked resin has a cross-linking rate of not less than 25% and not more than 90%. A concentration of alkali metal ions in an aqueous vehicle is not more than 500 ppm.