Dispersion Resin Composition for Ink Re-Dispersibility and Heat Stability
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Solution Overview
Problem
Existing ink compositions using styrene-acrylic resins face issues with re-dispersibility after solidification and unsatisfactory dispersion stability, especially in high-temperature environments, leading to ejection failures.
Innovation Solution
A dispersion resin comprising a copolymer with constituent units of hydrophobic monomers, unsaturated aliphatic dicarboxylic acid monomers, and acrylamide monomers with sulfonic acid groups, having a weight-average molecular weight of 10,000 to 100,000, with specific content ratios, enhances re-dispersibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a usual dispersant such as styrene-acrylic resin is used, then the ink composition can be formulated, but the coloring material is hardly re-dispersed after solidification and dispersion stability is unsatisfactory in high temperature environments
Solution Approach 1:
The patent changes the chemical parameters of the dispersant by specifying a copolymer composition with three types of monomer units (hydrophobic monomer 40-90 mol%, unsaturated carboxylic acid monomer 5-50 mol%, and acrylamide monomer with sulfonic acid group 5-30 mol%). This specific compositional parameter change resolves the contradiction by providing both re-dispersibility and high-temperature stability that conventional styrene-acrylic resin cannot achieve
Solution Approach 2:
The patent creates a composite dispersant system by combining three different monomer units with complementary functions: hydrophobic units for adhesion to coloring material, carboxylic acid units for electrostatic stabilization, and sulfonic acid-containing acrylamide units for enhanced water solubility and re-dispersibility. This composite structure resolves the technical contradiction by integrating multiple functional mechanisms in one dispersant
2Productivity
If a usual dispersant is used, then the ink can be formulated, but ejection failures occur due to poor re-dispersibility
Solution Approach 1:
The patent modifies the molecular parameters of the dispersant by controlling the weight-average molecular weight (10,000-100,000) and the specific molar ratios of three functional monomer units. These parameter changes enable the dispersant to maintain effectiveness after solidification, ensuring reliable ejection without the failures associated with conventional dispersants
3Stability of the object's composition
If conventional dispersants are used, then formulation is simple, but dispersion stability deteriorates in high temperature storage conditions
Solution Approach 1:
The patent introduces temperature-resistant properties by changing the chemical composition parameters to include heat-stable functional groups (carboxylic acid and sulfonic acid groups) in specific proportions. This parameter optimization ensures the dispersant maintains its dispersing capability under high-temperature storage conditions where conventional dispersants fail
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 proposed resin improves re-dispersibility and maintains dispersion stability even in high-temperature conditions, ensuring reliable ink ejection and quality.
Implementation Method 1
the dispersion resin having a constituent unit A containing a hydrophobic monomer
Implementation Method 2
a constituent unit C containing an acrylamide monomer having a sulfonic acid group
Implementation Method 3
the dispersion resin having a constituent unit B containing an unsaturated aliphatic dicarboxylic acid monomer
Implementation Method 4
a constituent unit C containing an acrylamide monomer having a sulfonic acid group
Data Source
AI summary
A dispersion liquid includes water, a coloring material, and a dispersion resin that disperses the coloring material, and the dispersion resin has a constituent unit A containing a hydrophobic monomer, a constituent unit B containing an unsaturated aliphatic dicarboxylic acid monomer, and a constituent unit C containing an acrylamide monomer having a sulfonic acid group. The weight-average molecular weight of the dispersion resin is from 10,000 to 100,000, the content of the constituent unit A is 40 mol % or more relative to the total amount of the dispersion resin, and the content of the constituent unit B is 4 mol % or more relative to the total amount of the dispersion resin.