Core-Shell Polymer Particle Ink for Ejection Stability and Water Resistance
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Solution Overview
Problem
The existing two-liquid reaction system for image recording suffers from low ejection stability, blurring, and poor water resistance due to the use of polymer particles with high softness and ionic groups, which affect the ink's dispersion stability and reactivity with reaction agents.
Innovation Solution
The development of a polymer particle with a core-shell structure, where the shell portion contains a copolymer A with specific units derived from compounds like polyethylene glycol and α,β-unsaturated hydrophobic compounds, and the core portion is made of α,β-unsaturated hydrophobic compounds, enhancing dispersion stability and reactivity while improving ejection stability and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer particle with ionic groups is used in the two-liquid reaction system, then the reactivity with reaction agent is improved, but the ejection stability of the ink deteriorates
Solution Approach 1:
The polymer particle is divided into a core portion and a shell portion. The core portion contains the ionic functional groups for high reactivity with the reaction agent, while the shell portion consists of a copolymer with hydrophobic and hydrophilic segments that provide ejection stability. This segmentation allows each part to perform its specific function without interfering with the other.
Solution Approach 2:
Different regions of the polymer particle are assigned different properties: the core portion has high ionic character for reactivity, while the shell portion has a balanced composition of hydrophobic and hydrophilic segments for ejection stability. The shell portion's local quality of having both hydrophobic and hydrophilic characteristics enables the ink to maintain stability during ejection while the core provides the necessary chemical reactivity.
2Stability of the object's composition
If a polymer particle with high softness is used, then the dispersion stability is improved, but the water resistance of the image deteriorates
Solution Approach 1:
The polymer particle structure is segmented into a core portion that provides water resistance and a shell portion that provides dispersion stability. The shell portion's copolymer structure with both hydrophobic and hydrophilic segments enables stable dispersion, while the core portion's hydrophobic character ensures water resistance of the recorded image.
Solution Approach 2:
The polymer particle is a composite structure combining different polymer components with distinct properties. The core portion uses hydrophobic polymers for water resistance, while the shell portion uses a copolymer of hydrophobic and hydrophilic segments for dispersion stability. This composite approach allows simultaneous achievement of both required properties.
3Stability of the object's composition
If the shell portion contains only hydrophilic polymer, then the ejection stability is improved, but the water resistance and blurring suppression deteriorate
Solution Approach 1:
The shell portion is designed with local quality variations, containing both hydrophobic segments and hydrophilic segments in a copolymer structure. The hydrophilic segments contribute to ejection stability by improving ink flow, while the hydrophobic segments contribute to water resistance and blurring suppression. This local quality distribution within the shell portion enables simultaneous achievement of multiple performance requirements.
Solution Approach 2:
The shell portion is constructed as a composite copolymer material combining hydrophobic and hydrophilic polymer segments. This composite structure allows the shell to simultaneously provide ejection stability (through hydrophilic segments) and water resistance with blurring suppression (through hydrophobic segments), resolving the contradiction between these properties.
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
This approach significantly improves ejection stability, suppresses blurring, and enhances the water resistance of the resulting image, achieving a high level of performance in the two-liquid reaction system.
Implementation Method 1
the shell portion contains a copolymer A having a unit derived from a compound (a1) represented by a general formula (1) of R1—(C2H4O)n—C2H4OCO—R2—COOH where R1 is at least one selected from a vinyl group, an allyl group, an acryloyl group and a methacryloyl group, R2 is at least one selected from an alkylene group, a cycloalkylene group and a phenylene group, and n is 10 or more and 100 or less
Implementation Method 2
applying a liquid composition which destabilizes a dispersion state of the polymer particle in the ink to at least a part of a region of the recording medium where the ink is applied
Data Source
AI summary
An image recording method including applying an ink containing a coloring material and a polymer particle to a recording medium from a recording head of an ink jet system and applying a liquid composition which destabilizes a dispersed state of the polymer particle in the ink to at least a part of a region of the recording medium where the ink is applied, wherein the polymer particle in the ink has core and shell portions, the shell portion contains a copolymer A having a unit (50-90% mass) derived from a compound (a1) represented by a general formula (1) or (2) and a unit (10-50% mass) derived from an α,β-unsaturated hydrophobic compound (a2), and the core portion contains a polymer of an α,β-unsaturated hydrophobic compound (b).