Core-Shell Polymer Particle Ink Jet Ink Surfactant-Free Stability
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Solution Overview
Problem
Ink jet inks containing polymer particles synthesized by emulsion polymerization suffer from low ejection stability due to residual surfactants, and the use of surfactants with high defoaming properties compromises water resistance of images.
Innovation Solution
Development of an ink jet ink with a polymer particle having a core-shell structure, where the shell portion contains a copolymer with specific units derived from compounds like R1—(C2H4O)n—R2 and an α,β-unsaturated hydrophobic compound, and the core portion contains an α,β-unsaturated hydrophobic compound, eliminating the need for surfactants and enhancing both ejection stability and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a surfactant is used in emulsion polymerization to stabilize monomer dispersion, then polymer particle formation is improved, but residual surfactant in the ink lowers defoaming properties and increases viscosity
Solution Approach 1:
The patent removes the surfactant component from the emulsion polymerization system entirely. Instead of using conventional surfactants to stabilize monomer dispersion, the invention employs a surfactant-free emulsion polymerization method that still produces stable polymer particles through alternative mechanisms, thereby eliminating residual surfactant in the final ink composition
Solution Approach 2:
The patent introduces a novel intermediary substance or mechanism that facilitates monomer dispersion and polymerization without requiring conventional surfactants. This intermediary enables stable emulsion formation through non-surfactant means, allowing polymer particle synthesis while avoiding the harmful residual surfactant problem
2Stability of the object's composition
If a polymer particle with ionic hydrophilic group is used to improve dispersion, then fastness properties are enhanced, but water resistance of the image is lowered
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell portion contains ionic hydrophilic groups for dispersion stability while the core portion provides water resistance. This spatial differentiation of functional groups allows simultaneous achievement of good dispersion and water resistance, as each region performs its specific function without compromising the other
3Object-generated harmful factors
If a polymer particle with high defoaming properties is used, then bubble disappearance is improved, but ejection stability of the ink is lowered
Solution Approach 1:
The patent removes the surfactant that causes ejection stability problems while maintaining defoaming properties through alternative means. By eliminating the surfactant component entirely and using surfactant-free emulsion polymerization, the ink achieves both good defoaming performance and stable ejection characteristics without the trade-off present in conventional formulations
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 jet ink achieves high ejection stability and water resistance by forming a polymer particle with a spherical core and branched shell structure, which balances hydrophilicity and hydrophobicity, preventing surfactant adhesion and improving image quality.
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—R2 where R1 is at least one selected from a vinyl group, an allyl group, an acryloyl group and a methacryloyl group, R2 is a hydrogen atom or an alkyl group, and n is 30 or more and 100 or less, and a unit derived from an α,β-unsaturated hydrophobic compound (a2)
Implementation Method 2
preventing surfactant adhesion and improving image quality
Data Source
AI summary
An ink jet ink containing a coloring material and a polymer particle, wherein the polymer particle has a core portion and a shell portion, 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—R2 where R1 is at least one selected from a vinyl group, an allyl group, an acryloyl group and a methacryloyl group, R2 is a hydrogen atom or an alkyl group, and n is 30-100, and a unit derived from an α,β-unsaturated hydrophobic compound (a2), a proportion of the unit derived from the compound (a1) to the copolymer A is 50-90% by mass or less, a proportion of the unit derived from the compound (a2) to the copolymer A is 10-50% by mass or less, and the core portion contains a polymer of an α,β-unsaturated hydrophobic compound (b).