Pigment Water Dispersion Crosslinked Polymer Stability
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Solution Overview
Problem
Current pigment water dispersions for ink-jet printing face challenges in achieving high continuous ejection stability, storage stability, and solvent resistance, particularly at high printing speeds, due to insufficient polymer adsorption onto pigment surfaces and inadequate solvent resistance.
Innovation Solution
A pigment water dispersion containing pigment-containing crosslinked polymer particles, where the crosslinked polymer is produced using a specific epoxy-based crosslinking agent, enhancing polymer adsorption and stability, and a process involving dispersion treatment and crosslinking to create a stable dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vinyl polymeric dispersant with crosslinkable moiety is used and crosslinked with a crosslinking agent, then storage stability is improved, but continuous ejection stability at high printing speeds deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the crosslinking agent from conventional epoxy types to a specific type with formula (1) containing a saturated aliphatic hydrocarbon group with 6-14 carbon atoms. This parameter change in the crosslinking agent's molecular structure resolves the contradiction by providing both storage stability through crosslinking and continuous ejection stability at high printing speeds, as the specific aliphatic hydrocarbon structure maintains appropriate polymer flexibility and adsorption characteristics.
2Reliability
If polymer crosslinking is performed to improve storage stability, then pigment dispersion stability is improved, but solvent resistance deteriorates
Solution Approach 1:
The patent modifies the chemical parameter of the crosslinking agent to a specific structure with formula (1) where R represents a saturated aliphatic hydrocarbon group with 6-14 carbon atoms. This structural parameter change enables the crosslinked polymer to achieve both storage stability and improved solvent resistance, as the aliphatic hydrocarbon chain length provides appropriate hydrophobicity and steric protection against solvent penetration while maintaining crosslinking efficacy.
3Reliability
If the amount of crosslinking agent is increased to improve storage stability, then pigment precipitation is prevented, but polymer adsorption onto pigment surface deteriorates
Solution Approach 1:
The patent changes the chemical parameter of the crosslinking agent to a specific structure with formula (1) containing a saturated aliphatic hydrocarbon group with 6-14 carbon atoms. This parameter change improves the agent's balance between hydrophobicity and reactivity, enabling effective polymer adsorption onto the pigment surface at lower concentrations while still achieving sufficient crosslinking for storage stability, thus resolving the contradiction between adsorption efficiency and storage stability.
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 resulting ink exhibits improved continuous ejection stability, storage stability, and solvent resistance, preventing precipitation and flocculation, and maintaining stability even in aqueous vehicles with high solvent content.
Implementation Method 1
a crosslinked polymer in the particles is a polymer that is crosslinked with a crosslinking agent represented by the following general formula (1)... wherein the crosslinked polymer is a crosslinked product of a water-dispersible polymer which is obtained by crosslinking the water-dispersible polymer with the crosslinking agent
Implementation Method 2
insufficient polymer adsorption onto pigment surfaces... enhancing polymer adsorption and stability
Data Source
AI summary
The present invention relates to [1] a pigment water dispersion containing pigment-containing crosslinked polymer particles, in which a crosslinked polymer in the particles is a polymer that is crosslinked with a crosslinking agent represented by the general formula (1), and [2] a process for producing a pigment water dispersion containing pigment-containing crosslinked polymer particles, including the following steps (1) and (2): Step (1): subjecting a pigment mixture containing a pigment, a water-dispersible polymer and water to dispersion treatment, thereby obtaining an aqueous pigment dispersion solution containing pigment-containing polymer particles; and Step (2): mixing the aqueous pigment dispersion solution obtained in the step (1) and a crosslinking agent represented by the general formula (1) to react the water-dispersible polymer with the crosslinking agent, thereby obtaining a pigment water dispersion containing pigment-containing crosslinked polymer particles.