Recording Liquid Shear Thinning for Stable Silver Glitter
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Solution Overview
Problem
Existing recording liquids with small mean number diameter luster pigments struggle to produce printed matter with a high level of glitter and color hue close to silver, while maintaining discharging stability in inkjet methods, due to waviness cycles that optically exhibit structural colors other than silver.
Innovation Solution
A recording liquid containing a luster pigment with a mean number diameter of less than 200 nm, combined with a modified ethylene vinyl acetate polymer or a polyamide amine salt and aliphatic acid amide, which adjusts viscosity to 40 mPa·s or less at 20 degrees C, and includes resin particles and a silicone-based surfactant to enhance glitter and color hue stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a luster pigment with small mean number diameter is used, then the glitter level and color hue close to silver are improved, but the discharging stability deteriorates due to waviness cycles exhibiting structural colors
Solution Approach 1:
The patent applies parameter changes by optimizing the mean number diameter of the luster pigment to less than 200 nm and controlling the viscosity of the recording liquid to 40 mPa·s or less at 20°C. These parameter adjustments enable small pigment particles to be discharged stably without forming waviness cycles, resolving the contradiction between achieving high glitter and maintaining discharging stability
Solution Approach 2:
The patent introduces shear-thinning agents (modified ethylene vinyl acetate polymer or polyamide amine salt with aliphatic acid amide) that provide dynamic viscosity adjustment. The viscosity decreases under shear stress during inkjet discharge, enabling stable discharge of fine pigment particles, then recovers to maintain formulation stability during storage
2Reliability
If the viscosity is reduced to improve discharging stability, then the discharging stability is improved, but the luster and abrasion resistance deteriorate
Solution Approach 1:
The patent uses composite materials by combining shear-thinning agents (modified ethylene vinyl acetate polymer or polyamide amine salt with aliphatic acid amide) with luster pigment and resin particles. This composite formulation achieves low viscosity (≤40 mPa·s) for stable discharge while the resin particles and pigment aggregation provide sufficient luster and abrasion resistance
Solution Approach 2:
The shear-thinning agent acts as an intermediary substance that mediates between viscosity requirements. It enables the recording liquid to have low viscosity during discharge (improving stability) while maintaining adequate viscosity during storage (preserving luster and abrasion resistance through proper pigment suspension
3Illumination intensity
If resin particles and surfactant are added to enhance glitter and color stability, then the glitter and color hue stability are improved, but the formulation complexity increases
Solution Approach 1:
The patent applies multi-functionality by selecting resin particles and silicone-based surfactant that serve multiple functions simultaneously. The resin particles provide both structural support for luster and aid in pigment dispersion, while the surfactant enhances both glitter appearance and discharge stability, reducing the need for additional separate additives
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 solution achieves highly glossy printed matter with a color hue close to silver, improved discharging stability, and balanced luster and abrasion resistance, by optimizing pigment size, polymer composition, and surfactant use.
Implementation Method 1
a modified ethylene vinyl acetate polymer or the combination of a polyamide amine salt and an aliphatic acid amide, wherein the recording liquid has a viscosity of 40 mPa·s or less at 20 degrees C
Implementation Method 2
a luster pigment having a mean number diameter of less than 200 nm
Implementation Method 3
Printed matter having a metallic luster image including a silver coloring material, which particularly has a mirror surface with excellent image clarity
Data Source
AI summary
A recording liquid contains a luster pigment having a mean number diameter of less than 200 nm and a modified ethylene vinyl acetate polymer or the combination of a polyamide amine salt and an aliphatic acid amide, wherein the recording liquid has a viscosity of 40 mPa·s or less at 20 degrees C.