Silver Nanoparticle Inkjet Ink for Glossy Metallic Printing
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Solution Overview
Problem
Thermal inkjet printing faces challenges in producing metallic images with high glossiness due to nozzle clogging and settling of large metallic pigments, requiring mechanical mechanisms for suspension and inefficient drying processes.
Innovation Solution
Inkjet inks containing silver nanoparticles, trimethylene glycol, and 1,2-hexanediol provide stable suspension and rapid coalescence to form high-gloss metallic films without mechanical aids, maintaining decap stability and efficient drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If large metallic pigments are used to achieve high metallic luster, then the metallic image quality is improved, but nozzle clogging and settling occur
Solution Approach 1:
The large metallic pigment particles are segmented into smaller nanoparticles (average particle size less than 100 nm, preferably less than 50 nm). This segmentation allows the metallic particles to remain suspended without settling while still providing adequate metallic luster when deposited in sufficient quantity
Solution Approach 2:
The particle size parameter of the metallic pigment is changed from large (100 nm or larger) to small (less than 100 nm, preferably less than 50 nm). This parameter change resolves the contradiction by enabling both suspension stability and metallic luster achievement
2Stability of the object's composition
If dispersants are increased to maintain pigment suspension, then running stability is improved, but metallic luster deteriorates
Solution Approach 1:
The dispersant concentration parameter is optimized to a specific range (0.1-10 wt%, preferably 0.5-5 wt%) rather than using high concentrations. This optimized parameter range provides sufficient suspension stability while minimizing the negative impact on metallic luster
Solution Approach 2:
The function of dispersants is copied by the combination of small nanoparticle size and specific solvent system (containing glycols and water), which together provide suspension stability without requiring high dispersant loadings that would dull the metallic finish
3Reliability
If high boiling solvent components are used to prevent nozzle drying during decap, then decap stability is improved, but drying time increases
Solution Approach 1:
The solvent system is segmented into multiple components with different volatility characteristics rather than using a single high-boiling solvent. This includes water (high volatility), glycols (moderate volatility), and optional high-boiling components (low volatility), allowing balanced performance
Solution Approach 2:
A composite solvent system is used comprising water, glycols (such as ethylene glycol, propylene glycol, butylene glycol), and optionally high-boiling components. This composite system balances decap stability and drying time by combining components with different evaporation rates
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 inkjet inks ensure reliable jetting, prolonged decap times, and quick drying, producing high-gloss metallic images on various substrates without nozzle clogging or settling issues.
Implementation Method 1
a resistor is heated rapidly to produce a vapor bubble
Implementation Method 2
produce ink droplets from thermal vaporization of an ink solvent
Implementation Method 3
drying of the inkjet ink and coalescence of the silver nanoparticles provides high gloss metallic prints
Data Source
AI summary
An inkjet ink that includes (A) metal nanoparticles (e.g., silver nanoparticles); (B) trimethylene glycol; and (C) 1,2-hexanediol; the inkjet ink being characterized by extended decap times, long running stability, quick drying properties, and the ability to form metallic printed images with high metallic luster (high gloss). Also provided are a printed article which includes a metallic film formed from the inkjet ink disposed on a substrate, and a method of forming a metallic printed image, whereby the inkjet ink is applied via a thermal inkjet printhead and is subsequently dried, such as with a near infrared heater.