Aqueous Ink Silver Particles Gloss Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aqueous inks containing silver particles used for recording metallic images suffer from poor initial glossiness and degradation over time due to the formation of silver chloride crystals when used with recording media containing chloride ions.
Innovation Solution
An aqueous ink formulation incorporating a first reducing agent with an oxidation-reduction potential less than zero and a second reducing agent with an oxidation-reduction potential greater than or equal to zero, specifically tertiary amines or polyhydric alcohols, to reduce silver chloride and prevent its oxidation, thereby maintaining image glossiness both initially and after storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If silver particles are used as coloring material in aqueous ink, then metallic image with favorable glossiness can be recorded, but original glossiness degrades gradually when the recorded image is stored
Solution Approach 1:
The patent applies preliminary action by incorporating reducing agents (first reducing agent with E° < 0 V and second reducing agent with E° ≥ 0 V) into the ink formulation before recording. These reducing agents proactively reduce silver chloride to silver particles during the recording process and continue to prevent re-oxidation during storage, thereby maintaining glossiness both initially and after storage. The reducing agents are present in advance to counteract the harmful oxidation reaction before it can degrade the image quality.
2Ease of manufacture
If aluminum pigment is used to record metallic image, then recording process is simple, but glossiness of recorded image is poor
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the ink formulation. Instead of using aluminum pigment, the patent changes the metal particle parameter to silver particles and adjusts the redox potential parameters by incorporating specific reducing agents with defined oxidation-reduction potentials. This parameter change transforms the ink from one that produces poor glossiness to one that achieves excellent metallic glossiness while maintaining ease of recording.
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 achieves excellent glossiness both immediately after recording and after storage by efficiently reducing silver chloride, preventing its growth and maintaining image quality.
Implementation Method 1
a first reducing agent and a second reducing agent, wherein the first reducing agent is a compound that has an oxidation-reduction potential R1 (mV) satisfying R1 < 0
Implementation Method 2
the first reducing agent is a compound that has an oxidation-reduction potential R1 (mV) satisfying R1 < 0 and that is at least one selected from a group consisting of tertiary amines and polyhydric alcohols
Data Source
AI summary
An aqueous ink containing silver particles, a first reducing agent and a second reducing agent, wherein the first reducing agent is a compound that has an oxidation-reduction potential R1 (mV) satisfying R1<0, and the second reducing agent is a compound that has an oxidation-reduction potential R2 (mV) satisfying R2≥0 and that is at least one selected from a group consisting of tertiary amines and polyhydric alcohols in which a plurality of hydroxy groups are included in one of two structures divided according to a position between any one of two adjacent carbon atoms of the longest carbon chain in the molecule.