Silver Nanoparticle Gel Ink for UV-Stable Fixed Color
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Solution Overview
Problem
Existing aqueous gel inks rely on dyes and pigments that are expensive, irritating to biological membranes, and pose allergy risks, while lacking UV resistance and stability.
Innovation Solution
A process to create an aqueous gel ink using silver nanoparticles, prepared through a low-temperature, eco-friendly method involving silver salts, alkali metal citrate, alkali metal hydride, ascorbic acid, and hydrogen peroxide, which are mixed with a gel-based matrix to achieve a stable, fixed color ink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If dyes and pigments are used in aqueous gel inks, then color is achieved, but production costs increase and biological irritation occurs
Solution Approach 1:
The invention changes the fundamental parameter of color generation from molecular dyes/pigments to metallic silver nanoparticles. This parameter change eliminates biological irritation while maintaining color functionality, and the nanoparticles can be produced cost-effectively through chemical reduction methods using common reagents like citrate and borohydride
Solution Approach 2:
The invention replaces expensive, sensitive organic dyes and pigments with inexpensive inorganic silver nanoparticles that can be synthesized from cheap precursors. The nanoparticles serve as a durable, non-irritating alternative that maintains color stability without the high costs associated with traditional coloring agents
2Reliability
If dyes and pigments are used in aqueous gel inks, then color is achieved, but UV resistance and light stability are insufficient
Solution Approach 1:
The invention fundamentally changes the color-generating material from organic dyes/pigments to inorganic silver nanoparticles. This parameter change confers superior UV resistance and light stability because metallic nanoparticles are inherently more resistant to photodegradation than organic molecules, eliminating color fading issues
Solution Approach 2:
The invention creates a composite system where silver nanoparticles are dispersed within the gel matrix, combining the optical properties of metallic nanoparticles with the stabilizing environment of the gel medium. This composite structure enhances both UV resistance and color stability
3Reliability
If antibacterial agents are added to aqueous gel inks, then bacterial growth is controlled, but the formulation becomes more complex and potentially more irritating
Solution Approach 1:
The invention makes the silver nanoparticles serve multiple functions simultaneously: they provide color through plasmonic effects and provide antibacterial protection through silver's inherent biocidal properties. This multi-functionality eliminates the need for separate antibacterial additives, simplifying the formulation while reducing biological irritation
Solution Approach 2:
The invention merges the coloring function and antibacterial function into a single component (silver nanoparticles). By combining these two functions that were previously provided by separate additives, the formulation becomes simpler and less irritating while maintaining both color and bacterial control
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 is cost-effective, non-irritating, UV-resistant, and maintains color stability over time, offering antibacterial properties and ecological benefits.
Implementation Method 1
preparing an aqueous suspension of silver nanoparticles with fixed color by mixing silver salts with: water, a mixture of at least an alkali metal or alkaline earth metal salt of citrate, preferably an alkali citrate salt and an alkali metal hydride, preferably NaBH4, a further reducing agent, preferably ascorbic acid
Implementation Method 2
The inventors have surprisingly found that the new aqueous inks containing nanoparticles-based are also resistant to UV light thereby improving light stability over time
Implementation Method 3
Moreover silver nanoparticles have antibacterial properties and therefore the amount of other antibacterial agents can be lowered
Data Source
AI summary
The present invention concerns a process for preparing an aqueous gel ink with fixed color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink; (ii) preparing an aqueous suspension of silver nanoparticles with fixed color by mixing silver salts with: —water, —a mixture of at least an alkali metal or alkaline earth metal salt of citrate, preferably an alkali citrate salt and an alkali metal hydride, preferably NaBH4, —a further reducing agent, preferably ascorbic acid, —and oxidizing agent, preferably hydrogen peroxide H2O2 (iii) adding under agitation the aqueous suspension of silver nanoparticles obtained in step (ii) to the gel-based matrix of aqueous ink obtained in step (i), to obtain an aqueous gel ink with fixed color with silver nanoparticles dispersed therein.