Fluorescent Pigment Dispersion for Invisible Security Marking
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Solution Overview
Problem
Current security technologies for products are insufficient in providing high security and light fastness, especially for items that need to be stored for long periods, as they lack effective means to embed invisible information that is not recognizable under visible light.
Innovation Solution
A pigment dispersion and toner system that includes a fluorescent agent excited by UV light, with specific emission intensity ratios and binder resin formulations, allowing for high security and light fastness by controlling emission spectra and particle sizes to enhance visibility and invisibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fluorescent agent is blended into paint or ink to form an invisible image, then security is improved, but light fastness deteriorates
Solution Approach 1:
The patent changes the excitation wavelength parameter of the fluorescent agent to 400 nm or less (UV range), which fundamentally alters how the fluorescent material interacts with light. This parameter change enables the fluorescent agent to remain invisible under visible light while maintaining stability and light fastness under various lighting conditions including sunlight exposure.
Solution Approach 2:
The patent creates a composite fluorescent material system consisting of a fluorescent agent combined with a binder resin. This composite structure protects the fluorescent agent molecules, improving their light fastness and durability while maintaining their security function. The binder resin acts as a protective matrix that stabilizes the fluorescent properties over time.
2Illumination intensity
If fluorescent agent content is increased to improve visibility under UV light, then security detection is improved, but granularity increases
Solution Approach 1:
The patent applies local quality by using a binder resin that specifically binds to and disperses the fluorescent agent uniformly throughout the composition. This localized binding action ensures that fluorescent agent molecules are evenly distributed at the molecular level rather than clustering, maintaining smooth texture while achieving high emission intensity through uniform concentration distribution.
Solution Approach 2:
The patent optimizes the concentration ratio parameter of the fluorescent agent within specific ranges (0.1-10 mass% relative to binder resin) to achieve the optimal balance between emission intensity and granularity. This parameter optimization ensures sufficient UV response while preventing visible granularity in the applied coating.
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 system provides high security through visible emission under UV light and maintains light fastness, improving visibility and reducing granularity, while ensuring the image remains invisible under visible light, thus enhancing security and durability.
Implementation Method 1
a fluorescent agent that is excited with light at a wavelength of 400 nm or less and that has an emission spectrum for excitation light at a wavelength of 250 nm or more and 290 nm or less in a visible light range
Data Source
AI summary
The pigment dispersion is a pigment dispersion including a fluorescent agent, wherein, when at a wavelength of 250 nm or more and 290 nm or less, an integral value of an emission intensity in a wavelength range of 400 nm or more and 700 nm or less of an emission spectrum of the fluorescent agent for excitation light is represented by F1, an integral value of an emission intensity in a wavelength range of 400 nm or more and 700 nm or less of an emission spectrum of the pigment dispersion for excitation light is represented by F2, and a ratio of the fluorescent agent contained in a solid content obtained when the pigment dispersion is heated at 130° C. until a change in mass of the pigment dispersion reaches 0.3%/min or less is represented by W1 (mass%), the F1, the F2, and the W1 satisfy the formulae F2x 100/W1≥F1 ×0.30 and 5.0≤W1≤80.0.