Fluorescent Pigment Stabilization via Amide Bonding
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Solution Overview
Problem
Fluorescent dyes used in toners for security printing are prone to thermal degradation and pH instability, while hard fluorescent pigments offer chemical and light stability but restrict dye mobility and require high fusing temperatures, making them unsuitable for certain applications.
Innovation Solution
Fluorescent particles are stabilized by chemically attaching waxy aliphatic chains to fluorescent pigments, creating softer, resin-like characteristics and allowing for oil-less fusing, which simplifies the design and maintains fluorescent properties for security printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fluorescent dyes are used in toners, then homogeneous printing compositions are achieved, but thermal degradation occurs and fluorescence is lost after continuous heating
Solution Approach 1:
The patent combines fluorescent dyes with polymer matrices to create composite fluorescent particles. The dye is incorporated into the polymer matrix, which provides thermal stability while maintaining the fluorescent properties. This composite structure prevents thermal degradation of the dye during toner preparation and fusing processes.
Solution Approach 2:
The polymer matrix acts as an intermediary between the fluorescent dye and the harsh environment of high temperature processing. It protects the dye from direct thermal exposure and chemical degradation, allowing the dye to maintain its fluorescent properties throughout the toner manufacturing and printing process.
2Stability of the object's composition
If hard fluorescent pigments are used, then chemical and light stability are improved, but dye mobility is restricted and high fusing temperatures are required
Solution Approach 1:
The patent creates composite fluorescent particles consisting of fluorescent dyes embedded in polymer matrices. This composite structure provides chemical stability like hard pigments while maintaining the softer, more fusible characteristics needed for lower temperature processing.
Solution Approach 2:
The patent changes the physical state and softness of the fluorescent particles by using polymer matrices with appropriate glass transition temperatures. This allows the particles to be soft enough for low-temperature fusing while maintaining chemical stability during storage and handling.
3Reliability
If hard polymer matrix is used to protect dye, then chemical degradation is prevented, but mobility of dye is restricted and undesired effects on fusing occur
Solution Approach 1:
The patent optimizes the glass transition temperature and molecular weight of the polymer matrix to achieve the right balance between protection and processability. The matrix is designed to be stable during storage but becomes sufficiently mobile at fusing temperatures to allow proper toner fusion without requiring excessive heat.
Solution Approach 2:
The patent creates local variations in the polymer matrix structure, with regions of higher stability for chemical protection and regions of controlled mobility for fusing. The matrix composition can be tailored to provide different properties at different stages of the printing process.
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 stabilized fluorescent particles provide improved thermal and chemical stability, reduced crystallinity, and compatibility with toner binders, enabling better image quality and lower toner coverage without the need for high fusing temperatures.
Implementation Method 1
Under ultraviolet illumination, however, the fluorescent features of the document are revealed in the form of a bright emission by the fluorescent dyes in the visible spectrum.
Implementation Method 2
Fluorescent particles are stabilized by chemically attaching waxy aliphatic chains to fluorescent pigments
Data Source
AI summary
A fluorescent particle includes a fluorescent pigment, such as a trans-dicarboxylic-indenofluorenone, and at least one stabilizing wax chemically attached to the fluorescent pigment. The stabilizing wax includes an amine group at its terminal end and the fluorescent pigment includes at least one carboxylic acid group, where the amine group reacts with the carboxylic acid group to form an amide bond. A method for making fluorescent particles for use in toners by chemically attaching at least one stabilizing wax to a fluorescent pigment where the at least one stabilizing wax includes an amine group at its terminal end and the fluorescent pigment includes at least one carboxylic acid group. A toner may include a resin and the fluorescent particle.