Lithographic Printing Plate Precursor With Stable IR Printout Contrast
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Solution Overview
Problem
Existing infrared-sensitive lithographic printing plate precursors face challenges in achieving strong printout contrast between exposed and unexposed regions, which is not detectable by electronic reading devices due to mismatched absorption and emission peaks, and suffer from fading of printout images.
Innovation Solution
A lithographic printing plate precursor comprising a substrate with an infrared radiation-sensitive image-recording layer containing a free radical initiator, a free radically polymerizable composition, an acid-sensitive color-changing compound, and a color-changing compound, which forms a colored compound with strong absorption in the 600-700 nm range, enhancing printout visibility for both human eyes and electronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acid-sensitive color precursors such as lactone based leuco dyes are used in infrared radiation-sensitive imaging compositions, then the imaging sensitivity is improved, but the printout contrast becomes insufficient and fades after imaging
Solution Approach 1:
The patent changes the chemical parameters of the color-forming composition by using sulfonate esters instead of traditional lactone-based leuco dyes. This parameter change results in a color-forming compound that provides both high imaging sensitivity and stable, non-fading printout contrast, resolving the contradiction between imaging sensitivity and printout stability.
2Reliability
If more sensitive color forming compositions are used to strengthen printout, then the printout contrast is improved, but the white light sensitivity increases causing background color formation in non-imaged areas
Solution Approach 1:
The patent applies local quality by designing a color-forming composition with specific chemical properties (sulfonate esters) that selectively responds to infrared radiation while being insensitive to white light. This localized chemical property ensures that color formation occurs only in imaged areas, providing strong printout contrast without background formation in non-imaged areas.
3Ease of manufacture
If traditional acid generation systems are used in on-press developable precursors, then the on-press development is achieved, but the acid generation efficiency is limited and printout is not strong
Solution Approach 1:
The patent uses a composite material approach by combining sulfonate ester compounds with appropriate initiators and monomers to create an imaging composition that provides both efficient on-press development and strong, stable printout. The composite system achieves superior acid generation efficiency while maintaining on-press developability.
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 precursor achieves a reflective absorbance difference of at least 0.02 between exposed and non-exposed regions, ensuring clear printout visibility with both human eyes and electronic sensors, and maintains stable printout images.
Implementation Method 1
a free radical initiator composition that is capable of generating free radicals upon exposure to infrared radiation
Implementation Method 2
an acid-sensitive color-changing compound that is represented by the following Formula (I)
Data Source
AI summary
IR-sensitive lithographic printing plate precursors provide a stable print-out image using a unique IR radiation-sensitive composition in an infrared radiation-sensitive image-recording layer. This IR radiation-sensitive composition includes: (1) a free radical initiator composition comprising a borate compound; (2) a free radically polymerizable composition; (3) an acid-sensitive color-changing compound that is represented by the Formula (I) identified herein; (4) an infrared absorber material; and a (5) color-changing compound of Formula (III) or Formula (IV) identified herein. After IR imaging, the exposed precursors exhibit desirable printout images especially in the 600-700 nm region of the electromagnetic spectrum and especially for observation using electronic sensing devices. The imaged precursors can be developed off-press or on-press.