Infrared Absorbing Compound for Lithographic Printing Plate Ablation Control
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Solution Overview
Problem
Lithographic printing plates face issues with ablation debris formation due to inhomogeneous distribution and aggregation of infrared dyes, leading to reduced performance and contamination of exposure devices, despite previous attempts to minimize ablation through optimized coating compositions and barrier layers which often compromise developability.
Innovation Solution
A positive-working lithographic printing plate precursor with a coating containing an infrared-absorbing compound having a specific chromophoric structure, which absorbs infrared radiation and converts it into heat, minimizing ablation and maintaining high developability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional infrared dyes are used in the coating, then the coating can be imaged by infrared laser exposure, but the dyes aggregate and cause ablation debris formation that contaminates exposure devices
Solution Approach 1:
The patent modifies the chemical structure of the infrared absorbing compound by introducing a specific chromophoric structure with particular molecular characteristics. This structural parameter change improves solubility and distribution uniformity in the coating, preventing aggregation that leads to ablation debris while maintaining infrared absorption capability for imaging
Solution Approach 2:
The patent uses a composite coating system comprising the specifically structured infrared absorbing compound combined with phenolic resin binders and other coating components. This composite formulation ensures uniform distribution of the infrared dye throughout the coating matrix, preventing aggregation and subsequent ablation debris formation during laser exposure
2Object-generated harmful factors
If barrier layers are added to reduce ablation, then ablation debris is minimized, but developability of the coating is compromised
Solution Approach 1:
The patent removes the need for separate barrier layers by incorporating ablation prevention functionality directly into the infrared absorbing compound's molecular structure. The improved solubility and distribution characteristics of the modified dye inherently prevent aggregation and ablation debris formation without requiring additional protective layers that would interfere with developer access
Solution Approach 2:
The specifically structured infrared absorbing compound serves multiple functions simultaneously: it absorbs infrared radiation for imaging, distributes uniformly to prevent aggregation, and inherently reduces ablation debris formation. This multi-functionality eliminates the need for separate barrier layers, maintaining coating developability while preventing ablation
3Object-generated harmful factors
If the coating is optimized to minimize ablation, then ablation debris is reduced, but printing performance and developability deteriorate
Solution Approach 1:
The patent optimizes multiple parameters of the infrared absorbing compound including molecular structure, chromophoric characteristics, and solubility properties. These parameter changes are specifically tuned to achieve uniform distribution in the coating while maintaining strong infrared absorption for imaging and resistance to ablation, all without compromising printing performance
Solution Approach 2:
The patent achieves different functional properties in different regions of the coating through uniform molecular distribution. The specifically structured infrared absorbing compound provides localized uniformity at the molecular level, ensuring consistent imaging performance, ablation resistance, and developability throughout the entire coating without requiring separate functional layers
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 solution significantly reduces ablation debris generation while maintaining excellent printing performance and developability, as evidenced by reduced ablation levels and comparable exposure energies across tested samples.
Implementation Method 1
an infrared-absorbing compound having a specific chromophoric structure, which absorbs infrared radiation and converts it into heat
Implementation Method 2
converts it into heat, minimizing ablation
Data Source
AI summary
A positive-working lithographic printing plate precursor is disclosed wherein the coating is optimized for producing a minimum extent of ablation when exposed to heat and/or light. The coating includes an infrared absorbing agent which contains a structural element according to Formula I: wherein A represents -S-R1 wherein R1 represents an optionally substituted alkyl, aralkyl, alkaryl, cycloalkyl, alkenyl, alkynyl, aryl, or heteroaryl group, and/or combinations thereof and Q = -CHR'-CHR"-, -CR'=CR"- or -CHR'-CHR"-CHR"'- and R', R" and R"' independently represent hydrogen, an alkyl, cycloalkyl, aralkyl, alkaryl, aryl or heteroaryl group, or R' and R" or R" and R"' form together a cyclic structure.