Lithographic Printing Plate Precursor Storage Stability
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Solution Overview
Problem
Photopolymer printing plate precursors often suffer from reduced sensitivity and increased tendency to toning and defects during storage, leading to poor shelf life and incomplete removal of non-exposed areas during processing.
Innovation Solution
A heat-sensitive printing plate precursor is developed using a photopolymerisable composition comprising a trihaloalkyl sulfone initiator and a borate compound, which stabilizes the coating upon exposure and prevents degradation, allowing for improved polymerization and reduced pinhole formation during long-term storage and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If photopolymer printing plate precursors are stored for extended periods, then shelf life is improved, but sensitivity decreases and toning/defects increase
Solution Approach 1:
The patent changes the chemical parameters of the coating composition by incorporating specific stabilizers and antioxidants that prevent degradation during storage. This allows the plate precursor to maintain its sensitivity and performance characteristics over extended storage periods without the typical deterioration seen in conventional photopolymer systems.
Solution Approach 2:
The invention uses a composite coating formulation that combines photopolymerizable compounds with stabilizing agents and specific initiator systems. This composite structure provides both the necessary reactivity for image formation and the stability required for long-term storage without sensitivity loss or toning defects.
2Ease of manufacture
If conventional photopolymer coatings are used, then manufacturing simplicity is maintained, but incomplete removal of non-exposed areas occurs
Solution Approach 1:
The patent modifies the chemical parameters of the coating by incorporating specific photopolymerizable compounds and initiator systems that enhance the contrast between exposed and non-exposed areas. This allows for more complete removal of non-exposed areas during development while maintaining the simplicity of the coating application process.
Solution Approach 2:
The coating formulation includes pre-selected photopolymerizable compounds and initiators that are designed to provide optimal development characteristics. This preliminary optimization of the coating composition ensures that during the development process, non-exposed areas are completely removed while exposed areas remain intact, achieving high image clarity without complex manufacturing steps.
3Stability of the object's composition
If storage stability is improved, then defect formation is reduced, but processing complexity increases
Solution Approach 1:
The patent combines multiple functions into the coating formulation itself by incorporating stabilizers, photopolymerizable compounds, and initiators in specific ratios. This integration provides both storage stability and processability within a single coating layer, eliminating the need for additional separate processing steps to achieve defect-free results.
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 provides excellent sensitivity and storage stability, with reduced formation of defects and toning, enabling high-quality printing with extended shelf life and improved cohesive strength of the printing plate.
Implementation Method 1
Photopolymer printing plates rely on a working-mechanism whereby the coating—which typically includes free radically polymerisable compounds—hardens upon exposure. 'Hardens' means that the coating becomes insoluble or non-dispersible in the developing solution and may be achieved through polymerization and/or crosslinking of the photosensitive coating upon exposure to light.
Implementation Method 2
A heat-sensitive printing plate precursor is developed using a photopolymerisable composition comprising a trihaloalkyl sulfone initiator and a borate compound, which stabilizes the coating upon exposure and prevents degradation
Implementation Method 3
Optionally, the exposure step is followed by a heating step to enhance or to speed-up the polymerization and/or crosslinking reaction.
Data Source
AI summary
A lithographic printing plate precursor is disclosed including a coating comprising a polymerisable compound, an infrared absorbing dye, a photoinitiator including a trihaloalkyl group and a borate compound.