Lithographic Printing Plate Precursor UV Absorber Distribution
Solution Overview
Problem
Lithographic printing plate precursors using on-press development methods face challenges with fog generation under mercury lamps, leading to deteriorated removability of unexposed areas, especially when using ultraviolet absorbing agents in oxygen-blocking layers or microcapsules, which are not effective for radical polymerization types.
Innovation Solution
A lithographic printing plate precursor with an image-recording layer containing an infrared absorbing agent, radical polymerization initiator, radical polymerizable compound, polymer compound with a polyoxyalkylene structure, and an ultraviolet absorbing agent, where the ultraviolet absorbing agent has an alkyl group with 8 to 20 carbon atoms and is incorporated into polymer fine particles, enhancing handling properties under mercury lamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an ultraviolet absorbing agent is incorporated into an oxygen-blocking layer or microcapsules to prevent fog generation, then handling stability under mercury lamps is improved, but on-press development property deteriorates because these locations are not effective for radical polymerization types
Solution Approach 1:
The ultraviolet absorbing agent is extracted from the oxygen-blocking layer or microcapsules and relocated to the image-recording layer itself, where it can simultaneously protect against UV-induced fog and maintain on-press development effectiveness through proximity to the radical polymerization sites
Solution Approach 2:
The image-recording layer is given dual functionality: it serves both as the site for radical polymerization (on-press development) and as the location for ultraviolet absorption (fog prevention), eliminating the need for separate components that compromise either function
2Ease of manufacture
If a lithographic printing plate precursor uses on-press development method, then the wet treatment process is simplified and environmental impact is reduced, but fog generation occurs under mercury lamps leading to deteriorated removability of unexposed areas
Solution Approach 1:
The ultraviolet absorbing agent is incorporated into the image-recording layer before exposure to prevent UV-induced fog generation, thereby preserving the removability of unexposed areas even when handling under mercury lamps during the simplified on-press development process
3Stability of the object's composition
If the ultraviolet absorbing agent is uniformly distributed in the image-recording layer, then handling property under mercury lamps is improved and fog is prevented, but the concentration must be precisely controlled to maintain balance between printing durability and development efficiency
Solution Approach 1:
The concentration of the ultraviolet absorbing agent is optimized within a specific range (0.01-10% by weight) to achieve the desired balance between fog prevention, handling stability, and maintenance of printing durability and development efficiency, avoiding the need for precise control at very low concentrations
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 prevents deterioration of on-press development properties and maintains excellent handling under mercury lamps, achieving a good balance between printing durability and development efficiency by uniformly distributing the ultraviolet absorbing agent within the image-recording layer.
Implementation Method 1
an ultraviolet absorbing agent (E) and being capable of forming an image by supplying at least one of printing ink and dampening water on a printing machine after imagewise exposure to remove an unexposed area of the image-recording layer
Implementation Method 2
a radical polymerization initiator (B), (C) a radical polymerizable compound
Data Source
AI summary
A lithographic printing plate precursor, comprising a support having thereon an image-recording layer containing (A) an infrared absorbing agent, (B) a radical polymerization initiator, (C) a radical polymerizable compound, (D) a polymer compound containing a polyoxyalkylene structure and (E) an ultraviolet absorbing agent and being capable of forming an image by supplying at least one of printing ink and dampening water on a printing machine after imagewise exposure to remove an unexposed area of the image-recording layer.