Lithographic Printing Plate Precursor Protective Layer
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Solution Overview
Problem
Conventional lithographic printing plate precursors face issues with ink receptivity and printing durability, particularly when using special color ink, due to hydrophilic components in the protective layer interacting with the image-recording layer, leading to deterioration of ink receptivity after preservation.
Innovation Solution
A lithographic printing plate precursor is developed with a protective layer containing a hydrophilic polymer with specific repeating units, which inhibits mixing with the image-recording layer components, ensuring good ink receptivity and high printing durability, even after preservation, by using a hydrophilic polymer with repeating units represented by formulas (1) and (2), and optionally an inorganic stratiform compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hydrophilic protective layer is used to facilitate development processing, then development is simplified, but ink receptivity deteriorates due to hydrophilic components mixing with the image-recording layer
Solution Approach 1:
The patent introduces a hydrophobic polymer as an intermediary substance in the protective layer that acts as a barrier between the hydrophilic development facilitators and the image-recording layer. This intermediary component prevents harmful mixing while allowing beneficial development processes to occur, thus resolving the contradiction between ease of development and ink receptivity maintenance
Solution Approach 2:
The protective layer is designed as a composite material containing both hydrophilic components (for easy development) and hydrophobic components (for preventing mixing with image-recording layer). This composite structure allows the layer to simultaneously provide facilitation of development processing and maintenance of ink receptivity by combining materials with opposing properties in a synergistic formulation
2Device complexity
If conventional hydrophilic protective layers are used, then development processing is simplified, but printing durability deteriorates after preservation
Solution Approach 1:
The patent extracts and isolates the hydrophobic polymer component within the protective layer formulation, giving it a specific functional role separate from traditional hydrophilic developers. This extracted hydrophobic element specifically addresses printing durability by preventing premature interaction between the protective layer and ink, while the overall composite structure maintains processing simplicity
Solution Approach 2:
The protective layer employs a composite material system where hydrophobic and hydrophilic components work together to simultaneously achieve simplified processing and enhanced printing durability. The composite formulation allows the layer to remain stable during preservation (maintaining printing durability) while still facilitating development when processed (maintaining processing simplicity)
3Ease of manufacture
If the protective layer contains hydrophilic components, then development is facilitated, but ink density decreases due to interaction with the image-recording layer
Solution Approach 1:
The hydrophobic polymer serves as an intermediary barrier that prevents direct contact and interaction between hydrophilic components in the protective layer and the image-recording layer. This intermediary action maintains ink density by blocking the migration of hydrophilic substances into the image area, while still allowing the protective layer to facilitate development through its overall composition and structure
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 ink receptivity and high printing durability, particularly with special color ink, by preventing the interaction between the protective and image-recording layers, maintaining ink density and extending the printing capability without significant ink receptivity loss.
Implementation Method 1
contains (E) a hydrophilic polymer which contains a repeating unit represented by formula (1) and a repeating unit represented by formula (2) and the sum of these two repeating units is at least 95% by mole based on the total repeating units constituting the polymer
Implementation Method 2
contains (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound
Implementation Method 3
contains (B) a polymerization initiator, (C) a polymerizable compound and forms an image by removing an unexposed area
Data Source
AI summary
A lithographic printing plate precursor includes, in the following order: a support; an image-recording layer which is capable of forming an image by removing an unexposed area by an automatic development processor in the presence of a developer having pH of from 2 to 14 after exposure and contains (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound and (D) a polymer which is insoluble in water and alkali-soluble; and a protective layer, and the protective layer contains (E) a hydrophilic polymer which has a repeating unit represented by the formula (1) as defined herein and a repeating unit represented by the formula (2) as defined herein and a sum of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) is at least 95% by mole based on total repeating units constituting the polymer.