Lithographic Printing Plate Precursor with Localized Hydrophilic Surface
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Solution Overview
Problem
Lithographic printing plate precursors face challenges in achieving both high printing durability and stain resistance, particularly over time, while also requiring environmentally friendly development processes that minimize waste and use of high alkaline developers.
Innovation Solution
A lithographic printing plate precursor is developed with a support and an image-recording layer containing a polymerization initiator, sensitizing dye, and polymerizable compound, where the image-recording layer or undercoat layer includes a polymer compound with specific repeating units that enhance hydrophilicity and adhesion, allowing for radical polymerization and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the support surface is made highly hydrophilic to enable development with low pH or dampening water, then development simplicity is improved, but the image area is removed from the support by dampening water during printing, reducing printing durability
Solution Approach 1:
The invention applies different surface properties to different areas of the support. The non-image area is made highly hydrophilic to enable simple development with dampening water, while the image area is made hydrophobic through the photopolymerizable layer to prevent ink adhesion and ensure printing durability. This local differentiation resolves the contradiction between development simplicity and printing durability.
2Object-affected harmful factors
If the support surface is made hydrophobic to prevent ink adhesion on non-image area, then stain resistance is improved, but the non-image area cannot be effectively developed with dampening water
Solution Approach 1:
The invention creates a clear spatial differentiation of surface properties: the non-image area has high hydrophilicity for effective development with dampening water, while the image area has hydrophobicity for stain resistance. This local quality differentiation allows both requirements to be satisfied simultaneously without compromise.
3Ease of manufacture
If conventional high alkaline developer is used to remove unnecessary image-recording layer, then development effectiveness is improved, but environmental pollution from waste liquid increases
Solution Approach 1:
The invention changes the pH parameter of the development system from high alkaline (conventional) to near-neutral or slightly acidic (aqueous solution with pH 7-11). This parameter change maintains development effectiveness while eliminating the environmental pollution associated with high alkaline waste liquid, satisfying both development effectiveness and environmental friendliness requirements.
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 a lithographic printing plate with excellent stain resistance, printing durability, and developing properties, even after extended use, while enabling development with aqueous solutions of pH 11 or less, thus addressing environmental concerns and simplifying the plate-making process.
Implementation Method 1
an image-recording layer containing (A) a polymerization initiator, (B) a sensitizing dye and (C) a polymerizable compound
Implementation Method 2
a sensitizing dye and (C) a polymerizable compound
Data Source
Figure 1
AI summary
A lithographic printing plate precursor includes: a support; and an image-recording layer containing (A) a polymerization initiator, (B) a sensitizing dye and (C) a polymerizable compound, and the image-recording layer or an undercoat layer which is optionally provided between the support and the image-recording layer comprises (D) a polymer compound comprising (a1) a repeating unit having a side chain having a structure represented by the following formula (a1-1) and (a2) a repeating unit having a side chain having at least one structure of the formulae (a2-1), (a2-2), (a2-3), (a2-4), (a2-5) and (a2-6) as defined herein.