Lithographic Printing Plate Precursor On-Press Development
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Solution Overview
Problem
Conventional lithographic printing plate precursors for on-press development suffer from inadequate image strength and printing durability, despite advancements in image-forming properties and physical properties, and existing methods fail to adequately address environmental concerns related to waste liquid disposal during development processing.
Innovation Solution
A lithographic printing plate precursor is developed with a specific composition including a support, an image-recording layer containing a polymerizable compound, fine polymer particles, an infrared absorbing agent, and a polymerization initiator, along with an overcoat layer containing an inorganic stratiform compound, and an undercoat layer with a polymer compound having a support-adsorbing group and polymerizable group, which enhances on-press development properties and printing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lithographic printing plate precursor uses hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder for on-press development, then on-press development property is improved, but image strength and printing durability become extremely weak and insufficient
Solution Approach 1:
The patent uses a composite material system consisting of hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder. The hydrophobic polymer particles (such as polyethylene, polypropylene, or their copolymers) provide the on-press development property by being removable with dampening water, while the hydrophilic binder (such as gelatin, polyvinyl alcohol, or carboxymethyl cellulose) provides structural integrity and image strength. This composite structure allows the plate to undergo on-press development while maintaining sufficient printing durability.
2Strength
If conventional development processing is used, then image strength and printing durability are maintained, but environmental problems arise from waste liquid discharge
Solution Approach 1:
The patent extracts and eliminates the harmful development processing step from the traditional lithographic plate making process. By designing the image-recording layer with hydrophobic thermoplastic polymer particles that can be directly removed by dampening water during on-press development, the patent removes the need for separate chemical development steps that generate harmful waste liquids, thereby solving the environmental problem while maintaining printing durability.
3Productivity
If laser exposure is used for CTP technology, then plate making efficiency is improved, but image-forming property and physical property require further improvement
Solution Approach 1:
The patent optimizes the physical and chemical parameters of the image-recording layer to improve image-forming property and physical property while maintaining CTP efficiency. This includes controlling the particle size distribution of hydrophobic polymer particles (0.1-2.0 μm), optimizing the concentration ratio of hydrophobic polymer to hydrophilic binder, selecting appropriate molecular weights and crosslinking densities, and adjusting the composition of the hydrophilic binder to achieve both high laser sensitivity and excellent mechanical properties for durable printing.
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 precursor with improved on-press development properties and printing durability, while also simplifying the development process and reducing environmental impact by using a method that allows for image recording with laser exposure and on-press development without the need for conventional development processing.
Implementation Method 1
the image-recording layer contains (A) a polymerizable compound represented by formula (1), (B) a fine polymer particle containing a structural unit represented by formula (2) and a structural unit represented by formula (3), (C) an infrared absorbing agent and (D) a polymerization initiator
Implementation Method 2
a lithographic printing plate precursor capable of undergoing a direct plate making by image exposure with laser
Implementation Method 3
the image-recording layer contains (A) a polymerizable compound represented by formula (1), (B) a fine polymer particle containing a structural unit represented by formula (2) and a structural unit represented by formula (3), (C) an infrared absorbing agent and (D) a polymerization initiator
Implementation Method 4
an overcoat layer in this order
Implementation Method 5
an undercoat layer with a polymer compound having a support-adsorbing group and polymerizable group
Data Source
AI summary
A lithographic printing plate precursor includes, in the following order: a support; an image-recording layer which is capable of being removed with at least one of printing ink and dampening water and contains a polymerizable compound represented by the formula (1) as defined herein, a polymer particle containing a structural unit represented by the formula (2) as defined herein and a structural unit represented by the formula (3) as defined herein, an infrared absorbing agent and a polymerization initiator; and an overcoat layer.