IR-Sensitive Lithographic Printing Plate Precursors for Stable Printout

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing on-press developable lithographic printing plate precursors face challenges in achieving strong and stable printout images with adequate durability and image contrast, particularly under lower exposure energy levels, which is essential for high productivity and compatibility with press automation.

Innovation Solution

A lithographic printing plate precursor comprising a substrate with an infrared radiation-sensitive image-recording layer containing a free radical initiator, an electron-donating agent, and a color-changing compound represented by Structure (I), which generates free radicals upon infrared exposure, enabling stable printout images with good contrast and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional acid generator and acid-sensitive color precursor compositions are used for infrared radiation imaging, then the imaging process can be completed, but the printout image is not strong enough and fades after imaging due to limited acid generation efficiency and chemical equilibration

Engineering Contradiction:

Improveprintout image stabilityVSAvoidprintout contrast

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the chemical parameters of the imaging composition by replacing conventional acid-sensitive color precursors with compounds containing specific functional groups (carboxyl, sulfonic acid, phosphonic acid, or phosphinic acid groups) that exhibit enhanced sensitivity to protonation. This parameter change in chemical structure enables stronger and more stable printout images upon infrared radiation exposure

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite imaging system combining infrared radiation-absorbing compounds with free radical initiator compositions and proton-releasing compounds. This composite approach integrates multiple functional components that work synergistically to generate stable printout images through free radical polymerization and enhanced acid generation mechanisms

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If higher exposure energy is used to strengthen printout, then image contrast improves, but productivity decreases and compatibility with press automation is reduced

Engineering Contradiction:

Improveprintout contrastVSAvoidimaging speed

Core Design Contradiction:

Illumination intensityVSProductivity

Solution Approach 1:

The patent modifies the exposure energy parameters by using compositions that are highly sensitive to infrared radiation, enabling effective imaging at lower energy levels (e.g., 50-200 mJ/cm²). This parameter optimization allows compatibility with press automation systems while maintaining strong printout contrast

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional acid-generation mechanisms with free radical initiator compositions that respond to infrared radiation. This substitution creates a more efficient energy conversion pathway that achieves better printout at lower exposure energies, improving productivity and automation compatibility

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Loss of time

If on-press development is implemented, then processing time and chemical usage are reduced, but achieving adequate printout stability becomes more difficult

Engineering Contradiction:

Improveprocessing timeVSAvoidprintout stability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent incorporates free radical initiator compositions and proton-releasing compounds into the image-recording layer beforehand. These components are pre-positioned to react immediately upon infrared exposure, generating stable printout images that can be directly developed on-press without requiring extended processing times or additional chemical treatments

Inventive Principle:

Principle #10Preliminary action

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 precursor achieves stable printout images with high ΔE values and improved image durability, suitable for press automation, without adverse effects on imaging speed or developability, using lower exposure energy.

Implementation Method 1

a free radical initiator composition that is capable of generating free radicals upon exposure to infrared radiation

Methodology Applied

Scientific EffectPhotodissociation: Photodissociation

Implementation Method 2

a color-changing compound that is represented by the following Structure (I)... The precursor achieves stable printout images with high ΔE values

Methodology Applied

Scientific EffectPhotochromism: Photochromism

Data Source

PatentUS12436459B2Lithographic printing plate precursor and method of use

Publication Date: 2025.10.07 EASTMAN KODAK CO

AI summary

IR-sensitive lithographic printing plate precursors provide a stable print-out image using a unique IR radiation-sensitive composition in an infrared radiation-sensitive image-recording layer. This IR radiation-sensitive composition includes: (1) a free radical initiator composition that comprises an electron-donating agent; (2) a free radically polymerizable composition; and (3) a color-changing compound that is represented by the Structure (I) having a conjugated carbon chain between the aromatic terminal groups. The compound also has a —SO2—R3 group wherein R3 represents alkyl, aryl or heteroaryl groups. After IR imaging, these precursors exhibit desirable printout images both fresh and after dark storage. The precursors can be developed off-press or on-press.