Lithographic Printing Plate Precursor Gas Generation for Chemical-Free Development

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Solution Overview

Problem

Current methods for achieving high-resolution lithographic printing plates using chemical-free developing techniques are inadequate, as they fail to provide sufficient sensitivity and solvent resistance, with previous approaches either underperforming in resolution or compromising solvent resistance.

Innovation Solution

A lithographic printing plate precursor comprising a substrate, a heat-sensitive layer, and an ink repellent layer, where the heat-sensitive layer includes a polymer, a near-infrared absorbing compound, and an easily heat-decomposable compound, optimized for gas generation and adhesion properties, allowing for high-resolution imaging without chemical solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If air bubbles are incorporated in the heat-sensitive layer to decrease thermal conductivity and suppress heat diffusion, then sensitivity to laser beams is improved, but adhesion between the heat-sensitive layer and silicone layer deteriorates

Engineering Contradiction:
ImprovesensitivityVSAvoidadhesion
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent changes the physical and chemical parameters of the heat-sensitive layer by incorporating specific compounds (azo compounds, hydrazine compounds, or their mixtures) that decompose at controlled temperatures. This allows precise control over the decomposition temperature to balance thermal conductivity reduction with adhesion maintenance, resolving the contradiction between sensitivity improvement and adhesion deterioration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite heat-sensitive layer containing multiple components: polymer matrix, azo compounds, hydrazine compounds, and their mixtures. This composite structure enables simultaneous achievement of low thermal conductivity (for sensitivity) and controlled adhesion properties through the synergistic interaction of different materials with specific decomposition characteristics.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If metal-containing organic substances are incorporated to generate decomposition gas and decrease adhesion, then sensitivity is improved, but solvent resistance deteriorates

Engineering Contradiction:
ImprovesensitivityVSAvoidsolvent resistance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent carefully controls the decomposition temperature parameter of the heat-sensitive layer by selecting specific azo and hydrazine compounds with defined thermal stability ranges. This parameter control ensures that decomposition occurs at temperatures that generate sufficient gas for sensitivity improvement while maintaining solvent resistance by preventing premature decomposition that would compromise layer integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating zones with different decomposition characteristics within the heat-sensitive layer. The azo and hydrazine compounds are distributed to provide localized gas generation at specific depths or regions, enabling sensitivity improvement in the laser-irradiated portion while maintaining overall solvent resistance through controlled spatial distribution of functional materials.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If heat-sensitive layer composition is optimized for gas generation to improve sensitivity, then resolution is improved, but structural integrity deteriorates

Engineering Contradiction:
ImproveresolutionVSAvoidstructural integrity
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent employs a composite material system consisting of polymer matrices combined with azo compounds, hydrazine compounds, and their mixtures. This composite structure provides both the gas generation capability needed for high resolution and the structural stability required for maintaining integrity, as each component contributes specific properties that complement the others.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent incorporates azo and hydrazine compounds that serve as preemptive cushioning agents. These compounds are designed to decompose at controlled temperatures before the main imaging process, generating gas that prevents excessive adhesion and maintains structural integrity during subsequent processing steps, thereby cushioning against potential structural failures.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 enables high-resolution imaging with improved solvent and peeling resistance, achieving effective chemical-free development while maintaining structural integrity and print quality.

Implementation Method 1

light exposure of waterless lithographic printing plates is performed mainly by the laser-induced photothermal conversion technique that causes a thermal reaction to break the heat-sensitive layer

Methodology Applied
Scientific EffectPhotothermal conversion: Absorption (EM radiation)

Implementation Method 2

the incorporation of a metal-containing organic substance serving as a heat-decomposable compound in the heat-sensitive layer of a direct imageable waterless printing plate precursor so that decomposition gas is generated in the laser irradiated portion

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentEP3783435B1Lithographic printing original plate, method for manufacturing lithographic printing plate, and method for manufacturing prints using same
Publication Date: 2022.02.09 TORAY INDUSTRIES INC

AI summary

The present invention provides a lithographic printing plate precursor including at least a heat-sensitive layer and an ink repellent layer disposed on a substrate, the rate of gas generation therefrom being 6.5 x 105 g/m3 to 12.5 x 105 g/m3 as determined by GC-MS analysis in which the lithographic printing plate precursor is heated in a nitrogen stream at 450°C for 5 minutes, and also provides a method for producing a lithographic printing plate and a method for producing printed matter therefrom.