Infrared Printing Plate Backcoat Solvent Control
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Solution Overview
Problem
Infrared-sensitive planographic printing plate precursors face issues with mechanical strength and adhesion defects when stacked without interleaf sheets, leading to scratching and peeling during transportation and handling.
Innovation Solution
A planographic printing plate precursor with a water-insoluble and alkali-soluble resin recording layer and an organic polymer layer on a support, where the organic polymer layer has a solvent content of 10 mg or less per gram, formed using low boiling point solvents and controlled drying conditions to prevent adhesion and scratching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If planographic printing plate precursors are stacked without interleaf sheets, then packaging cost is reduced and handling is simplified, but mechanical damage and scratching of the photosensitive layer occurs during transportation
Solution Approach 1:
A backcoat layer comprising an organic polymer is applied to the back surface of the support (opposite to the photosensitive layer) to serve as a protective intermediary. This backcoat prevents direct contact between photosensitive layers of stacked precursors, eliminating scratching while allowing cost-effective stacking without interleaf sheets. The organic polymer provides a smooth, non-abrasive surface that protects the photosensitive layer during handling and transportation.
Solution Approach 2:
The invention controls the solvent content in the organic polymer backcoat to 10 mg/g or less through specific drying conditions. This parameter control prevents adhesion between stacked precursors while maintaining the protective function against mechanical damage. By precisely controlling solvent residue, the backcoat remains stable and non-sticky under various storage conditions including high humidity.
2Strength
If inorganic pigments such as silica gel are contained in the backcoat layer, then mechanical strength is improved, but scratching of photosensitive layers occurs during transportation
Solution Approach 1:
The invention changes the composition parameter of the backcoat from inorganic pigments to organic polymers. The organic polymer provides sufficient mechanical strength while presenting a smooth surface that does not scratch the photosensitive layer. This compositional change eliminates the harmful scratching effect while maintaining the necessary structural integrity of the backcoat layer.
3Object-affected harmful factors
If a matte surface is provided by electrostatic spraying, then adhesion during stacking is reduced, but scratching protection is insufficient under high humidity conditions
Solution Approach 1:
The invention uses a composite structure where an organic polymer backcoat is applied to the support back surface. This organic polymer layer combines the properties of reduced adhesion (through controlled solvent content and surface characteristics) with reliable scratching protection (through the polymer's inherent mechanical properties). The composite approach ensures consistent performance across varying humidity conditions.
4Object-affected harmful factors
If the organic polymer layer contains high solvent content, then adhesion between stacked precursors increases, but if solvent content is reduced, then the organic polymer layer may become brittle
Solution Approach 1:
The invention optimizes the solvent content parameter to 10 mg/g or less, which is low enough to prevent adhesion between stacked precursors but maintained at a level that preserves the flexibility of the organic polymer layer. This precise parameter control balances the competing requirements of non-adhesion and mechanical flexibility.
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 effectively suppresses scratching and adhesion defects, ensuring the integrity of the recording layer during transportation and handling without interleaf sheets, even under high humidity conditions and in autoloader exposure devices.
Implementation Method 1
an organic polymer layer provided on or above the other surface of the support, wherein when the organic polymer layer is formed, at least one solvent is used, and a total amount of the solvent remaining in the organic polymer layer is 10 mg per gram of the organic polymer or less
Implementation Method 2
an infrared absorbent which absorbs light and generates heat. In unexposed portions (i.e., an image area), the infrared absorbent acts as a dissolution inhibitor, which interacts with the alkali-soluble resin to substantially lower the solubility of the alkali-soluble resin. On the other hand, in exposed portions (i.e., a non-image area), the interaction of the infrared absorbent and the alkali-soluble resin becomes weak due to the heat generated
Data Source
AI summary
An infrared-sensitive planographic printing plate precursor including: a support; a recording layer capable of forming an image through infrared irradiation provided on or above one surface of the support, the recording layer containing a resin, which is water-insoluble and alkali-soluble, and an infrared absorbent; and an organic polymer layer provided on or above the other surface of the support, wherein when the organic polymer layer is formed, a solvent is used, and the total amount of solvent remaining in the organic polymer layer is 10 mg per gram of the organic polymer or less is provided.