Silicone Composition for Printing Plates Adhesion Ink Repellency
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Solution Overview
Problem
Existing planographic printing plates face challenges with adhesion to underlying layers due to fast-curing silicone rubber layers, leading to weak ink repellency and scratch resistance, particularly when using addition reaction type silicone rubber layers with silane coupling agents, which compromise both adhesion and ink repellency.
Innovation Solution
A silicone composition incorporating a SiH group-containing compound, a compound with an acetoxy or dialkyloximino group capable of hydrosilylation, and another compound with a non-hydrolyzable functional group, optimized to balance adhesion and ink repellency, is used to form a silicone rubber layer that is both fast-curing and resistant to scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an addition reaction type silicone rubber layer is used for fast curing, then the curing speed is improved, but the adhesion to the underlying layer becomes extremely weak
Solution Approach 1:
The silicone rubber layer is divided into two distinct layers: a lower adhesion-promoting layer containing silane coupling agents that bond to the underlying layer, and an upper ink-repellent layer containing fluorine resin for fast curing and ink repellency. This segmentation allows each layer to specialize in its function without compromising the other.
Solution Approach 2:
The invention uses composite materials by combining silicone rubber with silane coupling agents in the adhesion layer, and fluorine resin with crosslinking agents in the ink-repellent layer. This composite approach enables simultaneous achievement of fast curing, strong adhesion, and excellent ink repellency through material composition rather than relying on a single material's properties.
2Strength
If a silane coupling agent containing an unsaturated group is added to improve adhesion, then the adhesive strength is improved, but the ink repellency is reduced
Solution Approach 1:
The silane coupling agent is segregated to the lower adhesion-promoting layer only, while the upper ink-repellent layer contains fluorine resin and crosslinking agents but no silane coupling agent. This spatial segmentation ensures that the unsaturated groups in the silane coupling agent do not interfere with ink repellency in the upper layer, while still providing strong adhesion in the lower layer.
Solution Approach 2:
Different regions of the silicone rubber layer are given different compositions: the lower layer has high silane coupling agent content for maximum adhesion, while the upper layer has fluorine resin dominance for maximum ink repellency. This local quality differentiation resolves the contradiction by optimizing each region for its specific function.
3Strength
If a condensation reaction type silicone rubber layer is used, then the adhesion is improved, but the curing speed becomes slow and requires cover film removal operations
Solution Approach 1:
The invention segments the curing function from the adhesion function. The lower adhesion layer uses silane coupling agents that can cure via multiple mechanisms including moisture-curing and crosslinking, providing strong bond without requiring slow condensation reactions. The upper layer uses fast-curing addition reaction chemistry with fluorine resin, eliminating the need for cover films and enabling high productivity.
Solution Approach 2:
The lower adhesion layer acts as an intermediary between the underlying layer and the upper ink-repellent layer. It provides the bonding function that would otherwise require slow condensation curing, while allowing the upper layer to achieve fast curing without cover films. This intermediary layer mediates between the conflicting requirements of adhesion and fast curing.
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 silicone composition achieves excellent adhesion to underlying layers while maintaining excellent ink repellency and scratch resistance, addressing the limitations of prior art by balancing these properties in a single silicone rubber layer.
Implementation Method 1
a compound represented by the general formula (I); and a compound represented by the general formula (II); wherein Ds in the compound represented by the general formula (I) and Gs in the compound represented by the general formula (II) each represents an acetoxy group or a dialkyloximino group
Data Source
Figure 1
AI summary
The present invention provides a silicone composition for use in a printing plate, the composition including at least: a SiH group-containing compound; a compound represented by the following general formula (I); a compound represented by the following general formula (II); and/or a compound represented by the following general formula (III); wherein Ds in the compound represented by the general formula (I), Gs in the compound represented by the general formula (II) and Js in the compound represented by the general formula (III) each represents an acetoxy group or a dialkyloximino group: A-Si-(D)3 (I) (wherein in the general formula (I), A represents a non-hydrolyzable functional group capable of undergoing a hydrosilylation reaction with a SiH group); E-Si-(G)3 (II) (wherein in the general formula (II), E represents a non-hydrolyzable functional group incapable of undergoing a hydrosilylation reaction with a SiH group); and Si-(J)4 (III). An object of the present invention is to provide a silicone composition for use in a printing plate, for obtaining a planographic printing plate precursor or a planographic printing plate which includes a silicone rubber layer having an excellent adhesion to an underlying layer despite being a fast-curing silicone rubber layer, and which has an excellent ink repellency and scratch resistance.