Negative-Working Lithographic Plates With Zwitterionic Core-Shell Particles
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Solution Overview
Problem
There is a need to improve the properties of negative-working lithographic printing plate precursors, particularly to increase photospeed and facilitate clean development without requiring excessive energy for exposure and image formation.
Innovation Solution
A negative-working imageable element comprising a substrate with an imageable layer containing a free radically polymerizable component, an initiator composition, a radiation absorbing compound, polymeric binders, and core-shell particles with a hydrophobic polymeric core and a hydrophilic polymeric shell covalently bound to the core, where the shell includes zwitterionic functional groups, enabling improved stability and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional radiation-sensitive compositions are used for negative-working printing plates, then the composition can be imaged and developed, but excessive energy is required for exposure and photospeed is insufficient
Solution Approach 1:
The patent introduces core-shell particles with zwitterionic functional groups that change the physical-chemical parameters of the radiation-sensitive composition. These particles modify the polymerization kinetics and radiation absorption characteristics, enabling efficient exposure at lower energies while maintaining negative-working functionality.
Solution Approach 2:
The invention employs composite core-shell particles combining hydrophobic polymeric cores with hydrophilic shells containing zwitterionic groups. This composite structure creates synergistic effects that enhance both radiation sensitivity and polymerization efficiency, resolving the contradiction between energy consumption and photospeed.
2Stability of the object's composition
If the imageable layer is made stable in solvent mixtures, then development cleanliness is improved, but photospeed may be reduced
Solution Approach 1:
The core-shell particles exhibit local quality differentiation with hydrophobic cores providing structural stability and hydrophilic zwitterionic shells providing solvent compatibility. This localized functional differentiation allows the composition to maintain both stability in solvent mixtures for clean development and high photospeed for efficient exposure.
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 use of core-shell particles with zwitterionic functional groups enhances the stability of the imageable elements in solvent mixtures and significantly improves photospeed, allowing for efficient exposure and development of lithographic printing plates with reduced energy requirements.
Implementation Method 1
an initiator composition capable of generating radicals sufficient to initiate polymerization of the free radically polymerizable component upon exposure to imaging radiation
Implementation Method 2
a radiation absorbing compound
Data Source
AI summary
Negative-working imageable elements have an imageable layer comprising a free radically polymerizable component, an initiator composition capable of generating radicals sufficient to initiate polymerization of the free radically polymerizable component upon exposure to imaging radiation, a radiation absorbing compound, one or more polymeric binders, and at least 5 weight % of core-shell particles comprising a hydrophobic polymeric core and a hydrophilic polymeric shell that is covalently bound to the polymeric core. The hydrophilic polymeric shell has one or more zwitterionic functional groups. These elements can be imaged such as by IR lasers to provide lithographic printing plates.