Photopolymerizable Flexographic Printing Elements Hardness Anisotropy
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Solution Overview
Problem
Existing photopolymerizable flexographic printing elements struggle to produce high-quality, hard flexographic printing plates with a large tonal value range and small tonal value increase, while maintaining isotropic behavior and acceptable raw layer plasticity, due to limitations in hardness and anisotropy issues.
Innovation Solution
A photopolymerizable flexographic printing element comprising a dimensionally stable substrate with a relief-forming layer containing 40-90% thermoplastic elastomeric block copolymer, 0.1-20% ethylenically unsaturated monomers, 0.1-5% photoinitiator, and 1-40% plasticizer, specifically using ethylenically unsaturated monomers like tricyclodecanedimethanol diacrylate to enhance hardness and prevent anisotropy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional photopolymerizable flexographic printing elements are used, then the printing plate can be produced, but the hardness is insufficient and anisotropy issues occur
Solution Approach 1:
The patent modifies the chemical composition parameters of the photopolymerizable layer by incorporating specific ratios of thermoplastic elastomeric block copolymer (40-90 wt%), ethylenically unsaturated monomers (0.1-20 wt%), photoinitiator (0.1-5 wt%), and plasticizer (1-40 wt%). This parameter optimization enables the cured layer to achieve Shore A hardness of at least 66° while maintaining isotropic behavior, resolving the contradiction between hardness and compositional stability.
Solution Approach 2:
The patent creates a composite photopolymerizable system combining thermoplastic elastomeric block copolymer with ethylenically unsaturated monomers. This composite material structure allows the cured printing layer to simultaneously achieve high hardness and isotropic properties, as the specific combination of materials works synergistically to prevent anisotropy while enhancing strength.
2Strength
If the hardness of the printing plate is increased, then high-quality halftone printing is achieved, but the raw layer plasticity deteriorates
Solution Approach 1:
The patent optimizes the formulation parameters by carefully controlling the content of ethylenically unsaturated monomers (0.1-20 wt%) and plasticizer (1-40 wt%) in relation to the thermoplastic elastomeric block copolymer. This balanced parameter selection ensures that the uncured layer maintains adequate plasticity for manufacturing operations while the cured layer achieves the required hardness for high-quality halftone printing.
3Manufacturing precision
If conventional photopolymerizable layers are used, then the printing plate can be produced, but the tonal value range is limited and tonal value increase is high
Solution Approach 1:
The patent modifies the physical-chemical parameters of the photopolymerizable layer through optimized composition, which after curing produces a printing surface with improved optical and mechanical properties. This enables the finished printing plate to achieve a large tonal value range and small tonal value increase, meeting the requirements for high-quality halftone printing on plastic films or paper.
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 achieves flexographic printing plates with a Shore A hardness of at least 66°, reduced anisotropy, and improved raw layer plasticity, enabling high-quality printing with a large tonal value range and small tonal value increase, while maintaining isotropic properties.
Implementation Method 1
photopolymerizable, relief-forming layer containing, based in each case on the total amount of all components of the relief-forming layer, 40 to 90% by weight of a binder containing at least one thermoplastic elastomeric block copolymer, 0.1 to 20% by weight of ethylenically unsaturated monomers M, 0.1 to 5% by weight of photoinitiator
Data Source
AI summary
The invention relates to photopolymerizable flexographic printing elements which contain ethylenically unsaturated, alicyclic monomers and hard flexographic printing plates, in particular cylindrical continuous seamless flexographic printing plates, which can be produced therefrom.