Radiation-Curable Polyvinyl Acetate Mixture for Relief Structures
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Solution Overview
Problem
Radiation-curable relief structures produced from existing mixtures suffer from curling, low elongation at break, and low elasticity, making them difficult to mount and prone to cracking, especially when attempting to image high halftone tonal values effectively.
Innovation Solution
A radiation-curable mixture comprising functionalized, part-hydrolyzed polyvinyl acetate with a low fraction of vinyl acrylate units, combined with a photopolymerization initiator and ethylenically unsaturated compounds, and optionally adjuvants like hydrogen bond-forming additives, which reduces curling and enhances mechanical properties while maintaining exposure and washout times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If functionalized, part-hydrolyzed polyvinyl acetate with high degree of functionalization is used, then adhesion and stability are improved, but curling increases and mechanical properties deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the functionalization degree (0.5-5 mol %) and hydrolysis degree (50-90 mol %) of the polyvinyl acetate binder. This optimization balances the adhesion/stability benefits of functionalization against the curling and mechanical property deterioration caused by excessive functionalization.
Solution Approach 2:
The patent uses composite materials by combining functionalized, part-hydrolyzed polyvinyl acetate with specific photopolymerization initiators and ethylenically unsaturated compounds. This composite approach allows the binder to provide adhesion and stability while the additional components control curling and enhance mechanical properties.
2Reliability
If functionalized, part-hydrolyzed polyvinyl acetate with high degree of functionalization is used, then adhesion is improved, but elongation at break and elasticity decrease
Solution Approach 1:
The patent optimizes the functionalization degree to a low range (0.5-5 mol %) rather than using high functionalization. This parameter change maintains adequate adhesion while preserving elongation at break and elasticity by avoiding excessive crosslinking and rigidity.
Solution Approach 2:
The patent applies local quality by creating regions with different functional group concentrations through controlled partial hydrolysis and functionalization. This allows local adhesion promotion at interfaces while maintaining overall material flexibility and elasticity in the bulk.
3Ease of manufacture
If conventional radiation-curable mixtures are used, then production is simplified, but exposure times increase and washout times increase
Solution Approach 1:
The patent changes the chemical composition parameters of the radiation-curable mixture by using specifically functionalized polyvinyl acetate with controlled low functionalization degrees. This composition optimization improves radiation sensitivity and crosslinking efficiency, reducing exposure times while maintaining production simplicity.
4Ease of manufacture
If conventional radiation-curable mixtures are used, then production is simplified, but washout times increase
Solution Approach 1:
The patent optimizes the hydrolysis degree (50-90 mol %) and functionalization degree (0.5-5 mol %) parameters of the polyvinyl acetate binder. This creates a composition with balanced water solubility and crosslinking density, enabling faster washout of unexposed regions while keeping the production process simple.
5Manufacturing precision
If relief structures with high halftone tonal values are imaged, then image quality is improved, but cracking increases due to low elasticity
Solution Approach 1:
The patent changes the binder composition parameters to achieve low functionalization (0.5-5 mol %) and controlled hydrolysis (50-90 mol %). This creates relief structures with optimized elasticity that can accommodate high halftone tonal values without cracking, while maintaining good image quality.
Solution Approach 2:
The patent uses a composite radiation-curable mixture containing functionalized polyvinyl acetate combined with photopolymerization initiators and ethylenically unsaturated compounds. This composite formulation provides the elasticity needed to prevent cracking in high halftone areas while maintaining sufficient crosslinking for image fidelity.
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 significantly reduces curling and improves the mechanical properties of the relief structures, allowing for better mounting and imaging of high halftone tonal values with reduced cracking and increased elasticity.
Implementation Method 1
at least one photopolymerization initiator, one or more ethylenically unsaturated, photopolymerizable, low molecular mass compounds
Data Source
AI summary
The invention relates to a radiation-curable mixture for generating relief structures, comprisinga) at least one functionalized, part-hydrolyzed polyvinyl acetate comprising (i) vinyl alcohol units, (ii) vinyl acetate units, and (iii) vinyl acrylate units, where the vinyl acrylate units, which can be substituted, have the general structurewhere R is hydrogen or a linear or branched aliphatic or heteroaliphatic radical having 1 to 12 carbon atoms, or a cycloaliphatic, heterocyclic or aromatic radical having 3 to 12 carbon atoms, as component A,b) at least one initiator as component B,c) at least one ethylenically unsaturated compound different from component A, as component C,d) one or more adjuvants as component D,wherein the amount of vinyl acrylate units (iii) in the functionalized, part-hydrolyzed polyvinyl acetate a), based on all the units (i), (ii), and (iii), is 0.1 to <3 mol %, and component D comprises an additive capable of hydrogen bonding, in an amount of 0.001 to 30 wt %, based on the sum of components A to D.