Flexographic Printing Plate Barrier Layer for Oxygen-Free UVA Curing
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Solution Overview
Problem
Existing flexographic printing plates face issues with oxygen interference during exposure, leading to insufficient polymerization of relief elements, rounded corners, and difficulty in reproducing fine details, while integrated barrier layers often cause defects and adhesion problems between layers.
Innovation Solution
A flexographic printing plate composition with a transparent, oxygen-blocking barrier layer containing an oligomeric or polymeric basic adhesive component, ensuring adhesion and solubility in organic solvents, integrated with a laser-ablatable mask layer and cover film, allowing for precise reproduction of surface topography and improved ink transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer is integrated into the flexographic printing element to protect from oxygen during exposure, then polymerization completeness is improved, but layer adhesion defects occur
Solution Approach 1:
The patent applies composite materials by creating a multilayer structure consisting of a carrier film, photopolymerizable layer, barrier layer, laser-ablatable mask layer, and cover film. Each layer is designed with specific properties and the interfaces are optimized for adhesion. The barrier layer is integrated during manufacturing with controlled adhesion promoters and surface treatments to prevent delamination while maintaining oxygen barrier function throughout polymerization.
Solution Approach 2:
The patent applies local quality by giving different regions and layers specific functions: the barrier layer provides oxygen protection in areas requiring complete polymerization, while laser-ablatable regions allow selective removal of mask material. The adhesion properties are locally optimized at layer interfaces using adhesion promoters and surface treatments only where needed, rather than uniformly across all layers.
2Reliability
If high-power UVA light is used to overcome oxygen influence, then polymerization completeness is improved, but equipment cost and complexity increase
Solution Approach 1:
The patent converts the harmful effect of oxygen into a beneficial design feature by incorporating a barrier layer that selectively blocks oxygen while allowing UVA light transmission. This transforms the oxygen exclusion problem from requiring high-power equipment into a passive material-based solution using transparent barrier materials that naturally prevent oxygen diffusion during exposure.
Solution Approach 2:
The barrier layer acts as an intermediary between the photopolymerizable layer and atmospheric oxygen. This intermediate layer selectively transmits UVA radiation needed for polymerization while blocking oxygen molecules, thereby mediating the interaction between light and oxygen without requiring modification of the exposure equipment.
3Reliability
If exposure is carried out under protective gas or vacuum to eliminate oxygen, then polymerization completeness is improved, but process complexity and equipment requirements increase
Solution Approach 1:
The patent extracts the oxygen exclusion function from the exposure process environment and incorporates it directly into the printing element structure itself. Instead of removing oxygen from the exposure atmosphere using vacuum or protective gas systems, the barrier layer is integrated into the element to physically block oxygen access to the photopolymerizable layer during exposure.
4Object-affected harmful factors
If the barrier layer is made opaque to block oxygen, then oxygen protection is improved, but UVA light transmission for polymerization is reduced
Solution Approach 1:
The patent applies parameter changes by selecting barrier materials with specific optical and barrier properties. The barrier layer is designed with controlled thickness, oxygen permeability, and UVA transmission characteristics. Materials are chosen that provide sufficient oxygen barrier function while maintaining high transparency in the UVA range (300-400 nm), optimizing the balance between oxygen protection and light transmission for polymerization.
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 ensures high-resolution printing with improved ink transfer and adhesion, while maintaining ease of processing and avoiding defects, using commercially available equipment and solvents, and achieving consistent print quality.
Implementation Method 1
an organically soluble barrier layer for oxygen
Implementation Method 2
The photopolymerizable layer polymerizes in the areas no longer covered by the mask, while no polymerization occurs in the covered areas
Implementation Method 3
the layer is degraded at the points where it is struck by the laser beam, exposing the photopolymerizable layer beneath
Data Source
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AI summary
The invention relates to a method for producing a flexographic printing form from a digitally imageable, photopolymerizable flexographic printing element comprising, arranged one above the other in the aforementioned order, at least one dimensionally stable carrier (A), at least one photopolymerizable, relief-forming layer (B), a UVA-light transparent, oxygen-blocking barrier layer (C), a laser-ablatable mask layer (D), and a peelable cover film (E), wherein the method comprises at least the steps (i) peeling off the cover film (E), (ii) inscribing a mask into the laser-ablatable mask layer (D) using an IR laser, (iii) exposing the imaged flexographic printing element with UVA light through the formed mask, (iv) removing the residues of the laser-ablatable mask layer (D), the barrier layer (C), and the unpolymerized portions of the relief-forming layer (B).and (v) optionally includes post-exposure of the dried flexographic printing plate with UVA and/or UVC light, wherein layers (B), (C) and (D) are soluble or dispersible in an organic solvent, and the barrier layer (C) contains at least an oxygen-blocking binder and an oligomeric or polymeric basic adhesive component, and that the at least partial removal according to step (iv) is carried out by heating and removing the unexposed areas using a developing material.