Elastomeric Cap Layer Printing Form Precursor

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Solution Overview

Problem

Current flexographic printing forms face challenges in achieving uniform, dense ink transfer to substrates, particularly in large areas, leading to print defects like mottle and graininess, and struggle to maintain fine details and high resolution due to oxygen inhibition during digital workflow exposure.

Innovation Solution

A printing form precursor with a photopolymerizable layer and an elastomeric cap layer containing particulate, such as polyamide, polymethylmethacrylate, feldspar, or glass particles, which forms an in-situ mask using laser radiation, allowing for improved ink transfer and maintaining fine features without detrimental impact on dot gain or image resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If digital workflow exposure is used to form printing forms, then productivity is improved through direct imaging, but manufacturing precision deteriorates due to oxygen inhibition causing loss of fine details and resolution

Engineering Contradiction:

ImproveproductivityVSAvoidmanufacturing precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The elastomeric cap layer creates an oxygen barrier that establishes an inert environment during exposure, preventing oxygen inhibition and enabling high-resolution imaging while maintaining digital workflow productivity

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Ease of manufacture

If conventional photopolymerizable layers are used, then ease of manufacture is maintained, but reliability deteriorates due to poor ink transfer uniformity and print defects

Engineering Contradiction:

Improveease of manufactureVSAvoidreliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The printing form precursor uses a composite structure with a photopolymerizable layer and an elastomeric cap layer containing particulate, combining the ease of photopolymerization with improved ink transfer reliability and print quality

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If the elastomeric cap layer contains particulate with mismatched index of refraction, then ease of manufacture is improved, but manufacturing precision deteriorates due to light scattering affecting resolution

Engineering Contradiction:

Improveease of manufactureVSAvoidmanufacturing precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The particulate in the elastomeric cap layer is selected to have an index of refraction within ±0.05 of the elastomeric binder, optimizing light transmission parameters to prevent scattering while maintaining ease of manufacture

Inventive Principle:

Principle #35Parameter changes

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 enhances solid ink density and uniformity, maintains fine text and highlight dot quality, and resists wear and deformation, resulting in improved print quality with increased solid ink density and reduced dot gain.

Implementation Method 1

The precursor is exposed to actinic radiation, such as ultraviolet (UV) radiation, to selectively cure the photopolymerizable layer. The actinic radiation enters the photosensitive element through the transparent (or clear) areas and is blocked from entering the photopolymerizable layer by the black or opaque areas of the transparency or in-situ mask.

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

The elastomeric composition is or becomes sensitive to the actinic radiation... The actinic radiation enters the photosensitive element through the transparent (or clear) areas and is blocked from entering the photopolymerizable layer by the black or opaque areas of the transparency or in-situ mask.

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 3

forming an in-situ mask by imagewise exposing the actinic radiation opaque layer with laser radiation

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP2831672B1Printing form precursor having elastomeric cap layer and a method of preparing a printing form from the precursor

Publication Date: 2017.09.27 EI DU PONT DE NEMOURS & CO

AI summary

The invention pertains to a printing form precursor, a method of preparing a printing form from the precursor, and a process of preparing the precursor. The printing form precursor includes a photopolymerizable layer, an elastomeric layer having at least an elastomeric binder and particulate, and an actinic radiation opaque material on, adjacent, or disposed above the elastomeric layer opposite the photopolymerizable layer. The particulate is selected from specific material particles having an average diameter from 1 to 10 micron and a refractive index that is within 0.04 units of an index of refraction of the composition forming the elastomeric layer.