Crosslinked Polyurethane Adhesive Layer for Printing Form Attachment

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Solution Overview

Problem

Existing adhesive printing form attachment layers in flexographic printing face issues such as difficulty in removing residues, surface damage during plate replacement, and inconsistent adhesion, leading to print quality issues and reduced layer durability.

Innovation Solution

A novel adhesive printing form attachment layer with a crosslinked polyurethane-based polymeric compound on a substrate, providing high adhesion and strength while allowing easy removal and reuse, featuring a crosslinking gradient for optimal stickiness and cohesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a photopolymer layer without substrate is used to attach printing forms, then adhesion to printing cylinder is achieved, but the layer may come off during plate removal and surface damage occurs

Engineering Contradiction:
Improveadhesion forceVSAvoidlayer stability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

A substrate layer is introduced as an intermediary between the photopolymer adhesive layer and the printing cylinder. This substrate provides mechanical support and stability to the adhesive layer, preventing it from detaching during plate removal while maintaining strong adhesion to the printing cylinder surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention uses a composite structure combining a substrate layer with a photopolymer adhesive layer. The substrate layer (e.g., polyester, polypropylene, or polyethylene terephthalate) provides structural integrity, while the photopolymer layer provides adhesive properties, creating a material system that exhibits both strong adhesion and high stability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If strong adhesion is used to secure printing forms, then attachment reliability is improved, but residue removal becomes difficult and layer lifetime is reduced

Engineering Contradiction:
Improveattachment reliabilityVSAvoidresidue removal ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention controls the degree of crosslinking in the photopolymer adhesive layer by adjusting irradiation parameters (UV or electron beam radiation dose). By optimizing these parameters, the adhesive layer achieves sufficient crosslinking for strong attachment reliability while maintaining enough flexibility for easy residue removal, thus extending layer lifetime.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If double-sided adhesive tape is used for attachment, then ease of operation is improved, but alignment difficulty increases and printing performance deteriorates

Engineering Contradiction:
Improveattachment easeVSAvoidalignment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The adhesive attachment layer is designed as a single integrated layer that can be applied in one continuous piece, eliminating the need for multiple separate adhesive tape segments. This segmentation into a unified structure simplifies the attachment process and improves alignment precision.

Inventive Principle:
Principle #1Segmentation

4Strength

If sufficient crosslinking is achieved for layer integrity, then strength is improved, but stickiness is reduced

Engineering Contradiction:
Improvelayer strengthVSAvoidstickiness
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The invention creates a gradient in crosslinking density within the photopolymer adhesive layer. The region closer to the substrate has higher crosslinking density for strength and integrity, while the region closer to the printing plate interface has lower crosslinking density to maintain stickiness. This local variation in quality resolves the contradiction between strength and adhesion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of achieving complete and uniform crosslinking throughout the adhesive layer, the invention uses partial crosslinking with controlled irradiation doses. This partial action maintains sufficient layer integrity while preserving the adhesive properties needed for strong attachment, avoiding the excessive crosslinking that would eliminate stickiness.

Inventive Principle:
Principle #16Partial or excessive action

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 reliable and durable attachment of printing forms with improved print quality, easy residue removal, and extended layer lifetime by balancing adhesion and cohesion through a crosslinking gradient in the adhesive layer.

Implementation Method 1

the permanently sticky layer comprises a crosslinked structure obtained by crosslinking a crosslinkable composition

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS12006455B2Adhesive printing form attachment layer, method for its manufacture, and printing form attachment cylinder comprising the same
Publication Date: 2024.06.11 TESA SE

AI summary

The present invention relates to an adhesive printing form attachment layer comprising a support, and a permanently sticky layer suitable for receiving a printing form and fixing a printing form during a printing operation provided on the support, wherein the permanently sticky layer comprises a crosslinked structure obtained by crosslinking a crosslinkable composition comprising at least one polyurethane-based polymeric compound that has two or more crosslinkable groups, which are preferably ethylenically unsaturated groups, and two or more —NHC(O)O— linkages. A method of preparing the adhesive printing form attachment layer and of operating a printing machine using the adhesive printing form attachment layer are also disclosed.