Acrylic Epoxy Adhesive for OLED Delamination Resistance

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Solution Overview

Problem

Current adhesives for display devices, particularly organic light emitting diode (OLED) displays, face challenges in maintaining strong adhesive strength and internal agglomerative strength under conditions of consistent bending tension, which can lead to delamination.

Innovation Solution

An adhesive comprising an acrylic copolymer synthesized from a composition including a solution polymerizable acryl-based monomer, a vinyl-based monomer, a β-carboxylethyl acrylate monomer, and a compound with at least three epoxy functional groups, which improves adhesion and forms an effective cross-linking structure, enhancing peeling and initial adhesive strengths, and internal agglomerative strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional adhesives are used for OLED displays, then basic adhesive function is provided, but adhesive strength and internal agglomerative strength deteriorate under bending tension conditions

Engineering Contradiction:
Improveadhesive strengthVSAvoidresistance to delamination
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent uses a composite adhesive system combining acrylic copolymer with epoxy functional groups. The acrylic copolymer provides flexible adhesion while the epoxy groups form cross-linked networks, creating a composite material that maintains both high adhesive strength and resistance to delamination under bending tension.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical structure of the adhesive by incorporating β-carboxylethyl acrylate monomer with specific n values (1-12) and epoxy functional groups. These parameter changes in molecular structure enable the adhesive to maintain strength and prevent delamination under mechanical stress.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If adhesive composition is simplified, then manufacturing ease is improved, but adhesive performance and cross-linking structure deteriorate

Engineering Contradiction:
Improveadhesive composition complexityVSAvoidinternal agglomerative strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent introduces specific functional groups (epoxy groups with at least three epoxy functionalities) at local positions within the adhesive molecule. This local quality enhancement provides strong cross-linking sites without requiring complete structural complexity throughout the entire adhesive system, balancing manufacturability with performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The β-carboxylethyl acrylate monomer acts as an intermediary that bridges the acrylic copolymer chain and the epoxy functional groups. This intermediary structure enables effective cross-linking while maintaining a relatively simple overall composition that is easy to manufacture.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 adhesive exhibits peeling strengths greater than 4903 mN, initial adhesive strengths greater than 981 mN, and holding strengths greater than 2000 minutes, effectively preventing delamination even under consistent bending tension, thus ensuring the stability of the display device.

Implementation Method 1

an acrylic copolymer synthesized from a composition including a solution polymerizable acryl-based monomer, a vinyl-based monomer that is copolymerizable with the solution polymerizable acryl-based monomer, a β-carboxylethyl acrylate monomer, and a reaction initiator

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

a compound including at least three epoxy functional groups... forms an effective cross-linking structure, enhancing peeling and initial adhesive strengths, and internal agglomerative strength

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Data Source

PatentEP2687568B1Adhesive, adhesive tape, and display device
Publication Date: 2018.05.16 SAMSUNG DISPLAY CO LTD
  • EP2687568B1 patent drawingFigure 1~3
  • EP2687568B1 patent drawingFigure 4
  • EP2687568B1 patent drawingFigure 5A~5B

AI summary

An adhesive, comprising an acrylic copolymer comprising a solution polymerizable acryl-based monomer, a vinyl-based monomer that is copolymerizable with the solution polymerizable acryl-based monomer, and a β-carboxylethyl acrylate monomer; and a compound including at least three epoxy functional groups.