Morpholine Acrylic Adhesive for Display ITO Corrosion

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Solution Overview

Problem

Existing adhesives for touchscreens and display members suffer from resistance variation, durability issues, and acid-induced corrosion of indium tin oxide (ITO) under high-temperature and high-humidity conditions, leading to separation, bubble formation, and light leakage.

Innovation Solution

A UV-curable adhesive composition incorporating a morpholine group-containing (meth)acrylic copolymer with a cross-linking agent, which includes a specific monomer mixture of C1 to C20 alkyl (meth)acrylates, alicyclic (meth)acrylates, hydroxyl group-containing monomers, and unsaturated morpholine, providing excellent durability and initial adhesive strength while suppressing resistance variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional adhesives are used for bonding display members, then initial adhesive strength is achieved, but resistance variation and durability deteriorate under high-temperature and high-humidity conditions

Engineering Contradiction:

ImprovedurabilityVSAvoidresistance variation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive by incorporating a morpholine group-containing (meth)acrylic copolymer with specific functional groups (carboxyl, hydroxyl, or amine groups). This compositional parameter change enables the adhesive to maintain stable electrical resistance and high durability under high-temperature and high-humidity conditions while preventing ITO corrosion.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite adhesive system combining the morpholine group-containing (meth)acrylic copolymer with a crosslinking agent. This composite material approach creates a network structure that simultaneously provides excellent adhesive strength, durability, and resistance to environmental degradation, resolving the contradiction between initial strength and long-term reliability.

Inventive Principle:

Principle #40Composite materials

2Strength

If existing adhesives are used, then adhesion is achieved, but ITO corrosion and separation occur under severe conditions

Engineering Contradiction:

Improveadhesive strengthVSAvoidITO corrosion

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potentially harmful interaction between adhesive and ITO into a beneficial protective relationship. The morpholine group-containing copolymer with specific functional groups (carboxyl, hydroxyl, or amine) forms a protective interface that prevents corrosive effects on ITO while maintaining strong adhesion, effectively turning a potential harm source into a protective mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The morpholine group-containing (meth)acrylic copolymer acts as an intermediary material between the adhesive and the ITO layer. This intermediary contains specific functional groups that interact favorably with both the ITO and the crosslinking agent, preventing direct corrosive interactions while maintaining strong bonding, thus resolving the contradiction between adhesion strength and ITO corrosion prevention.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If UV curable adhesive composition with morpholine group-containing copolymer is used, then durability and resistance stability are improved, but manufacturing complexity increases

Engineering Contradiction:

Improveresistance stabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional thermal curing or solvent-based adhesive systems with a UV-curable adhesive composition. This substitution allows for rapid curing through UV irradiation, reducing manufacturing cycle time and simplifying the overall process despite the specialized chemistry required. The UV curing mechanism provides precise control and eliminates the need for extended drying or heating processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 composition exhibits low resistance variation, high peel strength, and excellent durability, preventing ITO corrosion and separation, and allows for the formation of thick films without solvents, ensuring effective adhesion under severe conditions.

Implementation Method 1

A UV curable adhesive composition incorporating a morpholine group-containing (meth)acrylic copolymer with a cross-linking agent

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS9469528B2Adhesive composition, adhesive film including the same, method of preparing adhesive film, and display member using the same

Publication Date: 2016.10.18 CHEIL INDUSTRIES INC

AI summary

A display member includes a display panel, a first adhesive film on the display panel a transparent conductive layer on the first adhesive film, and a second adhesive film and a window on the second adhesive film. At least one of the first adhesive film and the second adhesive film includes a UV curable adhesive composition including a morpholine group-containing (meth)acrylic copolymer.