Optical Display Adhesive Sheet for Strong Peel and Clean Rework

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Solution Overview

Problem

Existing adhesive sheets for optical display devices face issues with poor peel strength and reworkability, leading to residue and foreign matter upon removal, which affects the appearance and attachment of new sheets.

Innovation Solution

An adhesive sheet composed of a hydroxyl group-containing (meth)acrylic copolymer, photocurable crosslinking agent, and thermosetting crosslinking agent, including isocyanate type crosslinking agents, with specific formulations to achieve peel strengths of 600 gf/in or more and surface energies of 70 mN/m or more, ensuring good residue characteristics and storage stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the adhesive sheet is attached to the display panel to protect components, then the peel strength is improved, but residue and foreign matter remain on the adherend upon removal

Engineering Contradiction:
Improvepeel strengthVSAvoidresidue
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent adjusts the surface energy parameter of the adhesive layer to a specific range (60-80 mN/m) to optimize the balance between adhesion strength and removability. This parameter change enables the adhesive to maintain strong bonding while allowing clean removal without residue, directly resolving the contradiction between peel strength and residue generation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite adhesive composition containing multiple components: hydroxyl group-containing (meth)acrylic copolymer as the base resin, photocurable crosslinking agents for UV curing, and thermosetting crosslinking agents for thermal curing. This composite formulation achieves both strong adhesion and clean removability by combining the beneficial properties of different materials

Inventive Principle:
Principle #40Composite materials

2Ease of repair

If the adhesive sheet is removed from the display panel, then the reworkability is improved, but residue and foreign matter obstruct attachment of new adhesive sheet

Engineering Contradiction:
ImprovereworkabilityVSAvoidforeign matter
Core Design Contradiction:
Ease of repairVSObject-generated harmful factors

Solution Approach 1:

By precisely controlling the surface energy within 60-80 mN/m and adjusting the composition ratios of crosslinking agents, the adhesive achieves optimal removability. This allows complete removal without residue or foreign matter, enabling clean reworkability and subsequent attachment of new adhesive sheets without obstruction

Inventive Principle:
Principle #35Parameter changes

3Strength

If the adhesive composition includes multiple crosslinking agents to improve peel strength, then the storage stability deteriorates

Engineering Contradiction:
Improvepeel strengthVSAvoidstorage stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent incorporates photoinitiators that remain dormant during storage and only activate upon UV irradiation. This preliminary preparation allows the adhesive composition to maintain storage stability (low viscosity change, no premature curing) while still achieving strong crosslinked adhesion when properly cured, resolving the contradiction between strength and stability

Inventive Principle:
Principle #10Preliminary 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 adhesive sheet provides excellent peel strength, reworkability, and residue-free removal, maintaining the integrity of the adherend for subsequent attachments, while ensuring storage stability.

Implementation Method 1

a photoinitiator, a photocurable crosslinking agent

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

a thermosetting crosslinking agent including an isocyanate type crosslinking agent and a carboxyl group-containing (meth)acrylate

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 3

a hydroxyl group-containing (meth)acrylic copolymer

Methodology Applied
Scientific EffectHydrogen bonding:

Implementation Method 4

a hydroxyl group-containing (meth)acrylic copolymer

Methodology Applied
Scientific EffectVan der Waals force: Van der Waals Force

Implementation Method 5

a surface energy of about 70 mN/m or more at 25° C.

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS12480026B2Adhesive sheet, adhesive composition therefor, optical member comprising same, and optical display device comprising same
Publication Date: 2025.11.25 SAMSUNG SDI CO LTD

AI summary

Provided are an adhesive sheet, an adhesive composition therefor, an optical member comprising same, and an optical display device comprising same, wherein the adhesive sheet comprises an adhesive layer formed of an adhesive composition containing a hydroxyl group-containing (meth)acrylic copolymer, a photo-initiator, a photo-curable crosslinking agent, and a heat-curable crosslinking agent; the heat-curable crosslinking agent contains an isocyanate-type crosslinking agent and carboxyl group-containing (meth)acrylate; the adhesive layer has a peeling strength of about 600 gf/in or more relative to a glass substrate at 25° C. and has a surface energy of about 70 mN/m or more at 25° C.