Urethane Acrylate Adhesive for Flexible Displays
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Solution Overview
Problem
Flexible display devices require adhesive members with excellent coating properties and high adhesion strength to ensure reliable operation when folded or bent, as existing adhesive resins often fail to provide sufficient durability and reliability in these conditions.
Innovation Solution
A resin composition comprising a (meth)acrylic monomer with at least one (meth)acryloyl group, a urethane acrylate oligomer with a weight average molecular weight of 27,000 to 50,000, and a photoinitiator, which after UV curing, exhibits a low modulus of elasticity and high adhesion characteristics, thereby forming an effective adhesive member for flexible display devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesive resins are used in flexible display devices, then the device structure can be simple, but the adhesion strength and operational reliability deteriorate when folded or bent
Solution Approach 1:
The patent modifies the molecular weight parameter of the urethane acrylate oligomer to a specific range (27,000 to 50,000), which fundamentally changes the adhesive's mechanical properties. This parameter optimization enables the adhesive to simultaneously achieve low modulus of elasticity (1.0×10³ to 1.0×10⁶ Pa) for flexibility and high adhesion strength (15 N/inch or more) for reliability, resolving the contradiction between strength and flexibility in folded display devices
Solution Approach 2:
The patent creates a composite resin composition by combining three distinct components: (meth)acrylic monomer, urethane acrylate oligomer with specific molecular weight, and photoinitiator. This composite formulation synergistically integrates the low viscosity and coating properties of the monomer with the mechanical flexibility and adhesion of the oligomer, achieving both high adhesion strength and operational reliability in folded conditions
2Strength
If adhesive resin with high adhesion strength is used, then bonding reliability improves, but the modulus of elasticity increases making the adhesive too rigid for flexible devices
Solution Approach 1:
The patent precisely controls the molecular weight parameter of the urethane acrylate oligomer (27,000 to 50,000) to optimize the balance between strength and flexibility. This specific molecular weight range produces an adhesive with modulus of elasticity in the range of 1.0×10³ to 1.0×10⁶ Pa, which is low enough to maintain flexibility during folding while still achieving adhesion strength of 15 N/inch or more, thus resolving the contradiction between strength and elastic modulus
3Ease of operation
If low viscosity resin is used for good coating properties, then coating performance improves, but adhesion strength after curing may be insufficient
Solution Approach 1:
The patent formulates a composite resin system where the (meth)acrylic monomer provides low viscosity (10 to 50 mPa·s) for excellent coating properties, while the urethane acrylate oligomer with molecular weight 27,000 to 50,000 ensures high adhesion strength (15 N/inch or more) after curing. The synergistic combination of these components resolves the contradiction between ease of coating and adhesion strength
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 resin composition and resulting adhesive member demonstrate excellent operational reliability when folding due to their low modulus of elasticity and high adhesive strength, preventing peeling or gaps in bent areas and ensuring consistent performance in flexible display devices.
Implementation Method 1
a resin composition for a display device includes: a (meth)acrylic monomer having at least one (meth)acryloyl group; a urethane acrylate oligomer having a weight average molecular weight of about 27,000 to about 50,000; and at least one photoinitiator
Data Source
AI summary
A resin composition for a display device includes: a (meth)acrylic monomer having at least one (meth) acryloyl group; a urethane acrylate oligomer having a weight average molecular weight of about 27,000 to about 50,000; and at least one photoinitiator.