Adhesive Composition for Foldable Displays at Low Temperatures
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Solution Overview
Problem
Existing adhesive compositions for foldable displays fail to maintain reliability and prevent delamination and breakage during dynamic folding tests, especially at extreme temperatures like −20° C.
Innovation Solution
An adhesive composition comprising a polymer with an alkyl (meth)acrylate and a monomer having a crosslinkable functional group, along with a crosslinking agent, which provides an adhesive strength of 500-5,000 gf/in with a storage modulus of 50,000-250,000 Pa and strain recovery of 70-90% at −20° C., ensuring durability and resistance to delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing adhesive compositions are used to satisfy folding reliability conditions at room temperature and high temperature, then adhesive properties are maintained, but delamination and panel breakage occur during dynamic folding tests at -20°C
Solution Approach 1:
The patent modifies the adhesive composition by incorporating specific polymers (acrylic polymer, vinyl polymer, or their copolymers) with controlled molecular weights and compositions, along with crosslinking agents, to achieve optimal storage modulus (50,000-250,000 Pa) and adhesive strength (500-5,000 gf/in) that prevent delamination at -20°C while maintaining folding reliability
Solution Approach 2:
The patent creates a composite adhesive system combining multiple polymer types (acrylic and vinyl polymers) with crosslinking agents to achieve synergistic effects that simultaneously provide low-temperature flexibility and high-temperature stability, preventing both delamination and breakage across the temperature range
2Strength
If adhesive strength is increased to prevent delamination, then bonding reliability improves, but flexibility and strain recovery decrease causing breakage during folding
Solution Approach 1:
The patent optimizes the balance between adhesive strength and flexibility by controlling the storage modulus within 50,000-250,000 Pa and adhesive strength within 500-5,000 gf/in through selective polymer combinations and crosslinking densities, enabling the adhesive to maintain both strong bonding and sufficient elasticity for strain recovery during repeated folding
Solution Approach 2:
The patent designs the adhesive composition to dynamically adapt its mechanical properties during folding cycles, allowing the material to exhibit appropriate stiffness during bonding while maintaining flexibility during deformation, achieving both strong adhesion and damage-free folding through controlled viscoelastic behavior
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 ensures reliable adhesion and resistance to delamination and breakage at extreme temperatures, maintaining excellent durability and cohesive strength during repeated folding and unfolding.
Implementation Method 1
comprising a polymer comprising an alkyl (meth)acrylate and a monomer having a crosslinkable functional group, and a crosslinking agent
Data Source
AI summary
An adhesive composition for a foldable display including a polymer comprising an alkyl (meth)acrylate and a monomer having a crosslinkable functional group; and a crosslinking agent.