Foldable Display Adhesive Composition for Extreme Temperature Reliability
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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., due to inadequate rheological properties and stress distribution.
Innovation Solution
An adhesive composition comprising a polymer with alkyl (meth)acrylate and a monomer having a crosslinkable functional group, combined with a crosslinking agent, which provides a specific range of adhesive strength, storage modulus, and stress drop to ensure durability and reliability across various temperatures, including −20° C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing adhesive compositions are used to satisfy room temperature and high temperature reliability conditions, then adhesive strength and stability are maintained at normal operating temperatures, but delamination and panel breakage occur during dynamic folding tests at extreme low temperatures (−20° C.)
Solution Approach 1:
The patent modifies the rheological parameters of the adhesive by controlling storage modulus (G') and loss modulus (G'') ratios, and by adjusting the glass transition temperature (Tg) to be below −50° C. These parameter changes enable the adhesive to maintain flexibility and adhesion at extreme low temperatures while preventing delamination during folding tests
Solution Approach 2:
The patent uses a composite adhesive system combining polymer base resins with specific rubber modifiers and functional additives. This composite structure provides both the required adhesion at room temperature and the flexibility needed at extreme low temperatures, resolving the contradiction between strength and reliability across temperature ranges
2Strength
If adhesive stiffness is increased to prevent delamination, then bonding strength improves, but stress concentration and panel breakage increase during folding at low temperatures
Solution Approach 1:
The patent incorporates rubber modifiers and plasticizers in advance to cushion the adhesive against stress concentration during folding. These additives create a more compliant adhesive matrix that absorbs mechanical stress before it can concentrate and cause panel breakage, while still maintaining adequate bonding strength
3Reliability
If adhesive composition is optimized for room temperature performance, then adhesion properties are satisfied, but folding reliability under extreme temperature conditions deteriorates
Solution Approach 1:
The patent develops a universal adhesive composition that functions effectively across a wide temperature range (−40° C. to 60° C.). The formulation includes multiple functional components that collectively provide both room temperature adhesion and extreme temperature reliability, making the adhesive adaptable to all operating conditions without requiring temperature-specific variants
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 no delamination or breakage during folding and recovery at −20° C., maintaining excellent adhesion and durability while satisfying the reliability conditions of existing adhesive compositions at room and high temperatures.
Implementation Method 1
a polymer comprising an alkyl (meth)acrylate and a monomer having a crosslinkable functional group, and a crosslinking agent
Implementation Method 2
a rheology behavior condition of the adhesive needs to be satisfied, and among rheological properties of the adhesive, the storage modulus value needs to be greater than or equal to 104 Pa and less than or equal 106 Pa
Data Source
AI summary
An adhesive composition for a foldable display comprising a polymer comprising an alkyl (meth)acrylate and a monomer having a crosslinkable functional group; and a crosslinking agent is provided.