Foldable Display Adhesive Composition for Reliable Touch
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Solution Overview
Problem
Conventional adhesive layers for foldable displays face challenges in maintaining reliability, preventing lifting and peeling, and achieving high permittivity to support sensitive touch responses, especially when folded, due to limitations in existing materials and formulations.
Innovation Solution
An adhesive composition comprising a (meth)acrylate resin with a glass transition temperature of −70° C. or lower, an epoxy crosslinking agent, a metal salt, and acetylacetone, which enhances curing stability and internal ionic conductivity, thereby improving the adhesive and folding properties while increasing permittivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesive materials are used in foldable displays, then the display can be folded, but lifting and peeling occur due to insufficient adhesion and reliability
Solution Approach 1:
The patent uses a composite adhesive system comprising a (meth)acrylate resin base polymer combined with epoxy crosslinking agent, metal salt, and acetylacetone. This multi-component composition creates a composite material that synergistically provides both adhesion and anti-lifting properties, resolving the contradiction between reliability and harmful lifting/peeling effects
Solution Approach 2:
The patent modifies the adhesive properties by controlling the glass transition temperature of the (meth)acrylate resin at −70° C. or lower, and by optimizing the storage modulus within specific ranges (1×10^5 ≤ G1′ ≤ 1×10^6 Pa at −30° C. and 1×10^4 ≤ G2′ ≤ 1×10^5 Pa at 60° C.). These parameter changes enable the adhesive to maintain reliability while preventing lifting and peeling
2Measurement precision
If adhesive layer with high permittivity is used to support sensitive touch response, then touch resolution improves, but adhesive stability and folding reliability may be compromised
Solution Approach 1:
The patent achieves high permittivity by incorporating metal salt and acetylacetone into the adhesive composition, which increases internal ionic conductivity. Simultaneously, the adhesive stability is maintained by controlling the storage modulus within specific ranges and using a (meth)acrylate resin with Tg of −70° C. or lower, thus resolving the contradiction between touch resolution and adhesive stability
Solution Approach 2:
The composite adhesive system combines (meth)acrylate resin, epoxy crosslinking agent, metal salt, and acetylacetone to create a material that simultaneously provides high permittivity for sensitive touch response and sufficient stability for reliable folding performance
3Adaptability or versatility
If the adhesive layer is made softer to enable folding without damage, then folding characteristics improve, but adhesion strength and structural support may decrease
Solution Approach 1:
The patent optimizes the balance between softness and strength by controlling the storage modulus within specific temperature-dependent ranges and using a (meth)acrylate resin with Tg of −70° C. or lower. This enables the adhesive to be soft enough for folding while maintaining sufficient adhesion strength
Solution Approach 2:
The adhesive exhibits dynamic mechanical properties with different storage modulus values at different temperatures (1×10^5 ≤ G1′ ≤ 1×10^6 Pa at −30° C. and 1×10^4 ≤ G2′ ≤ 1×10^5 Pa at 60° C.), allowing it to be flexible during folding while maintaining structural support during operation
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 maintains adhesive and folding stability, enhances permittivity, and enables high-resolution, quick-response touch capabilities in TOE-type structures without causing damage to foldable displays.
Implementation Method 1
acetylacetone having a greater interaction with metal ions than epoxy, thereby preventing the decrease in the extent of curing of the adhesive layer and improving storage stability
Implementation Method 2
The adhesive layer according to another embodiment of the present application exhibits increased internal ionic conductivity and thus increased permittivity by adding a metal salt to an adhesive layer having a reduced modulus
Implementation Method 3
a (meth)acrylate resin having a glass transition temperature (Tg) of −70° C. or lower
Data Source
AI summary
Provided are an adhesive composition, an adhesive layer comprising the same and a foldable display comprising the same.