Acrylic Adhesive Composition for Foldable Display Bonding Stability
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Solution Overview
Problem
Existing adhesive compositions fail to provide adequate adhesion, durability, and flexibility under harsh conditions and repetitive bending/folding, especially in flexible displays and devices with integrated touch panels and antennas.
Innovation Solution
An adhesive composition comprising an acrylic copolymer with specific monomer blends, an organometallic compound, and an isocyanate compound, which enhances elasticity, adhesion, and recovery ratio, ensuring stable adhesion and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesive compositions are used, then basic adhesion is provided, but adhesion and durability under harsh conditions and repetitive bending/folding are insufficient
Solution Approach 1:
The patent uses a composite adhesive system comprising acrylic copolymer, organometallic compound, and isocyanate compound. The acrylic copolymer provides base adhesion, the organometallic compound (e.g., titanium, zirconium, aluminum, zinc, iron, or tin compounds) enhances bonding strength, and the isocyanate compound creates cross-linked networks for durability. This composite approach achieves both reliable adhesion under harsh conditions and flexibility for repetitive bending/folding.
Solution Approach 2:
The patent specifies precise compositional parameters: acrylic copolymer with 80-97 wt% alkyl (meth)acrylate monomer (8-18 carbon atoms), 3-20 wt% hydroxyl group-containing polar monomer, and 3 wt% or less acid group-containing polar monomer. The organometallic compound content is controlled at 0.1-2.0 parts by weight per 100 parts acrylic copolymer, and isocyanate compound at 0.001-0.5 parts by weight per 100 parts acrylic copolymer. These optimized parameters achieve the desired balance of adhesion durability and flexibility.
2Strength
If adhesive composition is formulated for high adhesion strength, then bonding strength is improved, but elasticity and recovery ratio are reduced
Solution Approach 1:
The patent optimizes the chemical composition parameters to achieve both strength and elasticity. The acrylic copolymer with specific monomer ratios provides a balanced molecular structure, the organometallic compound enhances cross-linking density for strength, and the isocyanate compound creates a three-dimensional network that maintains elasticity. The specific weight percentages and parts by weight ratios are tuned to achieve 80% or more recovery ratio while maintaining high adhesion strength.
Solution Approach 2:
The isocyanate compound acts as an intermediary that reacts with hydroxyl groups in the acrylic copolymer to form cross-linked urethane bonds. This intermediary reaction creates a three-dimensional network structure that simultaneously provides mechanical strength and elastic recovery capability, resolving the contradiction between strength and elasticity.
3Adaptability or versatility
If adhesive composition is designed for flexibility in flexible displays, then bending flexibility is improved, but adhesion stability under external impact is reduced
Solution Approach 1:
The patent employs a composite adhesive system where the acrylic copolymer provides flexibility through its molecular structure, the organometallic compound (such as titanium or zirconium compounds) enhances adhesion stability through strong bonding, and the isocyanate compound creates a cross-linked network that maintains both flexibility and adhesion stability under external impact conditions.
Solution Approach 2:
The patent specifies precise compositional parameters including 80-97 wt% alkyl (meth)acrylate monomer with 8-18 carbon atoms for flexibility, 3-20 wt% hydroxyl group-containing polar monomer for bonding, and controlled amounts of organometallic (0.1-2.0 parts) and isocyanate (0.001-0.5 parts) compounds. These parameter optimizations enable the adhesive to maintain both flexibility for flexible displays and adhesion stability under external impact.
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 achieves improved adhesion, durability, and flexibility, maintaining stability through repetitive bending and folding, with a recovery ratio of 80% or more, and a low elastic modulus at low temperatures.
Implementation Method 1
an adhesive composition, including: an acrylic copolymer including a polymer of a monomer blend that includes 80 to 97 wt % of an alkyl (meth)acrylate monomer having an alkyl group having 8 or more carbon atoms, 3 to 20 wt % of a hydroxyl group-containing polar monomer, and 3 wt % or less of an acid group-containing polar monomer; an organometallic compound; and an isocyanate compound
Implementation Method 2
the organometallic compound includes a metal chelate compound including at least one metal atom of titanium, zirconium, aluminum, zinc, iron and tin
Data Source
AI summary
An adhesive composition includes an acryl-based copolymer, an organometallic compound and an isocyanate compound. The acryl-based copolymer may include a polymer of a monomer blend comprising 80 to 97 wt % of an alkyl(meth)acrylate monomer having an alkyl group having a carbon number of 8 or greater, and 3 to 20 wt % of a polar monomer, and 3 wt % or less of an acid group-containing polar monomer. This adhesive sheet including an adhesive layer can provide excellent recovery rate, adhesive force, and folding properties.