Photocurable Dendritic Polymer Resin for Flexible Display Adhesion
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Solution Overview
Problem
Existing adhesive resins for flexible and foldable display devices struggle to provide excellent coating properties across various shapes and types of display devices, necessitating improved adhesion and flexibility.
Innovation Solution
A resin composition comprising a dendritic polymer, a monofunctional (meth)acrylate monomer, a urethane (meth)acrylate oligomer, and a photoinitiator, which exhibits low viscosity before curing and high adhesion after curing, with a dendritic polymer content ranging from 0.5 wt% to 15 wt%, and a glass transition temperature between 25°C to 180°C, enabling low modulus and high peel force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesive resins are used, then basic adhesion is provided, but coating properties are poor and adhesion is insufficient for various display device shapes
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive resin by incorporating a dendritic polymer with specific molecular weight (1,000 to 50,000) and glass transition temperature (25°C to 180°C), along with specific ratios of monofunctional (meth)acrylate monomer (40-80 wt%) and urethane (meth)acrylate oligomer (20-60 wt%). This parameter optimization enables the resin to achieve both excellent coating properties across various display device shapes and reliable adhesion.
Solution Approach 2:
The patent creates a composite adhesive resin system combining multiple components: dendritic polymer, monofunctional (meth)acrylate monomer, and urethane (meth)acrylate oligomer. This composite formulation leverages the low viscosity of the dendritic polymer for excellent coating properties while the crosslinked network formed during curing provides high adhesion strength, resolving the contradiction between coating performance and adhesion reliability.
2Reliability
If adhesive resin is formulated for high adhesion, then bonding strength increases, but viscosity increases making coating difficult
Solution Approach 1:
The patent employs a photoinitiator system that enables preliminary action through UV curing. The resin composition is designed with low viscosity to facilitate easy coating and application first, then undergoes photo-curing to form a crosslinked network that provides high adhesion. This temporal separation of coating (low viscosity state) and bonding (crosslinked state) resolves the contradiction between ease of application and bonding strength.
Solution Approach 2:
The patent utilizes phase transition through photo-curing, where the resin transitions from a low-viscosity liquid state suitable for coating to a crosslinked gel/solid state providing high adhesion. The photopolymerization process triggers this phase transition, allowing the material to exhibit low viscosity during application and high adhesion after curing, effectively resolving the viscosity-adhesion contradiction.
3Reliability
If dendritic polymer content is increased to improve adhesion, then peel force increases, but viscosity increases before curing
Solution Approach 1:
The patent optimizes the dendritic polymer content parameter to a specific range (0.1 to 10 wt% of total resin composition) and controls its molecular weight (1,000 to 50,000) and glass transition temperature (25°C to 180°C). This parameter optimization ensures sufficient peel force (≥800 gf/25 mm) while maintaining low enough viscosity for easy coating, resolving the contradiction between adhesion strength and coating ease.
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 achieves excellent adhesion and flexibility, with a storage modulus of 1 MPa or less and a peel force of 800 gf/25 mm or greater, suitable for diverse display device configurations.
Implementation Method 1
at least one photoinitiator including a radical polymerization initiator
Data Source
AI summary
A resin composition includes at least one monofunctional (meth)acrylate monomer, a urethane (meth)acrylate oligomer having a weight average molecular weight of approximately (about) 5,000 to approximately (about) 100,000, a dendritic polymer, and at least one photoinitiator including a radical polymerization initiator. The resin composition may exhibit low-viscosity properties before being cured, and may exhibit a storage modulus of approximately (about) 1 MPa or less at a frequency of approximately (about) 1 Hz and a temperature of approximately (about) −20° C., a 180° peel force of approximately (about) 800 gf/25 mm or greater with respect to at least one of a glass substrate or a polymer substrate at a temperature of approximately (about) 25° C., and a glass transition temperature of 0° C. or less, after being cured.