Resin Composition for Flexible Displays
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Solution Overview
Problem
Conventional resin materials, such as urethane and silicone resins, exhibit high tensile elongation and recoverability but lack stress relaxation properties, leading to residual stress and potential detachment or breakage in flexible display devices due to poor stress relaxation and limited temperature range.
Innovation Solution
A resin composition that undergoes elastic deformation with low residual strain rate and exhibits high stress relaxation properties, characterized by a stress relaxation rate of 20 to 95% and residual strain rate of 0 to 3%, achieved through a combination of polyrotaxane, thermosetting resin, and curing agent, specifically epoxy resin, which allows for excellent recoverability and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If urethane resins or silicone resins are used to achieve high tensile elongation and recoverability, then flexibility and shape recovery are improved, but stress relaxation properties deteriorate leading to residual stress accumulation
Solution Approach 1:
The patent combines polyrotaxane (providing elasticity and stress relaxation) with thermosetting resin (providing strength and shape recovery) to create a composite material that achieves both high tensile elongation/recoverability and excellent stress relaxation properties, resolving the contradiction between flexibility and stress relaxation
Solution Approach 2:
The patent modifies the molecular structure parameters of polyrotaxane by controlling the ratio of axial polyethylene glycol to cyclic α-cyclodextrin (1:0.01 to 1:10) and the degree of crosslinking, thereby adjusting the stress relaxation rate to 20-95% while maintaining high recoverability
2Stress or pressure
If crosslinking density is decreased to improve stress relaxation properties of urethane resins, then stress relaxation is improved, but recoverability deteriorates
Solution Approach 1:
The patent uses a composite system where polyrotaxane provides stress relaxation through its unique molecular structure with moderate crosslinking, while thermosetting resin provides the necessary recoverability and structural integrity, allowing both properties to coexist without compromising either
Solution Approach 2:
The patent creates different local properties within the composite material: polyrotaxane domains provide stress relaxation and flexibility, while thermosetting resin domains provide structural strength and shape recovery, with each component optimized for its specific function
3Temperature
If epoxy resins are used to achieve excellent heat resistance and chemical resistance, then thermal and chemical stability are improved, but flexibility and adaptability to deformation deteriorate
Solution Approach 1:
The patent combines epoxy resin (providing heat resistance and chemical resistance) with polyrotaxane (providing flexibility and stress relaxation), creating a composite that maintains thermal stability while achieving the flexibility needed for deformation and shape recovery
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 effectively reduces residual stress, minimizing detachment and breakage, and enables flexible materials to maintain shape integrity under deformation, suitable for flexible display devices and various technical fields.
Implementation Method 1
a resin composition which is capable of undergoing elastic deformation, has little residual strain rate and exhibits stress relaxation properties
Implementation Method 2
exhibiting stress relaxation properties... reducing the applied stress so as to reduce the residual stress
Data Source
AI summary
The present invention is a resin composition characterized by being able to undergo elastic deformation, having little residual strain rate and exhibiting stress relaxation properties. More specifically, the present invention relates to a resin composition wherein the stress relaxation rate (R) and the residual strain rate (α), as measured in a prescribed extension-restoration test, are as follows: 20%≤R≤95% and 0%≤α≤3%.