Adhesive Folding Stability Prediction via Rheological Analysis
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Solution Overview
Problem
Existing methods fail to accurately predict the folding stability of adhesives for foldable displays, which is crucial for maintaining the flexibility and durability of these devices under repeated deformation conditions.
Innovation Solution
The method involves measuring initial stress and strain recovery using a dynamic mechanical analyzer (DMA) in the stretching property measurement, and applying Equation 1 to calculate the predictive folding stability, which combines these factors to select an adhesive with excellent folding stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional adhesive evaluation methods are used, then the evaluation process is simple, but the prediction accuracy of folding stability is insufficient
Solution Approach 1:
The patent changes the evaluation parameters from conventional simple tests to specific rheological parameters (storage modulus G', loss modulus G'', tan δ) measured by DMA under controlled temperature and frequency conditions. This parameter transformation enables accurate prediction of folding stability by correlating these rheological properties with adhesive performance under repeated folding conditions.
Solution Approach 2:
The patent replaces direct mechanical folding tests with rheological measurement using dynamic mechanical analyzer (DMA). By measuring viscoelastic properties (storage modulus, loss modulus, tan δ) under simulated folding conditions, the method substitutes complex mechanical deformation testing with more controllable and precise rheological characterization, achieving better prediction accuracy.
2Adaptability or versatility
If adhesive is exposed to repeated deformation conditions, then the foldable display achieves flexibility, but deformation problems occur over time
Solution Approach 1:
The patent performs preliminary evaluation of adhesive rheological properties before actual folding application. By measuring storage modulus, loss modulus, and tan δ under simulated folding conditions (temperature, frequency, strain), the method predicts folding stability in advance, allowing selection of adhesives that will maintain reliability under repeated deformation conditions.
Solution Approach 2:
The patent establishes a feedback mechanism by correlating rheological measurement results with actual folding stability performance. The tan δ value and other rheological parameters serve as feedback indicators that predict how the adhesive will perform under repeated folding, enabling optimization of adhesive formulation for both flexibility and long-term reliability.
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
This approach significantly increases the accuracy of predicting folding stability, ensuring the adhesive's performance by achieving a high Pearson correlation coefficient of 0.95 with actual folding test results, identifying suitable adhesives like samples A and D with a folding stability value of 40000 or more.
Implementation Method 1
measuring initial stress and strain recovery of the adhesive by using a dynamic mechanical analyzer (DMA) in the stretching property measurement
Data Source
AI summary
The present invention relates to a method of deriving significant factors of rheological properties, which influence folding stability for developing an adhesive with excellent folding stability, and predicting folding stability through the same. It is possible to select an adhesive with excellent folding stability by measuring initial stress and a strain recovery rate as the significant factors, and measuring predicted folding stability (predicted number of times of folding) therefrom.