Polymer Viscosity Curve Estimation Across Melting and Curing
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Solution Overview
Problem
There is no method to estimate the viscosity of an epoxy resin during its whole curing process, which is crucial for producing high-quality electronic devices with polymeric materials.
Innovation Solution
A method involving acquiring viscosity values at different temperatures and heating rates, splitting the viscosity curve into melting and curing curves, and fitting these curves using Eyring's equation to estimate the viscosity curve accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If viscosity is measured at multiple temperatures and heating rates, then measurement precision is improved, but device complexity and measurement time increase
Solution Approach 1:
The viscosity curve is segmented into distinct regions (melting region and curing region) based on the polymeric material's thermal behavior. By dividing the measurement curve into segments, the patent enables precise estimation in each region using appropriate models, thereby improving overall measurement precision without requiring a single complex measurement system to handle all conditions simultaneously
Solution Approach 2:
The patent performs preliminary DSC analysis to determine characteristic temperatures (Tg, Tm, Tc) and curing behavior before conducting viscosity measurements. This preliminary action allows the viscosity measurement system to be configured appropriately for specific material behaviors, reducing the complexity of the measurement system while maintaining high precision through pre-acquired material characteristics
2Manufacturing precision
If viscosity curve is split into melting and curing curves with separate fitting, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The viscosity curve is divided into melting and curing segments with separate fitting procedures. This segmentation allows each segment to be modeled with appropriate physical chemistry models, improving manufacturing precision by capturing the distinct mechanisms of each phase change and chemical reaction
Solution Approach 2:
The patent establishes continuous relationships between heating rate and viscosity at characteristic temperatures (Tg, Tm, Tc) by ensuring continuity of the fitted curves and their derivatives. This continuous action across segment boundaries enables precise manufacturing predictions without requiring time-consuming discrete measurements at every condition
3Measurement precision
If DSC analysis is performed to determine curing degree, then measurement precision is improved, but loss of time and use of energy increase
Solution Approach 1:
DSC analysis is performed as a preliminary step to determine material-specific parameters (Tg, Tm, Tc, curing enthalpy) before viscosity measurements. This preliminary characterization enables the viscosity model to use pre-determined material constants, improving measurement precision while reducing the time required for subsequent viscosity curve fitting
Solution Approach 2:
The patent uses DSC-determined characteristic temperatures and curing degree as intermediary parameters to link thermal analysis with viscosity measurement. These intermediary values serve as boundary conditions and validation points, improving the precision of viscosity estimation without requiring continuous real-time monitoring during the entire curing process
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
Enables precise estimation of viscosity throughout the curing process, ensuring accurate production processes for polymeric materials in electronic devices.
Implementation Method 1
splitting the determined viscosity curve into at least one determined melting curve and at least one determined curing curve
Implementation Method 2
determining at least one fitted curing curve per determined curing curve
Implementation Method 3
at least one melting curve and at least one curing curve can be fitted using the Eyring's equation
Data Source
AI summary
The invention relates to a method for estimating a viscosity curve of a polymeric material, the method comprising: acquiring viscosity values of the polymeric material at different temperatures (T) under different heating rates (β); determining at least one viscosity curve of the polymeric material depending on the measured viscosities for each heating rate (β); splitting the viscosity curves into at least one determined melting curve and at least one determined curing curve per determined viscosity curve; determining at least one fitted melting curve per determined melting curve; determining at least one fitted curing curve per determined curing curve; and estimating the viscosity curve of the polymeric material by combining the fitted melting curve and the fitted curing curve.