Polyimide Precursor Solution Crack Prevention
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Solution Overview
Problem
Polyimide shaped articles often suffer from cracks due to uneven coating and mechanical strength issues, which can arise from polyimide precursor solutions with either excessively high or low molecular weights, leading to viscosity problems and reduced toughness.
Innovation Solution
A polyimide precursor solution with a weight average molecular weight of 10,000 or more and a smaller amount of lower molecular weight components, balanced to achieve a GPC peak area proportion of 0.70 to 0.98, is used to form a coating film that reduces viscosity and enhances flexibility while minimizing crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyimide precursor solution with high molecular weight is used, then mechanical strength is improved, but viscosity increases causing uneven coating
Solution Approach 1:
The patent segments the polyimide precursor population into two distinct molecular weight regions (Region A with Mw≥10,000 and Region B with Mw<10,000). This segmentation allows the high molecular weight components to provide mechanical strength while the low molecular weight components maintain solution流动性 and coating uniformity, resolving the contradiction between strength and ease of manufacture.
Solution Approach 2:
The patent changes the molecular weight distribution parameters by controlling the area ratio a/(a+b) to be 0.70-0.98, where a is the area of Region A and b is the area of Region B. This parameter optimization ensures that the majority of polyimide precursor molecules have high molecular weight for strength, while a controlled minority have low molecular weight to prevent excessive viscosity and ensure uniform coating.
2Ease of manufacture
If polyimide precursor solution with low molecular weight is used, then viscosity is reduced improving coating uniformity, but mechanical strength decreases leading to cracks
Solution Approach 1:
The patent segments the polyimide precursor population into two distinct molecular weight regions (Region A with Mw≥10,000 and Region B with Mw<10,000). This segmentation allows the high molecular weight components to provide mechanical strength while the low molecular weight components maintain solution流动性 and coating uniformity, resolving the contradiction between strength and ease of manufacture.
Solution Approach 2:
The patent changes the molecular weight distribution parameters by controlling the area ratio a/(a+b) to be 0.70-0.98, where a is the area of Region A and b is the area of Region B. This parameter optimization ensures that the majority of polyimide precursor molecules have high molecular weight for strength, while a controlled minority have low molecular weight to prevent excessive viscosity and ensure uniform coating.
3Stability of the object's composition
If polyimide precursor with excessively high molecular weight is used, then toughness is improved, but viscosity increases causing coating unevenness and cracks
Solution Approach 1:
The patent segments the polyimide precursor population into two distinct molecular weight regions (Region A with Mw≥10,000 and Region B with Mw<10,000). This segmentation allows the high molecular weight components to provide mechanical strength while the low molecular weight components maintain solution流动性 and coating uniformity, resolving the contradiction between strength and ease of manufacture.
Solution Approach 2:
The patent changes the molecular weight distribution parameters by controlling the area ratio a/(a+b) to be 0.70-0.98, where a is the area of Region A and b is the area of Region B. This parameter optimization ensures that the majority of polyimide precursor molecules have high molecular weight for strength, while a controlled minority have low molecular weight to prevent excessive viscosity and ensure uniform coating.
Data Source
AI summary
A polyimide precursor solution contains a polyimide precursor, wherein in the case where the polyimide precursor is analyzed by gel permeation chromatography, the elution curve of the polyimide precursor has a region A including a higher-molecular-weight peak and a region B including a lower-molecular-weight peak; a weight average molecular weight determined from the region A in terms of polystyrene is approximately 10,000 or more, and a weight average molecular weight determined from the region B in terms of polystyrene is approximately less than 10,000; and when the area of the region A is a and the area of the region B is b, the polyimide precursor satisfies Equation (1)a/(a+b)=approximately from 0.70 to 0.98. Equation 1: