Polyimide Resin Molding Processability Heat Resistance
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Solution Overview
Problem
Polyimide resins face challenges in achieving both high molding processability and heat resistance, particularly in maintaining heat aging resistance, due to their high melting points and rigidity, which limits their applications in environments requiring both mechanical strength and thermal stability.
Innovation Solution
A polyimide resin is developed with specific structural units and end groups, including a repeating structural unit with an alicyclic hydrocarbon structure and a chain aliphatic group, optimized in content ratio and structure to enhance molding processability and heat aging resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a polyimide resin is designed to have high heat resistance and rigidity, then thermal stability and strength are improved, but molding processability deteriorates due to high melting point and low flowability
Solution Approach 1:
The invention changes the chemical structure parameters of the polyimide resin by introducing specific structural units (formulae 1-4) with controlled ratios, and modifies end groups to achieve optimal balance between heat resistance and molding processability. The melting point is controlled to 250-400°C and glass transition temperature to 150-250°C through these parameter adjustments.
Solution Approach 2:
The invention creates a composite polyimide resin structure by combining multiple different structural units (formulae 1-4) in specific ratios. This composite approach allows the resin to exhibit both high heat resistance from aromatic structures and improved molding processability from aliphatic chain segments.
2Ease of manufacture
If the melting point of polyimide resin is decreased to improve molding processability, then ease of manufacture is improved, but heat resistance and strength deteriorate
Solution Approach 1:
The invention optimizes the molecular structure parameters by controlling the types and ratios of structural units, achieving a melting point range of 250-400°C and glass transition temperature of 150-250°C. This parameter optimization allows both good molding processability and maintained heat resistance.
3Strength
If a polyimide resin is designed for high strength and rigidity, then mechanical strength is improved, but thermoplasticity deteriorates due to molecular chain rigidity
Solution Approach 1:
The invention applies local quality by introducing flexible aliphatic chain segments (R2 groups with 5-16 carbon atoms) at specific locations in the molecular chain. These local flexible segments provide thermoplasticity while the aromatic structures (X1 and X2 groups) maintain overall strength and rigidity.
Solution Approach 2:
The invention changes the molecular chain flexibility parameters by incorporating structural units with aliphatic chains of controlled length (5-16 carbon atoms). This parameter adjustment enables thermoplasticity while maintaining mechanical strength through the aromatic structural components.
4Ease of manufacture
If polyimide resin is processed at high temperature and high pressure for prolonged time to achieve good molding, then molding processability is improved, but production cost increases
Solution Approach 1:
The invention changes the processing temperature parameter by designing a resin with melting point of 250-400°C, which is lower than conventional high-performance polyimides. This allows molding at reduced temperature and pressure, decreasing energy consumption and production cost while maintaining good molding processability.
Data Source
AI summary
A polyimide resin containing a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), a content ratio of the repeating structural unit of formula (1) with respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2) being 20 to 70 mol%, and the polyimide resin having a chain aliphatic group having from 5 to 14 carbon atoms at an end thereof: wherein R1 represents a divalent group having from 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure R2 represents a divalent chain aliphatic group having from 5 to 16 carbon atoms; and X1 and X2 each independently represent a tetravalent group having from 6 to 22 carbon atoms containing at least one aromatic ring.