Thermoplastic Polyimide Resin Low Melting Point High Tg
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Solution Overview
Problem
Current crystalline thermoplastic polyimide resins face challenges in achieving a low melting point while maintaining a high glass transition temperature, which is essential for improved moldability and heat resistance, and existing solutions often require specialized monomers and complex synthesis processes, limiting practical mass production.
Innovation Solution
A thermoplastic polyimide resin is developed with a specific combination of structural units, including alicyclic and aromatic components, which allows for a low melting point of 360°C or less and a high glass transition temperature of 200°C or more, enhancing crystallization rate and moldability without the need for highly specialized monomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the melting point of a polyimide is decreased to improve moldability, then the glass transition temperature also decreases, which deteriorates heat resistance
Solution Approach 1:
The invention changes the chemical structure parameters of the polyimide by introducing specific structural units (formulae 1-4) with controlled ratios. This modifies the molecular chain rigidity and intermolecular forces, enabling independent optimization of melting point and glass transition temperature. The copolymer structure allows tuning of crystallization behavior without proportionally affecting Tg.
Solution Approach 2:
The invention creates a composite polyimide structure combining rigid aromatic units (for high Tg) and flexible aliphatic/cyclic units (for lower melting point and improved crystallization). This composite approach at the molecular level allows the material to exhibit both high heat resistance and improved moldability simultaneously.
2Temperature
If a polyimide is molded at high temperature and high pressure for prolonged time to achieve high heat resistance, then the molding process becomes complex and expensive
Solution Approach 1:
The invention changes the thermal parameters of the polyimide by controlling the ratio of structural units to achieve a melting point of 360°C or lower. This enables standard injection molding processes to be used, eliminating the need for specialized high-temperature equipment and prolonged molding cycles, thereby simplifying the manufacturing process while maintaining heat resistance.
3Ease of manufacture
If flexible structures are introduced into a rigid aromatic polyimide to achieve a melting point, then the melting point becomes excessively high (388°C) and crystallization rate becomes too slow for practical molding
Solution Approach 1:
The invention optimizes the parameters of flexibility introduction by using specific structural units with controlled ratios (40-70 mol% of formulae 1 and 2). This moderate introduction of flexible groups lowers the melting point to 360°C or below and accelerates crystallization, unlike the excessive flexibility in Aurum that causes high melting point and slow crystallization.
Solution Approach 2:
The invention applies local quality by distributing flexible structural units (formulae 2 and 3) at specific positions within the polymer chain rather than uniformly throughout. This localized flexibility promotion enables faster crystallization kinetics while maintaining overall structural integrity and appropriate melting characteristics.
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 achieves a balance of low melting point and high glass transition temperature, enabling efficient injection molding and extrusion molding with improved heat resistance and crystallization rates, making it suitable for industrial-scale production.
Implementation Method 1
A polyimide having crystallinity is further enhanced in the heat resistance, the strength and the chemical resistance thereof
Implementation Method 2
A thermoplastic polyimide resin containing a repeating structural unit represented by formula (1) and a repeating structural unit represented by 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 from 40 to 70% by mol
Data Source
AI summary
A thermoplastic 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 from 40 to 70% by mol: 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 12 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.