Polyimide Fiber Paper with Thermoplastic Bonding for Heat Insulation
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Solution Overview
Problem
Existing polyimide film technologies face limitations in heat insulation, gas and liquid permeability, and are costly and heavy due to increased thickness, while methods for polyimide nonwoven fabrics either compromise polyimide properties or require specialized and expensive equipment for uniform thickness and wide sheet production.
Innovation Solution
A method for manufacturing polyimide fiber paper using shaved short fibers of non-thermoplastic polyimide temporarily bonded with a water-soluble or water-insoluble thermoplastic polymer having a melting point lower than the polyimide's glass transition point, allowing for the creation of a lightweight, high-functionality material with enhanced heat resistance and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyimide film thickness is increased to improve heat insulation and reduce weight, then heat insulation performance improves, but cost and weight increase
Solution Approach 1:
The patent uses a nonwoven fabric structure with inherent porosity and air pockets between fibers, which provides excellent heat insulation performance. The porous structure traps air, a poor thermal conductor, thereby improving heat insulation without requiring increased material thickness or weight.
2Temperature
If polyimide film thickness is increased to improve heat insulation, then heat insulation performance improves, but cost increases
Solution Approach 1:
The nonwoven fabric's porous structure provides high heat insulation performance per unit weight and cost, eliminating the need for thick, expensive film layers.
Solution Approach 2:
The patent creates a composite structure combining polyimide fibers with other materials in a nonwoven fabric, achieving cost-effective heat insulation through material synergy rather than relying on expensive thick polyimide films.
3Strength
If polyimide short fibers are heated to glass transition point or higher for thermal welding, then fiber bonding is achieved, but inherent polyimide properties are lost or reduced
Solution Approach 1:
The patent introduces a thermoplastic resin as an intermediary bonding agent that melts at lower temperatures to bond polyimide fibers together. This mediator enables fiber bonding without exposing the polyimide to temperatures that would degrade its inherent high-temperature resistance and other properties.
Solution Approach 2:
The patent changes the bonding mechanism from direct high-temperature thermal welding to low-temperature bonding using a thermoplastic resin with lower melting point, thereby maintaining polyimide's inherent properties while achieving sufficient fiber bonding strength.
4Temperature
If non-thermoplastic polyimide is used for high heat resistance, then heat resistance is maintained, but manufacturing requires specialized equipment and uniform thickness is difficult to achieve
Solution Approach 1:
The patent changes the manufacturing approach from solution spinning requiring specialized equipment to a dry nonwoven fabric process using conventional textile equipment, while maintaining heat resistance through material selection rather than process complexity.
Solution Approach 2:
The patent replaces the complex solution spinning and high-speed airflow capture system with a simpler mechanical nonwoven fabric formation process, reducing device complexity while achieving uniform thickness through conventional textile manufacturing techniques.
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 method enables the production of polyimide fiber paper with a high thermoplastic polyimide content, maintaining inherent polyimide properties such as heat resistance, flame retardancy, and electric insulation, while being lightweight and cost-effective, and allows for lamination with other materials to enhance characteristics.
Implementation Method 1
a water-soluble and/or water-insoluble thermoplastic polymer having a melting point lower than a glass transition point of a polyimide
Implementation Method 2
a polyimide fiber paper intermediate structure Z1 by dispersing a polyimide solution and/or polyimide precursor in the polyimide fiber paper intermediate structure X
Data Source
AI summary
A method is provided for manufacturing a polyimide fiber paper intermediate structure, which includes: a short fiber preparing step for preparing shaved short fibers of a non-thermoplastic polyimide; and an intermediate structure forming step for forming a polyimide fiber paper intermediate structure in which the short fibers are temporarily bonded using a water-soluble and/or water-insoluble thermoplastic polymer having a melting point lower than a glass transition point of a polyimide.