Polyimide Leftover Sintering for Solvent-Free Recycling
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Solution Overview
Problem
Existing methods for recycling semi-finished polyimide products are not suitable due to their insolubility in organic solvents, making it difficult to reuse or recycle these materials effectively.
Innovation Solution
A process involving sintering semi-finished polyimide leftovers at temperatures ranging from 250 to 550°C and pressures from 200 to 2,000 kg/cm² to produce recycled semi-finished polyimide products, which can be used alone or mixed with virgin polyimide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional recycling methods (dissolving or filler reuse) are used for polyimide waste, then films can be recycled, but sintered polyimide products cannot be recycled because they are insoluble in organic solvents
Solution Approach 1:
The patent changes the processing parameters from chemical dissolution to thermal-mechanical sintering. By heating the polyimide leftovers to temperatures between 200-500°C under pressure (1-100 atm), the material becomes sufficiently plastic to be reformed into new products, bypassing the insolubility issue entirely through parameter change from chemical to thermal processing
Solution Approach 2:
The patent replaces the chemical dissolution mechanism with a thermal-mechanical sintering process. Instead of using organic solvents to dissolve and reprocess the polyimide, the invention applies heat and pressure to directly sinter the leftovers into new forms, substituting chemical action with physical thermal-mechanical action
2Adaptability or versatility
If sintering is used to process polyimide leftovers, then recyclability is achieved, but high temperatures (250-550°C) and pressures (200-2000 kg/cm²) are required
Solution Approach 1:
The patent applies partial sintering rather than complete melting. By heating to 250-550°C (below the decomposition temperature) and applying pressure, only sufficient plasticity is achieved for reforming, avoiding excessive energy input that would be required for complete melting or decomposition while still enabling recyclability
Solution Approach 2:
The patent performs preliminary classification and preparation of the polyimide leftovers before sintering. By sorting and preparing the material in advance, the actual sintering process can be optimized and performed more efficiently, reducing the total energy requirement for the recycling operation
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 process recycles semi-finished polyimide products, maintaining thermal properties and mechanical resilience at high temperatures, enabling the reuse of valuable materials.
Implementation Method 1
processing the leftovers of the at least one semi-finished polyimide product by sintering at a temperature ranging from 250 to 550°C
Implementation Method 2
pressures from 200 to 2,000 kg/cm²
Data Source
Figure 1
AI summary
The present invention relates to a process for recycling of at least one semi-finished polyimide product, a recycled semi-finished polyimide product obtainable by the process and an article comprising the recycled semi-finished polyimide product.