Siloxane-Imide Copolymer Composition for Low-Temperature Cure
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Solution Overview
Problem
Existing curable silicone-based materials are limited to stability at temperatures below 275°C, while organic polymers like polyimide and polybenzimidazole face processability and flexibility issues, making them unsuitable for applications requiring high heat stability and flexibility across a wide temperature range.
Innovation Solution
An olefin terminated siloxane-imide copolymer and an addition curable silicone-imide composition are developed, featuring a siloxane-imide copolymer with alkenyl functional groups, a polyorganohydrogensiloxane, a hydrosilylation reaction catalyst, and optional additives, which cure at low temperatures and exhibit thermal stability up to 600°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If curable silicone-based materials are used, then flexibility and processability are improved, but heat stability deteriorates (stable only up to 275°C)
Solution Approach 1:
The patent employs siloxane-imide copolymers that combine siloxane segments (providing flexibility and processability) with imide segments (providing high heat stability). This composite polymer structure allows the material to simultaneously achieve the desirable properties of both parent materials, enabling flexibility at room temperature and thermal stability up to 600°C or higher.
2Temperature
If organic polymers like polyimide are used, then heat stability is improved (stable above 400°C), but processability and flexibility deteriorate
Solution Approach 1:
The siloxane-imide copolymer structure integrates rigid imide rings (providing thermal stability) with flexible siloxane backbones (providing processability and flexibility). This molecular-level composite allows the material to be processed like conventional silicones while maintaining polyimide-level heat resistance.
Solution Approach 2:
The patent modifies the polymer structure by incorporating specific imide ring structures (e.g., pyromellitic diimide, 3,3'-oxadispiro[4.0]fluorene-2,7-dicarboxylic diimide) into the siloxane chain, changing the thermal parameters of the base silicone material to achieve high-temperature stability while preserving flexibility through the siloxane segments.
3Temperature
If siloxane modified polyimide materials are used, then heat stability and thermal conductivity are improved, but processability deteriorates
Solution Approach 1:
The patent creates processable siloxane-imide copolymers where the siloxane segments provide chain flexibility and processability, while the imide segments provide thermal stability. This reverses the conventional approach by making the traditionally rigid polyimide processable through siloxane modification at the molecular level.
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 composition provides a heat-stable material with superior thermal stability and flexibility, suitable for applications involving extreme temperature changes, including aerospace, electronics, and automotive components.
Implementation Method 1
an addition curable silicone-imide composition comprising: (A) an alkenyl functional siloxane-imide copolymer... (C) a polyorganohydrogensiloxane... (D) a hydrosilylation reaction catalyst
Data Source
AI summary
A heat stable siloxane-imide copolymer and a curable silicone adhesive composition comprising such a siloxane-imide copolymer is shown and described herein. The composition includes an alkenyl silicone, a silicone hydride based cross linker, hydrosilylation catalyst and additives that is curable at relatively low temperatures and shows good heat stability.