Aliphatic Bismaleimide Epoxy Composition for Heat and Tracking Resistance
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Solution Overview
Problem
Existing resin compositions for encapsulating SiC power semiconductors face a trade-off between high heat resistance and excellent tracking resistance, with maleimide-based resins offering poor tracking resistance and epoxy resin-containing compositions lacking sufficient heat resistance.
Innovation Solution
A thermosetting resin composition comprising an aliphatic bismaleimide compound with a divalent aliphatic hydrocarbon group of 5 to 12 carbon atoms and an epoxy resin with multiple epoxy groups, along with a curing accelerator, to achieve a cured product with high glass transition temperature, heat resistance, and excellent tracking resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If maleimide-based resin is used to achieve high heat resistance, then glass transition temperature and weight loss temperature increase, but tracking resistance deteriorates
Solution Approach 1:
The patent uses a composite material system combining maleimide-based resin (for high heat resistance with Tg > 300°C and Td5 > 400°C) with alicyclic structure-containing resin (for excellent tracking resistance with CTI ≥ 600V). This composite approach allows both high heat resistance and excellent tracking resistance to be achieved simultaneously, resolving the technical contradiction between these two properties.
2Reliability
If alicyclic structure is introduced into epoxy resin to improve tracking resistance, then tracking resistance increases, but heat resistance deteriorates
Solution Approach 1:
The patent combines alicyclic structure-containing epoxy resin (providing tracking resistance with CTI ≥ 600V) with maleimide-based resin (providing heat resistance with Tg > 300°C and Td5 > 400°C). The synergistic effect of this composite system achieves both excellent tracking resistance and high heat resistance, resolving the contradiction between these properties.
3Temperature
If aromatic rings are increased to improve heat resistance, then heat resistance increases, but tracking resistance worsens due to carbonized conductive path formation
Solution Approach 1:
The patent changes the chemical structure parameter by using aliphatic maleimide-based resin instead of aromatic maleimide resin. This structural modification maintains the high heat resistance (Tg > 300°C, Td5 > 400°C) while eliminating the formation of carbonized conductive paths, thereby achieving excellent tracking resistance (CTI ≥ 600V) without the harmful effects of aromatic ring-containing resins.
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 cured product with high heat resistance and excellent tracking resistance, suitable for encapsulating power semiconductors, ensuring durability and safety under high thermal and electrical stress.
Implementation Method 1
a resin composition containing a maleimide-based resin has a glass transition temperature (Tg) higher than 300° C. and a 5% weight loss temperature (Td5) higher than 400° C. This is presumably due to the high crosslink density that is characteristic of the maleimide-based resin
Implementation Method 2
excellent tracking resistance can be achieved by introducing an alicyclic structure into an epoxy resin structure. This is presumably because the formation of carbonized conductive paths, which are the cause of tracking, is inhibited by reducing the proportion of aromatic rings in the structure
Data Source
AI summary
A thermosetting resin composition contains (A) an aliphatic bismaleimide compound represented by formula (1):where in formula (1), A is a divalent aliphatic hydrocarbon group having 5 to 12 carbon atoms, and (B) an epoxy resin containing two or more epoxy groups in one molecule. The amount of component (A) is in the range of 20% to 95% by mass based on the total of component (A) and component (B).