Anionic Epoxy-Maleimide Adhesive Composition for Humid Electronics Packaging
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Solution Overview
Problem
Existing adhesive compositions for electronics packaging struggle to combine the high temperature stability and hydrophobicity of maleimide-terminated polyimides with the strong adhesion properties of epoxy resins, particularly under humid conditions.
Innovation Solution
A curable adhesive composition comprising maleimide and epoxy components, along with an anionic curing catalyst, without free-radical initiators, which can include fillers and reactive diluents, to enhance adhesion and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If maleimide-terminated polyimides are used to achieve high temperature stability and hydrophobicity, then thermal stability is improved, but adhesion strength deteriorates
Solution Approach 1:
The patent combines maleimide-terminated polyimide with epoxy resin to create a composite adhesive composition. The maleimide component provides high temperature stability and hydrophobicity, while the epoxy component contributes strong adhesion properties. This composite approach allows the final material to exhibit both thermal stability and strong adhesion, resolving the contradiction between these two properties.
2Strength
If epoxy resins are used to achieve strong adhesion properties, then adhesion strength is improved, but hydrophobicity deteriorates
Solution Approach 1:
The patent creates a composite system where epoxy resin and maleimide-terminated polyimide work synergistically. The epoxy provides the adhesion strength, while the maleimide component compensates for the reduced hydrophobicity by providing its own hydrophobic character and moisture resistance. The combination achieves both strong adhesion and adequate hydrophobicity.
3Productivity
If free-radical initiators are used for curing, then curing speed is improved, but adhesion under humid conditions deteriorates
Solution Approach 1:
The patent changes the curing mechanism from free-radical initiation to anionic curing. This parameter change in the curing chemistry eliminates the problem of poor adhesion under humid conditions that occurs with free-radical initiators, while still achieving adequate curing speed through the anionic polymerization mechanism. The anionic curing catalyst enables the system to cure effectively without compromising adhesion in humid environments.
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 achieves improved adhesion and thermal stability, suitable for various electronics applications, including die-attach pastes, flexible copper clad laminates, and conformal coatings, with enhanced properties such as high shear strength and low dielectric constants.
Implementation Method 1
A curable adhesive composition comprising maleimide and epoxy components, along with an anionic curing catalyst
Data Source
AI summary
The present invention provides compositions, including die attach adhesives, coatings and underfill materials, which are useful in electronics packaging and the composite fields. Specifically, the invention provides liquid and very low melting epoxy-maleimide compositions that co-cure upon the addition of an anionic cure catalyst in the absence of any other cure catalyst.