Polyimide Resin Copolymer for Printed Wiring Boards
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Solution Overview
Problem
Existing polyimide resins used in printed wiring boards suffer from high melt viscosity, poor embedding properties, and reduced adhesion to base materials, leading to issues with bubble formation and insufficient heat resistance.
Innovation Solution
A polyimide resin composed of a copolymer of a straight chain aliphatic diamino compound and an aromatic diamino compound, combined with a tetrabasic acid dianhydride, which results in a resin composition with improved embedding properties, adhesion, and enhanced heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyimide resin with long chain alkyl or dimer diamine is used to achieve low dielectric loss tangent, then dielectric property is improved, but melt viscosity increases and embedding property deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the diamine component by introducing specific side chain structures (cyclic structures, aromatic rings) with controlled carbon numbers (6-12) and specific functional group arrangements. This modifies the polymer chain flexibility and intermolecular forces, achieving low melt viscosity while maintaining low dielectric loss tangent through optimized molecular architecture rather than simply increasing chain length
Solution Approach 2:
The patent uses copolymerization combining aliphatic diamines with specific cyclic structures and aromatic diamines. This composite molecular structure integrates the advantages of both components: the aliphatic portion provides flexibility and low viscosity, while the aromatic portions contribute to thermal stability and low dielectric loss, achieving both embedding property and dielectric property simultaneously
2Reliability
If polyimide resin with long chain alkyl or dimer diamine is used to achieve low dielectric loss tangent, then dielectric property is improved, but adhesion to base material is reduced
Solution Approach 1:
The patent introduces local aromatic structures and cyclic groups at specific positions within the polymer chain. These localized rigid structures with polar functional groups enhance interfacial adhesion to metal foils and base materials through improved chemical bonding and physical interaction, while the overall chain flexibility is maintained by the aliphatic segments, thus resolving the adhesion-dielectric property contradiction
3Reliability
If polyimide resin with long chain alkyl or dimer diamine is used to achieve low dielectric loss tangent, then dielectric property is improved, but heat resistance becomes insufficient
Solution Approach 1:
The patent employs copolymerization of aliphatic diamines with cyclic structures and aromatic diamines containing heteroatoms (O, S, N). The aromatic segments with heteroatoms form rigid, thermally stable regions that raise the glass transition temperature and improve heat resistance, while the aliphatic segments maintain processability. This composite structure achieves both low dielectric loss tangent and sufficient heat resistance
Data Source
AI summary
A polyimide resin that is a copolymer of an amino compound (A) and a tetrabasic acid dianhydride (B). The amino compound (A) includes a straight chain aliphatic diamino compound (a1) and an aromatic diamino compound (a2). The straight chain aliphatic diamino compound (a1) includes amino groups at both terminals, 1 to 4 methyl groups and/or ethyl groups in a side chain and 17 to 24 carbon atom in a main chain.