Epoxy Resin Composition for Printed Wiring Boards
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Solution Overview
Problem
Conventional epoxy resin compositions for printed wiring boards lack sufficient heat resistance, adhesiveness, anti-ion migration properties, and storage stability, which are crucial for high-density LSI mounting and multilayer printed wiring boards, especially in semiconductor packaging and internet communication devices.
Innovation Solution
A resin composition combining an oxazolidone ring-containing epoxy resin, a novolac-type epoxy resin, a guanidine derivative, and an imidazole, with specific weight ratios and bromine content, to enhance heat resistance, adhesiveness, and storage stability, while maintaining insulation reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventionally employed epoxy resin composition (combination of lowly brominated epoxy resin, multifunctional epoxy resin, and curing agent) is used, then basic adhesion is achieved, but heat resistance and insulation reliability are insufficient
Solution Approach 1:
The patent uses a composite epoxy resin system combining oxazolidone ring-containing epoxy resin (providing heat resistance through isocyanuric ring structure), brominated epoxy resin (providing flame retardancy and insulation), and novolac-type epoxy resin. This multi-component composite approach achieves both high heat resistance and insulation reliability that single resin systems cannot provide
Solution Approach 2:
The patent specifies precise compositional parameters: oxazolidone ring-containing epoxy resin (A) at 5-95 wt%, brominated epoxy resin at controlled bromine content, novolac-type epoxy resin (B) at 5-95 wt%, with specific curing agents and accelerators. By optimizing these parameter ranges, the composition achieves simultaneous improvement in heat resistance and insulation reliability
2Productivity
If high wiring density is implemented in printed wiring boards, then functional integration is improved, but copper ionic migration increases causing malfunction
Solution Approach 1:
The patent adds brominated epoxy resin specifically to convert the harmful effect of copper ionic migration into a beneficial outcome. The bromine content (10-20% by weight based on resin composition) provides flame retardancy while the brominated structure creates a protective barrier that prevents copper ion migration, transforming a potential hazard into a protective mechanism
Solution Approach 2:
The patent controls the bromine content parameter within specific ranges (10-20% by weight) to optimize the balance between preventing copper ionic migration and maintaining electrical insulation properties. This parameter optimization ensures high wiring density can be achieved without copper migration issues
3Manufacturing precision
If insulation layer thickness is reduced to control signal line impedance, then signal integrity is improved, but prepreg storage stability becomes difficult to maintain
Solution Approach 1:
The patent optimizes the epoxy resin composition parameters (oxazolidone ring-containing resin, novolac-type resin ratios, curing agent content, and accelerator amount) to achieve consistent gel time and viscosity characteristics. This compositional precision ensures that even with reduced insulation layer thickness, the prepreg maintains stable storage properties and predictable processing behavior
Solution Approach 2:
The multi-component epoxy resin composite system provides balanced rheological and curing characteristics that ensure prepreg storage stability. The combination of different epoxy resins with complementary properties creates a formulation that maintains consistent flow and gelation behavior, enabling precise insulation layer thickness control
Data Source
AI summary
To provide an epoxy resin composition that can afford a printed wiring board excellent in heat resistance, adhesiveness, prepreg storage stability, and insulation reliability. An epoxy resin composition containing (A) an oxazolidone ring-containing epoxy resin, (B) a novolac-type epoxy resin, (C) a guanidine derivative, and (D) an imidazole as components, wherein the component (A) contains an isocyanuric ring as well as an oxazolidone ring and, the IR absorbance ratio of the isocyanuric ring to the oxazolidone ring is not less than 0.01 and not more than 0.1, the weight ratio of the component (A) to the component (B) is 5:95 to 95:5, the content of the component (C) and the content of the component (D) are 0.01 to 5 parts by weight and not more than 0.08 part by weight, respectively, based on 100 parts by weight of the total weight of the epoxy resins containing the component (A) and the component (B), and the bromine content based on a weight obtained by subtracting the weight of the component (C) and the weight of the component (D) from the weight of the resin composition is not less than 10% by weight and not more than 20% by weight.