Resin Composition for Printed Wiring Boards
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Solution Overview
Problem
Conventional epoxy resin-based printed wiring boards fail to achieve a balance of high glass transition temperature and low dielectric constant, with monofunctional acid anhydrides being volatile and affecting composition ratios during prepreg production, leading to inadequate properties.
Innovation Solution
A resin composition combining an epoxy resin with a first acid anhydride having one cyclic acid anhydride group and a second acid anhydride with multiple acid anhydride groups, where the unsaturated bond concentration is limited to 0.7% or less, and the acid anhydride to epoxy resin ratio is between 0.05 and 1.1, to achieve a high glass transition temperature and low dielectric constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If monofunctional acid anhydride is used as curing agent, then glass transition temperature increases, but composition ratio becomes unstable due to volatilization
Solution Approach 1:
A polyfunctional acid anhydride is introduced as an intermediary substance to suppress the volatilization of monofunctional acid anhydride. The polyfunctional acid anhydride acts as a trapping agent that binds the volatile monofunctional acid anhydride through ester bond formation, preventing its loss during heating processes while still allowing the monofunctional acid anhydride to contribute to high glass transition temperature in the cured product.
Solution Approach 2:
The resin composition is prepared in advance with both monofunctional and polyfunctional acid anhydrides mixed together before the curing process. This preliminary combination ensures that when heating occurs during prepreg production or curing, the polyfunctional acid anhydride is already present to suppress volatilization of the monofunctional acid anhydride, maintaining stable composition ratios throughout the manufacturing process.
2Quantity of substance
If acid anhydride-based curing agent is used, then dielectric constant decreases, but glass transition temperature becomes difficult to increase
Solution Approach 1:
The invention changes the functional parameters of the curing agent system by combining acid anhydrides with different functionality. The monofunctional acid anhydride (with one cyclic acid anhydride group) provides low dielectric constant, while the polyfunctional acid anhydride (with multiple acid anhydride groups) provides high crosslinking density for high glass transition temperature. This parameter combination resolves the contradiction between low dielectric constant and high glass transition temperature.
Solution Approach 2:
The curing agent system is designed as a composite of two different acid anhydride types: monofunctional acid anhydride (providing low dielectric constant) and polyfunctional acid anhydride (providing high crosslinking and glass transition temperature). This composite curing agent system achieves properties that neither component could achieve alone, simultaneously providing low dielectric constant and high glass transition temperature.
3Temperature
If monofunctional acid anhydride is used, then glass transition temperature increases, but volatilization occurs during prepreg production
Solution Approach 1:
The invention converts the harmful volatilization property of monofunctional acid anhydride into a beneficial effect. The polyfunctional acid anhydride is deliberately added to react with and trap the volatile monofunctional acid anhydride, converting its harmful volatility into a useful crosslinking mechanism. The ester bonds formed during this process lock the monofunctional acid anhydride in place, preventing volatilization while maintaining its contribution to high glass transition temperature in the final cured product.
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 combination effectively suppresses volatilization of the first acid anhydride, maintaining a stable composition ratio and achieving a high glass transition temperature while maintaining a low dielectric constant, thus enhancing the thermal and electrical properties of printed wiring boards.
Implementation Method 1
The resin composition includes an epoxy resin and a curing agent. The curing agent includes a first acid anhydride and a second acid anhydride... The combination can achieve a high glass transition temperature and a low dielectric constant.
Data Source
AI summary
A resin composition contains an epoxy resin, and a curing agent including a first acid anhydride and a second acid anhydride. An unsaturated bond concentration in the second acid anhydride is not higher than 0.7%. The unsaturated bond concentration is represented by following formula (1). The ratio of the number of acid anhydride equivalents of the first acid anhydride to the number of epoxy equivalents of the epoxy resin is between 0.05 and 0.5 (inclusive). The ratio of the total number of acid anhydride equivalents of the first acid anhydride and the second acid anhydride to the number of epoxy equivalents is between 0.5 and 1.1 (inclusive).Unsaturated bond concentration={(number of unsaturated bonds per molecule)/(molecular weight)}/(number of acid anhydride groups per molecule)×100 (1)