Polyimide Resin Composition for Low-Loss Metal Foil Adhesion
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Solution Overview
Problem
Existing metal-clad laminated boards and flexible printed wiring boards using polyimide resins face challenges in achieving low transmission loss and sufficient adhesion between the polyimide resin layer and metal foil, particularly due to surface roughness from recesses and projections on the metal foil.
Innovation Solution
A polyimide resin precursor is formulated with specific ratios of diamines (p-phenylenediamine, bis(aminophenoxy)benzene, and 2-(4-aminophenyl)benzoxazol-5-amine) and acid anhydride (biphenyl tetracarboxylic dianhydride) to enhance adhesion and reduce dielectric properties, resulting in a polyimide resin with low dielectric constant, dissipation factor, and water absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the surface roughness of metal foil is reduced by downsizing recesses and projections, then transmission loss is decreased, but adhesion between the metal foil and polyimide resin layer becomes insufficient
Solution Approach 1:
The invention changes the chemical composition parameters of the polyimide resin by incorporating specific diamines (p-phenylenediamine, 4,4'-diaminodiphenylsulfone, and 2,2'-dimethyl-4,4'-diaminobiphenyl) in controlled molar ratios. This chemical parameter modification enables the resin to achieve both low dielectric properties for reduced transmission loss and sufficient adhesion to metal foils with small surface roughness
Solution Approach 2:
The invention creates a composite system by combining multiple diamine components with acid anhydride components to form a polyimide resin with synergistic properties. The specific combination of aromatic diamines provides both the dielectric performance needed for low transmission loss and the adhesive characteristics required for bonding to smooth metal surfaces
2Loss of energy
If polyimide resin with low dielectric constant and dissipation factor is used, then transmission loss is reduced, but adhesion to metal foil with small surface roughness becomes insufficient
Solution Approach 1:
The invention modifies the chemical structure parameters of the polyimide resin by selecting specific diamines with aromatic rings and sulfone groups that provide both low dielectric constant (3.5 or less) and adequate adhesion. The controlled molar ratios of different diamines optimize the balance between dielectric performance and adhesive strength
Solution Approach 2:
The invention imparts different local properties to the polyimide resin: the aromatic diamine structure provides low dielectric constant for reduced transmission loss, while the functional groups in the diamine structure provide adhesion capability. This local quality differentiation within the resin structure resolves the contradiction between dielectric performance and adhesion
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 solution provides a polyimide resin with improved adhesion to metal foils, reducing transmission loss and maintaining low dielectric properties, thus enhancing the performance of metal-clad laminated boards and flexible printed wiring boards.
Implementation Method 1
A polyimide resin precursor obtained by allowing a diamine and an acid anhydride to react with each other
Data Source
AI summary
A polyimide resin precursor is obtained by allowing a diamine and an acid anhydride to react with each other. The diamine includes p-phenylenediamine, a bis(aminophenoxy)benzene, and 2-(4-aminophenyl)benzoxazol-5-amine. The acid anhydride includes a biphenyl tetracarboxylic dianhydride. The content of the p-phenylenediamine is 30 to 75% by mol, the content of the bis(aminophenoxy)benzene is 10 to 30% by mol, and the content of the 2-(4-aminophenyl)benzoxazol-5-amine is 10 to 50% by mol, with respect to the total of the diamine. The content of the biphenyl tetracarboxylic dianhydride is 78% by mol or more with respect to the total of the acid anhydride.