Polyimide Resin Precursor Low Dielectric Flame Retardancy
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Solution Overview
Problem
Current polyimide resins used in flexible circuit boards suffer from high dielectric constants, dielectric tangents, water absorption rates, and lack of flame retardancy, making them unsuitable for high-frequency applications and environmentally sensitive conditions.
Innovation Solution
A polyimide resin precursor is developed with a specific composition of diamine and tetracarboxylic acid anhydride components, including p-phenylenediamine and ester-containing tetracarboxylic acid anhydrides like 3,4,3',4'-biphenyltetracarboxylic acid dianhydride, in specific proportions to achieve low dielectric properties and improved flame retardancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyimide resin includes pyromellitic acid dianhydride in high content (50 mol % or more), then the resin achieves good heat resistance and mechanical properties, but the dielectric constant and dielectric tangent increase, degrading dielectric properties
Solution Approach 1:
The patent changes the chemical composition parameters by replacing pyromellitic acid dianhydride with ester-containing tetracarboxylic acid dianhydride (TAHQ) and/or biphenyltetracarboxylic acid dianhydride (s-BPDA), achieving low dielectric constant (≤3.5) and low dielectric tangent (≤0.004) while maintaining heat resistance through proper monomer selection and ratio control
Solution Approach 2:
The patent creates a composite polyimide resin system combining multiple monomers (diamine components with TAHQ and/or s-BPDA) in specific ratios to simultaneously achieve low dielectric properties and good heat resistance, where the synergistic combination of monomers produces superior overall performance
2Strength
If polyimide resin uses conventional monomers, then the resin exhibits good mechanical properties, but the water absorption rate increases, degrading performance in high humidity environments
Solution Approach 1:
The patent modifies the monomer structure by introducing ester-containing tetracarboxylic acid dianhydride (TAHQ) and/or biphenyltetracarboxylic acid dianhydride (s-BPDA) which have lower water absorption characteristics, achieving water absorption rate ≤1.0 wt% while maintaining mechanical integrity through optimized monomer ratios
3Reliability
If liquid crystal polymers are used to achieve low dielectric properties and low water absorption rate, then the dielectric properties improve, but the adhesiveness to metal foils and heat resistance decrease
Solution Approach 1:
The patent changes the polymer chemistry by using polyimide resins with ester-containing tetracarboxylic acid dianhydride (TAHQ) and/or biphenyltetracarboxylic acid dianhydride (s-BPDA) as monomers, achieving low dielectric constant (≤3.5), low dielectric tangent (≤0.004), and low water absorption (≤1.0 wt%) while maintaining good adhesiveness to metal foils and heat resistance through the inherent properties of polyimide chemistry
Solution Approach 2:
The patent creates a composite resin system combining diamine components with TAHQ and/or s-BPDA in optimized ratios to simultaneously achieve low dielectric properties, low water absorption, good adhesiveness to metal foils, and excellent heat resistance, where the composite structure provides all required properties without compromising any single one
4Reliability
If polyimide resin is used in high-frequency applications, then the resin provides good electrical insulation, but the transmission loss increases due to high dielectric constant and dielectric tangent
Solution Approach 1:
The patent changes the dielectric parameters of the polyimide resin by replacing conventional monomers with ester-containing tetracarboxylic acid dianhydride (TAHQ) and/or biphenyltetracarboxylic acid dianhydride (s-BPDA), achieving low dielectric constant (≤3.5) and low dielectric tangent (≤0.004) that significantly reduce transmission loss in high-frequency applications while maintaining excellent electrical insulation
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 resulting polyimide resin exhibits low dielectric constant and tangent, reduced water absorption, and excellent flame retardancy, addressing the limitations of existing polyimide resins and enhancing their performance in electronic devices.
Implementation Method 1
a polyimide resin precursor obtained by allowing a diamine component and a tetracarboxylic acid anhydride component to react with each other
Data Source
AI summary
The polyimide resin precursor in the present embodiment is a polyimide resin precursor obtained by allowing a diamine component and a tetracarboxylic acid anhydride component to react with each other, wherein based on the whole of the diamine component, the content of p-phenylenediamine is 75 mol % or more; the tetracarboxylic acid anhydride component includes an ester-containing tetracarboxylic acid anhydride represented by formula (1), and at least one biphenyltetracarboxylic acid anhydride selected from the group consisting of 3,4,3′,4′-biphenyltetracarboxylic acid dianhydride, 2,3,3′,4′-biphenyltetracarboxylic acid dianhydride and 2,3,2′,3′-biphenyltetracarboxylic acid dianhydride; and based on the whole of the tetracarboxylic acid anhydride component, (i) the total of the content of the ester-containing tetracarboxylic acid anhydride and the content of the biphenyltetracarboxylic acid anhydride is 75 mol % or more, and (ii) the content of the ester-containing tetracarboxylic acid anhydride is 15 to 80 mol %, and the content of the biphenyltetracarboxylic acid anhydride is 85 to 20 mol %.