Halogen-Free Resin Composition for Millimeter-Wave Radar PCBs
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Solution Overview
Problem
Current printed wiring boards for high-frequency applications face challenges in achieving low dielectric constant and dissipation factor, heat resistance, and flame retardance while minimizing environmental impact, particularly for millimeter-wave radar systems.
Innovation Solution
A resin composition comprising a compound with a maleimide group, a divalent group with at least two imide bonds, and a saturated or unsaturated divalent hydrocarbon group, combined with a halogen-free flame retardant, such as phenol-based, phosphite-based, or thioether-based antioxidants, to create a resin layer-provided support, prepreg, laminate sheet, and multilayer printed wiring board with improved high-frequency properties and reduced environmental burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyphenylene ether and thermosetting resin are used concurrently to achieve low transmission loss, then high frequency properties are improved, but heat resistance and flame retardance are insufficient
Solution Approach 1:
The patent uses a composite resin system combining polyphenylene ether (PPE) with specific thermosetting resins (polyimide or bismaleimide) to achieve both low transmission loss and high heat resistance. The composite formulation allows the PPE to provide excellent high frequency properties while the thermosetting resin contributes heat resistance and flame retardance, resolving the contradiction between these two requirements.
Solution Approach 2:
The patent modifies the chemical composition parameters of the resin system by selecting specific thermosetting resins with high glass transition temperatures and appropriate curing agents. By adjusting the ratio and type of thermosetting resin (polyimide or bismaleimide) in the composite, the formulation achieves optimal balance between transmission loss characteristics and thermal performance.
2Reliability
If halogen-based flame retardants are used to achieve flame retardance, then flame resistance is improved, but environmental burden increases
Solution Approach 1:
The patent extracts and eliminates halogen-based flame retardants from the resin composition, replacing them with halogen-free alternatives. This removal of harmful substances maintains the flame retardant function while eliminating the environmental burden associated with halogen compounds, particularly in the context of millimeter-wave radar applications where environmental compliance is critical.
Solution Approach 2:
The patent employs halogen-free flame retardants that can be effectively incorporated into the thermosetting resin system without requiring complex additional processing. These alternative flame retardants provide sufficient flame protection for the application while being environmentally acceptable, replacing the need for persistent halogen-based solutions.
3Reliability
If polyphenylene ether and polybutadiene resin are combined to improve compatibility and heat resistance, then adhesive property and flame retardance are improved, but dielectric constant increases
Solution Approach 1:
The patent applies local quality control by carefully limiting the content of polybutadiene resin in the composite formulation. Rather than using polybutadiene extensively, the invention incorporates it in controlled amounts sufficient to provide the necessary adhesive properties and flame retardance, while minimizing its impact on the dielectric constant. This localized application of the polybutadiene component resolves the contradiction between adhesive improvement and dielectric performance.
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 resin composition achieves excellent high-frequency properties, heat resistance, and flame retardance, with reduced transmission loss and environmental impact, enabling the production of high-performance printed wiring boards for millimeter-wave radar systems without halogen-based compounds.
Implementation Method 1
a resin composition which contains a polyphenylene ether resin and a polybutadiene resin as a base and can exhibit improved compatibility, heat resistance, thermal expansion properties, adhesive property to a conductor, flame retardance, and the like as a semi-IPN is formed at the production stage
Implementation Method 2
a halogen-free flame retardant, such as phenol-based, phosphite-based, or thioether-based antioxidants
Data Source
Figure 1(a)~1(c)
Figure 2(p)~2(r)
Figure 3(a)~3(c)
AI summary
The present invention relates to a resin composition containing (A) a compound having a maleimide group, a divalent group having at least two imide bonds, and a saturated or unsaturated divalent hydrocarbon group and (B) a halogen-free flame retardant.