Semi-IPN Resin for Low-Loss PCBs
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Solution Overview
Problem
Existing resin compositions for printed circuit boards, particularly those using polyphenylene ether and thermosetting resins, face issues such as deteriorated dielectric properties, heat resistance, and peeling strength when used in high-frequency applications, especially with low profile metal foils, due to incompatibility and phase separation, leading to increased transmission loss and thermal expansion.
Innovation Solution
A thermosetting resin composition of a semi-IPN composite is developed, comprising a polyphenylene ether and a butadiene polymer, which are compatibilized and uncured, using a specific crosslinking agent like maleimide compounds to enhance dielectric properties, heat resistance, and peeling strength, allowing for effective use with low profile metal foils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyphenylene ether and thermosetting resin are combined to lower melting point and melt viscosity, then press molding temperature and pressure can be reduced, but dielectric properties deteriorate due to polar functional groups in the cured resin
Solution Approach 1:
The patent changes the chemical structure parameters of the thermosetting resin by using non-polar or low-polarity groups (such as phenyl, naphthyl, or fluoro groups) instead of traditional polar functional groups. This parameter change allows the cured resin to maintain excellent dielectric properties while still achieving the desired lowering of melting point and melt viscosity through the combination with polyphenylene ether.
Solution Approach 2:
The patent creates a composite resin system combining polyphenylene ether with specifically designed thermosetting resins that have non-polar or low-polarity functional groups. This composite material approach allows the system to benefit from both the processability improvements (lower melting point and viscosity) and maintain excellent dielectric properties, resolving the contradiction between ease of manufacture and reliability.
2Reliability
If fluorine-based resins are used to achieve low dielectric constant and low dielectric dissipation factor, then transmission loss is reduced, but melting temperature and melt viscosity increase requiring high temperature and pressure for press molding
Solution Approach 1:
The patent combines polyphenylene ether with thermosetting resins having non-polar or low-polarity groups to create a composite material that achieves both low transmission loss (excellent dielectric properties) and reduced processing requirements. The composite structure allows the polyphenylene ether to contribute to dielectric performance while the thermosetting component provides appropriate melting characteristics for press molding.
Solution Approach 2:
The patent changes the molecular structure parameters of the resin system by introducing thermosetting resins with specific non-polar or low-polarity functional groups, which modifies the melting temperature and melt viscosity parameters to suitable ranges for press molding while maintaining the low dielectric constant and dissipation factor needed for low transmission loss.
3Reliability
If polyphenylene ether is used for its excellent dielectric properties, then transmission loss is reduced, but thermal resistance is insufficient to withstand temperatures greater than its melting temperature
Solution Approach 1:
The patent utilizes the phase transition characteristics of polyphenylene ether by combining it with thermosetting resins. The thermosetting component provides a cured network structure that maintains dimensional stability and thermal resistance above the melting temperature of polyphenylene ether, while the polyphenylene ether phase provides excellent dielectric properties. This phase transition approach allows the material to withstand temperatures greater than 230-250°C while maintaining low transmission loss.
Solution Approach 2:
The patent creates a composite material system where polyphenylene ether is combined with thermosetting resins having non-polar or low-polarity groups. The composite structure allows the polyphenylene ether to contribute its excellent dielectric properties for low transmission loss, while the thermosetting matrix provides the necessary thermal resistance and dimensional stability at elevated temperatures.
4Strength
If conventional resin compositions are used with low profile metal foils, then peeling strength is insufficient due to incompatibility and phase separation, but using modified resins increases transmission loss
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by using thermosetting resins with non-polar or low-polarity functional groups that are compatible with polyphenylene ether. This parameter change eliminates phase separation and incompatibility issues, providing excellent adhesion to low profile metal foils while maintaining the low transmission loss characteristics of the polyphenylene ether-based system.
Solution Approach 2:
The patent creates a composite resin system that is specifically designed to be compatible with low profile metal foils. The combination of polyphenylene ether with thermosetting resins having non-polar or low-polarity groups provides both the adhesion needed for strong peeling strength and the dielectric properties needed for low transmission loss, resolving the contradiction between strength and reliability.
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 semi-IPN composite resin composition achieves excellent dielectric properties, reduced transmission loss, and improved heat resistance and peeling strength, enabling its use in high-frequency applications with low profile metal foils, thus addressing the limitations of previous resin compositions.
Implementation Method 1
a prepolymer formed from (B) a butadiene polymer which is not chemically modified, has a crosslinked structure
Implementation Method 2
excellent dielectric properties, reduced transmission loss
Data Source
AI summary
Provided is a thermosetting resin composition which can be used for the production of printed circuit boards, having good dielectric properties in high frequency bands so that transmission loss can be significantly lowered, having excellent heat resistance after moisture absorption and thermal expansion properties, and satisfying peeling strength between the resin composition and metal foil. The present invention relates to a thermosetting resin composition comprising a polyphenylene ether-modified butadiene prepolymer comprising a polyphenylene ether (A) and a butadiene polymer (B'), characterized in that the component (A) has a number average molecular weight in the range of 7000 to 30000; the component (B') comprises 40% or more of a unit derived from a 1,2-butadiene unit having a 1,2-vinyl group in a side chain; the component (B') is not a modified polybutadiene in which the 1,2-vinyl group in the side chain, or one or both of the terminals in the molecule of the component (B') is/are chemically modified by converting into epoxy, glycol, phenol, maleic acid, (meth)acryl, or urethane; and the component (B') has a cross-linked structure; and a resin varnish, a prepreg and a metal clad laminated board using the same.