Modified Polyphenylene Ether for High-Frequency PCBs
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Solution Overview
Problem
Polyphenylene ethers face challenges in achieving sufficient heat resistance and moldability while maintaining excellent dielectric properties, particularly in high-frequency applications, due to their thermoplastic nature and high molecular weight, which can lead to molding defects in printed circuit boards.
Innovation Solution
A modified polyphenylene ether with an intrinsic viscosity of 0.03 to 0.12 dL/g, having 1.5 to 3 phenolic hydroxyl groups per molecule and not more than 5% high-molecular-weight components, is developed, allowing for improved reactivity, storage stability, and flow properties, and is used in conjunction with a heat-curing type curing agent to form a resin composition with enhanced moldability and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyphenylene ether with high molecular weight is used to maintain dielectric properties, then dielectric properties are improved, but moldability deteriorates due to high viscosity
Solution Approach 1:
The patent changes the molecular weight parameter of polyphenylene ether from high to low (number-average molecular weight of 1,000 to 7,000), which reduces viscosity and improves moldability while maintaining dielectric properties through the specific molecular structure with terminal vinylbenzyl groups
Solution Approach 2:
The patent creates a composite resin system by combining low-molecular-weight modified polyphenylene ether with thermosetting resin (epoxy resin, phenolic resin, or polyamide resin), achieving both good dielectric properties and moldability through the synergistic effect of the two resin types
2Reliability
If polyphenylene ether is used as thermoplastic resin, then dielectric properties are improved, but heat resistance deteriorates
Solution Approach 1:
The patent combines thermoplastic polyphenylene ether with thermosetting resin to create a composite material that exhibits both the excellent dielectric properties of polyphenylene ether and the high heat resistance of thermosetting resin, achieving Tg of 100°C or higher in the cured product
3Ease of manufacture
If low-molecular-weight polyphenylene ether is used to improve moldability, then viscosity is reduced, but curing reaction insufficiently progresses
Solution Approach 1:
The patent introduces vinylbenzyl groups at the terminal positions of polyphenylene ether molecules in advance, which serve as reactive sites for crosslinking with thermosetting resin, ensuring sufficient curing reaction progresses even with low-molecular-weight polyphenylene ether having number-average molecular weight of 1,000 to 7,000
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 modified polyphenylene ether composition achieves excellent dielectric properties, improved moldability, and increased heat resistance in cured products, reducing the occurrence of molding defects and enabling the production of high-reliability printed circuit boards.
Implementation Method 1
having an excellent reactivity that contributes to a curing reaction
Data Source
AI summary
A modified polyphenylene ether according to one aspect of the invention has an intrinsic viscosity, as measured in 25° C. methylene chloride, of from 0.03 to 0.12 dL/g, has on molecular ends thereof an average of 1.5 to 3 groups represented by formula (1) below per molecule, and includes not more than 5 mass % of a high-molecular-weight component having a molecular weight of 13,000 or more.In formula (1), R1 is a hydrogen atom or an alkyl group of 1 to 10 carbons, and R2 is an alkylene group of 1 to 10 carbons.