Crosslinkable Silphenylene Polymer Binders for Low-Loss RF Laminates
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Solution Overview
Problem
Existing polyorganosiloxane binders for radiofrequency applications suffer from high dielectric loss factors, poor adhesion, and mechanical instability, limiting their suitability for copper-faced laminates and circuit boards, while existing silphenylene polymers are costly and complex to produce, retaining Si—O—Si units that hinder low dielectric loss factors.
Innovation Solution
Development of silphenylene polymers with a random composition and minimal Si—O bonds, crosslinkable by radical polymerization, offering excellent heat resistance, weathering stability, and flame retardance, with dielectric loss factors below 0.0030, suitable for metal-faced laminates and circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyorganosiloxanes are used as binders, then heat resistance and flame retardance are improved, but dielectric loss factor increases
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating silphenylene units with specific aromatic rings and silicon-oxygen-silicon bond angles that reduce the electronegativity difference effect, thereby maintaining low dielectric loss factors while preserving heat resistance properties
Solution Approach 2:
The invention creates a composite polymer structure combining silphenylene units with organic polymer components, achieving a synergistic effect that provides both low dielectric loss factors suitable for RF applications and the heat resistance characteristics of polyorganosiloxanes
2Object-affected harmful factors
If polydiorganosiloxanes are used, then dielectric loss factor is reduced, but mechanical strength and adhesion deteriorate
Solution Approach 1:
The patent formulates a composite binder system combining silphenylene polymers with organic polymers such as polyphenylene ethers, where the organic component provides mechanical strength and adhesion while the silphenylene component maintains low dielectric loss factors
Solution Approach 2:
The invention introduces specific functional groups and aromatic structures at localized positions within the polymer chain to enhance mechanical properties and adhesion without affecting the overall low dielectric loss characteristic of the silphenylene backbone
3Strength
If conventional epoxy resins are used, then adhesion and mechanical properties are improved, but dielectric loss factor increases
Solution Approach 1:
The patent modifies the chemical structure by using silphenylene units with specific aromatic substitutions and silicon bonding configurations that reduce polarity and dielectric loss, while maintaining adhesion through controlled functional group incorporation
4Object-affected harmful factors
If polydimethylsiloxanes are used, then dielectric loss factor is reduced, but workability and viscosity deteriorate
Solution Approach 1:
The invention adjusts the molecular weight, chain flexibility, and aromatic content parameters of the silphenylene polymer to achieve an optimal viscosity range that provides both low dielectric loss factors and good workability for laminate production processes
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 silphenylene polymers provide improved dielectric properties, mechanical stability, and compatibility with organic polymers, enabling the production of dimensionally stable moldings and prepregs suitable for radiofrequency applications.
Implementation Method 1
Candidate binders for radiofrequency applications include polyorganosiloxanes which possess a three-dimensional framework structure and which, furthermore, can be crosslinked chemically to form thermosets... through crosslinking, such as the radical polymerization of the binders used that is employed preferably for the production of metal-faced laminates
Data Source
AI summary
Silphenylene polymers along with processes for producing and uses for the same. Where the Silphenylene polymers have the formula (I)RaR1bSi[Y[(SiR2cR3d)e]f]gYSiRaR1b (I).At least one olefinically or acetylenically unsaturated radical R, R1, R2 or R3 must be present per silphenylene polymer of the formula (I). Where the sum of all organic radicals bonded to Si atoms through an oxygen atom, based on the sum of all Si-bonded radicals R, R1, R2 and R3 as 100 mol %, must not be more than 10 mol %. Where based on all bridging radicals Y as 100 mol %, at least 55 mol % of radicals Y are a di- to dodecavalent aromatic, alkylaromatic and cycloalkylaromatic radical.