Vinyl Aromatic Copolymer Resin for High-Frequency PCBs
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Solution Overview
Problem
Current copper clad laminates face challenges with high dielectric loss tangent, brittleness, and insufficient heat and humidity resistance, making them unsuitable for high-frequency and high-multilayer printed circuit boards.
Innovation Solution
A thermosetting resin composition comprising a solvent-soluble polyfunctional vinyl aromatic copolymer and a vinyl-containing organosilicon resin, which provides high crosslinking density and improved toughness, dielectric properties, and resistance to heat and humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyfunctional vinyl aromatic copolymer is used to achieve low dielectric loss tangent and good fluidity, then dielectric properties are improved, but brittleness increases and heat resistance becomes insufficient
Solution Approach 1:
The patent combines polyfunctional vinyl aromatic copolymer with heat-resistant resin (such as polyphenylene ether or bismaleimide) to create a composite resin composition. This composite approach allows the material to inherit the low dielectric loss tangent and good fluidity from the vinyl aromatic copolymer while gaining heat resistance and reduced brittleness from the heat-resistant resin component.
Solution Approach 2:
The patent optimizes the molecular weight parameters of the polyfunctional vinyl aromatic copolymer, specifically controlling the number average molecular weight (Mn) to be 5,000-50,000 and weight average molecular weight (Mw) to be 50,000-200,000, with Mw/Mn ratio of 5-20. This parameter optimization balances the fluidity, dielectric properties, and mechanical characteristics including brittleness and heat resistance.
2Strength
If thermoplastic resin is added to improve toughness, then brittleness is reduced, but glass transition temperature decreases and phase separation occurs
Solution Approach 1:
Instead of using thermoplastic resins that cause long-term compatibility issues, the patent employs a thermosetting resin system that cures to form a crosslinked network. This approach provides toughness without the phase separation and glass transition temperature degradation associated with thermoplastic additions, as the crosslinked structure maintains thermal stability.
Solution Approach 2:
The patent carefully controls the functional group content and molecular weight of the polyfunctional vinyl aromatic copolymer to achieve optimal toughness without requiring thermoplastic resin addition. By controlling the vinyl aromatic compound content at 20-100 mol% and optimizing crosslinking density, the material achieves adequate toughness while maintaining high glass transition temperature.
3Temperature
If high crosslinking density is achieved to improve heat resistance, then heat resistance is improved, but brittleness increases
Solution Approach 1:
The patent optimizes the crosslinking density by controlling the functional group content (0.5-5 mmol/g) and molecular weight parameters of the polyfunctional vinyl aromatic copolymer. This balanced approach achieves sufficient heat resistance through moderate crosslinking while avoiding excessive brittleness that would result from very high crosslinking density.
Solution Approach 2:
The patent uses a composite resin system combining polyfunctional vinyl aromatic copolymer with heat-resistant resin, where the heat-resistant resin component provides thermal stability and the vinyl aromatic copolymer provides crosslinking. This composite approach achieves heat resistance without the extreme brittleness that would result from high crosslinking density alone.
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 enhances the brittleness of the polyfunctional vinyl aromatic copolymer, improves drilling processability, and maintains high glass transition temperature, low water absorption, and excellent dielectric properties, making it suitable for high-frequency and high-speed printed circuit boards.
Implementation Method 1
the vinyl group-containing organosilicon resin is used as a crosslinking agent of the soluble polyfunctional vinyl aromatic copolymer, and the resin composition has a high crosslinking density after curing
Implementation Method 2
the resin composition has a high crosslinking density after curing
Data Source
AI summary
A thermosetting resin composition and a prepreg and a metal foil-covered laminate made using same, the thermosetting resin composition comprising component (A): a solvent-soluble polyfunctional vinyl aromatic copolymer, the copolymer being a poly-functional vinyl aromatic copolymer having a stoctoal unit derived from monomers comprising divinyl aromatic compound (a) and ethyl vinyl aromatic compound (b); and component (B): a vinyl-containing organic silicone resin. The prepreg and metal foil-covered laminate made from the thermosetting resin composition have good toughness, and maintain a high glass transition temperature, a low water absorption, dielectric properties and humidity resistance, being suitable for the field of high-frequency and high-speed printed circuit boards and the processing of multilayer printed circuit boards.