Polyisocyanurate Prepregs for High-Frequency PCB Applications
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Solution Overview
Problem
Current prepregs based on epoxy resins have storage stability issues at room temperature and do not meet the dielectric property requirements for high-frequency signal transmission and heat resistance for applications like printed circuit boards, while polyurethane-based prepregs have inadequate dielectric properties and low heat resistance.
Innovation Solution
A polymerizable composition comprising a combination of aliphatic, cycloaliphatic, and aromatic polyisocyanates with a molar excess of isocyanate groups, allowing for a dual curing mechanism to achieve storage-stable semi-finished products and fully cured materials with improved dielectric properties and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If epoxy resin compositions are used for prepregs, then curability by heating is achieved, but storage stability at room temperature deteriorates due to curing proceeding at normal temperature
Solution Approach 1:
The patent changes the chemical composition parameters of the resin system by combining polyisocyanate, polyol, and polyester components in specific ratios. This creates a resin composition that remains stable at room temperature during storage but can be cured at elevated temperatures (100-200°C) when needed, thus resolving the contradiction between storage stability and curability.
2Stability of the object's composition
If polyurethane-based prepregs are used, then storage stability at room temperature is improved, but dielectric properties deteriorate due to higher dielectric constants and dissipation factors
Solution Approach 1:
The patent creates a composite resin system combining polyisocyanate, polyol, and polyester components that work together to achieve both storage stability and acceptable dielectric properties. The specific formulation balances the polar urethane groups for stability while controlling the overall dielectric constant and dissipation factor for high-frequency applications.
3Stability of the object's composition
If polyurethane-based prepregs are used, then storage stability at room temperature is improved, but heat resistance deteriorates due to low glass transition temperature
Solution Approach 1:
The patent modifies the resin composition parameters by selecting specific polyol and polyester components and controlling their molecular weights and functional groups. This formulation approach raises the glass transition temperature to above 150°C while preserving room-temperature storage stability, thus resolving the contradiction between storage stability and heat resistance.
4Stability of the object's composition
If dual curing mechanism is implemented, then curability and storage stability are improved, but manufacturing complexity increases due to multiple curing steps
Solution Approach 1:
The patent segments the curing process into two distinct stages: a first curing step that forms the initial crosslinked structure for storage stability, and a second curing step that completes the crosslinking for final performance. This segmentation allows each step to be optimized independently, managing the complexity through structured process division.
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 dual curing mechanism enables prepregs that are storage-stable at room temperature, have low dielectric properties, and achieve high glass transition temperatures, suitable for high-frequency applications and enhanced heat resistance.
Implementation Method 1
a dual curing mechanism which allows the manufacture of polyisocyanurate plastics in two different curing steps
Implementation Method 2
comprising a combination of aliphatic, cycloaliphatic, and aromatic polyisocyanates with a molar excess of isocyanate groups, allowing for a dual curing mechanism
Data Source
AI summary
The present invention relates to polyisocyanate compositions comprising two different types of polyisocyanate, their use in the manufacture of prepregs and polyisocyanurate composited made from said prepregs.