Halogen-Free Resin Composition for Printed Wiring Boards
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Solution Overview
Problem
Existing resin compositions for printed wiring boards face challenges in achieving both flame retardancy and heat resistance without using halogen-based compounds, as nitrogen compounds can produce harmful nitrogen oxides and increasing phosphorus content decreases glass transition temperature.
Innovation Solution
A resin composition combining polyphenylene ether with a specific number average molecular weight, cyclophosphazene compounds, non-halogen-based epoxy resin, cyanate compounds, and fillers, such as silica, to enhance flame retardancy, heat resistance, and electrical characteristics while avoiding halogen-based compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-based compounds are used to achieve flame retardancy, then flame retardancy is improved, but harmful substances such as dioxin are generated during burning
Solution Approach 1:
The invention extracts and removes halogen-based compounds from the resin composition entirely, replacing them with non-halogen-based flame retardant compounds. This extraction eliminates the source of harmful substances like dioxin while maintaining the flame retardancy function through alternative chemical mechanisms.
Solution Approach 2:
The invention converts the harmful effect of halogen compounds into a beneficial non-halogen-based flame retardancy system. By using compounds containing phosphorus, nitrogen, or both in specific ratios, the system achieves effective flame suppression without generating toxic combustion products, turning a harmful approach into a beneficial one.
2Reliability
If phosphorus compound content is increased to achieve flame retardancy, then flame retardancy is improved, but glass transition temperature decreases
Solution Approach 1:
The invention changes the parameters of the flame retardant system by specifying precise compositional ratios: phosphorus content at 0.1-5 mass%, nitrogen content at 0.1-5 mass%, and their ratio P/N between 0.1-10. These parameter optimizations allow achieving flame retardancy with minimal impact on glass transition temperature, resolving the contradiction between flame suppression and heat resistance.
Solution Approach 2:
The invention creates a composite flame retardant system combining multiple compounds containing phosphorus, nitrogen, or both, along with a non-halogen-based epoxy resin and other components. This composite approach distributes the flame retardancy function across multiple substances, allowing lower individual phosphorus content while maintaining overall effectiveness, thus preserving heat resistance.
3Reliability
If nitrogen compound is used to achieve flame retardancy without halogen, then halogen-free flame retardancy is achieved, but harmful nitrogen oxides are produced
Solution Approach 1:
The invention optimizes the nitrogen content parameter to 0.1-5 mass% and controls the P/N ratio between 0.1-10, ensuring that nitrogen compounds are used in controlled amounts that minimize nitrogen oxide generation during combustion while maintaining flame retardancy effectiveness.
Solution Approach 2:
The invention balances the use of nitrogen-containing compounds by combining them with phosphorus-containing compounds in specific ratios. This combination converts the potentially harmful nitrogen oxide production into a more benign flame suppression mechanism where phosphorus and nitrogen work synergistically to reduce overall toxicity of combustion products.
Data Source
AI summary
A resin composition comprising a polyphenylene ether (A) having a number average molecular weight of 500 to 5000; a cyclophosphazene compound (B); a non-halogen-based epoxy resin (C); a cyanate compound (D); and a filler (E).