Phosphorus Epoxy Resin for High Tg Circuit Boards
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional phosphorus-containing epoxy resins fail to provide sufficient heat resistance and tracking resistance while maintaining flame retardancy, especially in thick laminated plates used in electronic circuit boards, with existing technologies unable to achieve a glass transition temperature (Tg) of 200°C or higher and adequate tracking resistance.
Innovation Solution
A phosphorus-containing epoxy resin composition is developed using a novolac epoxy resin with a specific molecular weight distribution and average number of functional groups, combined with a phosphorus compound, to achieve a Tg of 200°C or higher and improved flame retardancy and tracking resistance, by optimizing the ratio of trinuclear bodies to hepta or higher nuclear bodies and the average number of functional groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a phosphorus compound is reacted with a multifunctional epoxy resin to achieve flame retardancy, then flame retardancy is improved, but heat resistance (Tg) is insufficient to reach 200°C or higher
Solution Approach 1:
The patent changes the molecular weight distribution parameters of the novolac epoxy resin, specifically controlling the ratio of trinuclear bodies to hepta or higher nuclear bodies and the average number of functional groups, to achieve both flame retardancy and high Tg of 200°C or higher
Solution Approach 2:
The patent creates a composite epoxy resin system by combining phosphorus-containing compounds with specifically designed novolac epoxy resins, achieving synergistic effects that provide both flame retardancy and high heat resistance
2Object-affected harmful factors
If a phosphorus-containing epoxy resin is used to achieve flame retardancy, then flame retardancy is improved, but tracking resistance is insufficient
Solution Approach 1:
The patent optimizes the phosphorus content within a specific range (0.5-2.0 mass%) and controls the molecular weight distribution parameters to achieve both flame retardancy and adequate tracking resistance
3Object-affected harmful factors
If the phosphorus content is increased to maintain flame retardancy in thick laminated plates, then flame retardancy is improved, but heat resistance and tracking resistance deteriorate
Solution Approach 1:
The patent identifies an optimal phosphorus content range (0.5-2.0 mass%) that provides sufficient flame retardancy while maintaining heat resistance and tracking resistance, avoiding the drawbacks of both low and excessive phosphorus content
Solution Approach 2:
The patent applies different molecular weight distribution characteristics to different aspects of the resin system, with trinuclear bodies contributing to flame retardancy and hepta or higher nuclear bodies contributing to heat resistance and tracking resistance
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 composition achieves high heat resistance with a Tg of 200°C or higher, maintains V-0 level flame retardancy, and enhances tracking resistance, outperforming conventional phosphorus-containing epoxy resins in electronic circuit board applications.
Implementation Method 1
a phosphorus-containing epoxy resin composition which contains a phosphorus-containing epoxy resin and a curing agent
Implementation Method 2
phosphorus-containing epoxy resin having flame retardancy such as a sealing material
Data Source
Figure 1~2
AI summary
An object is to provide an epoxy resin composition which exhibits excellent tracking resistance and additionally has excellent heat resistance with a Tg of 200°C or higher and flame retardancy. Provided is an epoxy resin composition which contains a phosphorus-containing epoxy resin and a curing agent and has a phosphorus content of within a range of 1.0 to 1.8%, wherein the phosphorus-containing epoxy resin has a ratio (L/H) of 0.6 to 4.0 of the content of trinuclear bodies (L) to the content of hepta or higher nuclear bodies (H) measured by GPC, and is a product obtained from a novolac epoxy resin having an average number of functional groups (Mn/E) of 3.8 to 4.8 and a phosphorus compound represented by the following general formula (1) and/or general formula (2):