Fluorene-Containing Bismaleimide Resin for High-Frequency PCBs
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Solution Overview
Problem
Current insulating materials for multi-layered printed-wiring boards, such as epoxy resin compositions and bismaleimide resins, fail to meet the requirements for high-frequency applications due to insufficient dielectric properties and heat resistance, particularly at high-frequency bands like 5G, and exhibit issues with glass-transition temperature and curability.
Innovation Solution
A heat-curable fluorene-containing bismaleimide resin composition with a specific bismaleimide compound and reaction accelerator, which includes a fluorene frame and a radical or anionic polymerization catalyst, is developed to achieve improved dielectric properties and heat resistance, with a glass-transition temperature of 200°C or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy resin compositions or conventional bismaleimide resins are used for insulating materials, then basic electrical insulation is achieved, but dielectric properties are insufficient for high-frequency applications
Solution Approach 1:
The patent changes the chemical structure parameters of the bismaleimide resin by introducing fluorene frames and specific organic groups (A and B with defined carbon atom ranges) to optimize dielectric properties for high-frequency applications while maintaining heat resistance
Solution Approach 2:
The invention creates a composite resin system combining fluorene-containing bismaleimide compounds with specific curing agents and reaction accelerators to achieve synergistic effects that improve both dielectric properties and heat resistance simultaneously
2Reliability
If long-chain alkyl group-containing bismaleimide resin is used to improve dielectric properties, then dielectric tangent is reduced, but glass-transition temperature cannot reach 100°C or higher
Solution Approach 1:
The patent changes the molecular structure by incorporating rigid fluorene frames and aromatic groups into the bismaleimide backbone, which increases glass-transition temperature while the specific structural parameters (groups A and B with defined carbon ranges) maintain low dielectric tangent through controlled molecular packing and reduced polarity
Solution Approach 2:
The invention combines fluorene-containing bismaleimide resin with complementary curing agents and reaction accelerators to create a crosslinked network that achieves both high glass-transition temperature (≥100°C) and low dielectric tangent through synergistic molecular interactions
3Temperature
If fluorene-containing imide oligomer is used as heat resistant plasticizer, then heat resistance is improved, but heat curability is lost
Solution Approach 1:
The patent changes the chemical functionality of fluorene-containing compounds by designing bismaleimide structures with curable functional groups (maleimide rings) while incorporating fluorene frames for heat resistance, and selects curing agents and reaction accelerators with appropriate reactivity parameters to restore heat curability
Solution Approach 2:
The invention introduces reaction accelerators as intermediary substances that mediate between the fluorene-containing bismaleimide resin and curing agents, enabling heat curability to proceed at practical rates while preserving the heat resistance provided by the fluorene structure
4Temperature
If fluorene frame is introduced to improve heat resistance, then glass-transition temperature increases, but dielectric properties may deteriorate
Solution Approach 1:
The patent optimizes the structural parameters of the fluorene-containing bismaleimide compound by controlling the types and positions of organic groups A and B (with specific carbon atom ranges 4-200 and 2-200 respectively) to balance the competing requirements of high glass-transition temperature and excellent dielectric properties through controlled molecular polarity and packing density
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 heat-curable bismaleimide resin composition maintains excellent dielectric properties while achieving a significantly higher glass-transition temperature, making it suitable for high-frequency applications and providing enhanced heat resistance and reliability.
Implementation Method 1
the reaction accelerator as the component (B) is a radical polymerization initiating catalyst
Implementation Method 2
or an anionic polymerization initiating catalyst containing one or more kinds of atoms selected from nitrogen atoms and phosphorus atoms
Implementation Method 3
a cured product of the heat-curable bismaleimide resin composition has a glass-transition temperature of not lower than 200°C
Data Source
AI summary
Provided is a resin composition capable of being turned into a cured product having a high glass-transition temperature and excellent dielectric properties as well. The resin composition is a heat-curable bismaleimide resin composition containing:(A) a bismaleimide compound represented by the following formula (1)wherein A independently represents a tetravalent organic group having 4 to 200 carbon atoms, B independently represents a divalent organic group having 2 to 200 carbon atoms, n is 2 to 100, andwherein A and/or B has therein a fluorene frame represented by the following formula (2)wherein each of R1, R2, R3 and R4 independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a (hetero)aryl group having 4 to 10 carbon atoms, a hydroxyl group, an alkoxy group, a halogeno group, an amino group, or a sulfenyl group; and(B) a reaction accelerator.