Halogen-Free Resin Composition for Low Dielectric Circuit Laminates
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Solution Overview
Problem
Traditional halogen-free laminates for printed circuits face challenges in achieving low dielectric constant, low dielectric loss factor, low water absorption, high thermal resistance, and good flame retardancy while maintaining mechanical properties and processability, as existing solutions either compromise on thermal resistance or adhesion strength.
Innovation Solution
A halogen-free resin composition comprising dicyclopentadiene benzoxazine resin, epoxy resin, an active ester curing agent, and a phosphorus-containing flame retardant, which synergistically reduces dielectric constants, dielectric loss, water absorption, and enhances thermal resistance and mechanical properties without compromising adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If phenolic resin is used as epoxy curing agent to improve thermal resistance, then thermal resistance is improved, but dielectric property deteriorates
Solution Approach 1:
The patent extracts the problematic benzene ring structure from phenolic resin that causes poor dielectric properties, while retaining the desirable high thermal resistance. This is achieved by using alternative curing agents (aromatic carboxylic acid active esters, dicyclopentadiene benzoxazine resin, or their combinations) that do not introduce benzene rings into the cured network, thereby eliminating the source of dielectric deterioration while maintaining thermal resistance through proper crosslinking density.
Solution Approach 2:
The patent employs composite curing systems combining aromatic carboxylic acid active esters with dicyclopentadiene benzoxazine resin or other epoxy resins. This composite approach allows the active ester to provide low dielectric properties and high crosslinking density, while the benzoxazine resin contributes to thermal stability and flame retardancy, achieving synergistic effects that simultaneously improve both thermal resistance and dielectric properties.
2Ease of operation
If dicyandiamide is used as curing agent to improve processing operability, then processing operability is improved, but thermal decomposition temperature decreases
Solution Approach 1:
The patent changes the chemical structure parameters of the curing agent from dicyandiamide (which has weak C-N bonds) to aromatic carboxylic acid active esters and dicyclopentadiene benzoxazine resin. This parameter change replaces the weak C-N bonds with stronger C-O and C-C bonds in the cured network, thereby increasing thermal decomposition temperature while maintaining processing operability through the reactive nature of the active ester groups.
3Reliability
If active ester curing agent is used to reduce dielectric constant and dielectric loss, then dielectric property is improved, but adhesion force decreases
Solution Approach 1:
The patent introduces dicyclopentadiene benzoxazine resin as an intermediary substance that mediates between the active ester curing agent and the epoxy resin matrix. The benzoxazine resin provides polar groups and hydrogen bonding capabilities that enhance adhesion to substrates and reinforcement materials, while the active ester maintains low dielectric properties. This intermediary role allows the system to achieve both low dielectric constant and high adhesion force simultaneously.
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 low dielectric constant, low dielectric loss factor, high thermal resistance, high storage modulus, and excellent flame retardancy, meeting UL 94V-0 standards while maintaining good adhesion and processability, suitable for high-density interconnectors.
Implementation Method 1
curing a epoxy resin using an active ester curing agent
Implementation Method 2
phosphorus-containing flame retardant... excellent flame retardancy, meeting UL 94V-0 standards
Implementation Method 3
dicyclopentadiene benzoxazine resin... low dielectric constant, low dielectric loss factor
Data Source
AI summary
Disclosed is a halogen-free resin composition. The halogen-free resin composition comprises: (A) 10-60 parts by weight of dicyclopentadiene benzoxazine resin, (B) an epoxy resin, (C) an active ester curing agent and (D) a phosphorus-containing flame retardant, based on 100 parts by weight of the total amount of total organic solid matters of (A), (B), (C) and (D). A prepreg and a laminate which are prepared using the halogen-free resin composition have low dielectric constant, low dielectric loss factor, low water absorption, high dimensional stability, high thermal resistance and good flame retardancy, processability and chemical resistance.