Halogen-Free Epoxy Resin Composition for Low Dielectric Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional epoxy resin compositions, such as FR-4, face challenges in achieving a balance between high glass transition temperature, low dielectric loss, and stable dielectric properties at high frequencies, while also meeting the requirements of heat resistance and moisture resistance, especially with the transition to lead-free processes.
Innovation Solution
A halogen-free epoxy resin composition is developed using a combination of DOPO modified curing agents, benzoxazine resin, active ester compounds, and specific flame retardants, which includes 100 parts of epoxy resin, 10-30 parts of DOPO modified curing agent, 1-10 parts of benzoxazine resin, 60-90 parts of active ester, 20-50 parts of flame retardant, and 0.5-10 parts of curing accelerator, to achieve superior heat resistance, low dielectric loss, and high flame retardancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If novolac resins are used as curing agents to improve heat resistance, then glass transition temperature increases, but dielectric loss values increase
Solution Approach 1:
The patent changes the chemical structure parameters of the curing agent from conventional novolac to active esters with specific molecular configurations. This structural parameter change enables achieving both high glass transition temperature (170-200°C) and low dielectric loss (Df < 0.01 at 10 GHz) by selecting esters with aromatic rings and specific functional groups that provide thermal stability without excessive dielectric loss
Solution Approach 2:
The patent creates a composite curing system using combinations of different active ester types (benzoate, salicylate, phenylacetate esters) along with DOPO-modified curing agents. This composite approach allows balancing heat resistance and dielectric properties by combining the thermal stability of aromatic esters with the low dielectric loss characteristics of DOPO structures
2Strength
If conventional FR-4 materials are used to maintain mechanical strength, then structural stability is maintained, but dielectric properties deteriorate at high frequencies
Solution Approach 1:
The patent changes the resin matrix composition parameters by replacing conventional epoxy-novolac systems with epoxy-active ester-DOPO composite systems. This chemical composition change reduces dielectric loss (Df < 0.01 at 10 GHz) while maintaining mechanical strength through the cross-linking structures formed by active ester curing and DOPO modification
Solution Approach 2:
The patent develops a composite material system combining epoxy resin with active ester curing agents and DOPO-modified compounds. This composite structure achieves both mechanical integrity (tensile strength > 50 MPa) and superior dielectric properties (Dk ≈ 3.8, Df < 0.01) by integrating multiple functional components with complementary properties
3Adaptability or versatility
If lead-free processes are implemented to improve environmental compatibility, then manufacturing compliance improves, but heat resistance requirements become more difficult to meet
Solution Approach 1:
The patent changes the thermal stability parameters of the curing system by introducing DOPO-modified curing agents with phosphorus-containing structures. These structures provide inherent flame retardancy and thermal stability (maintaining mechanical properties at temperatures up to 200°C) while being compatible with lead-free soldering processes that require elevated temperatures
Solution Approach 2:
The patent converts the potential weakness of lead-free processes (higher operating temperatures) into an advantage by incorporating flame retardant DOPO structures that enhance heat resistance. The phosphorus-containing curing agents create a char-forming network that improves thermal stability and flame retardancy, turning the thermal challenge of lead-free processing into a opportunity for enhanced performance
Data Source
AI summary
The present invention discloses a halogen-free epoxy resin composition having low dielectric loss, comprises: (A) 100 parts by weight of an epoxy resin; (B) 10-30 parts by weight of a DOPO modified curing agent; (C) 1-10 parts by weight of benzoxazine resin; (D) 60-90 parts by weight of an active ester compound; (E) 20-50 parts by weight of a flame retardant; and (F) 0.5-10 parts by weight of a curing accelerator. The halogen-free epoxy resin composition uses active ester as a curing agent of the epoxy resin to ensure that the hardening product has characteristics such as low dielectric constant (Dk), low dielectric loss (Df), high heat resistance, low water absorption, flame retardant and halogen-free. The halogen-free epoxy resin composition of the present invention is used for manufacturing semi-cured prepregs or resin-coated films, and is applied toward manufacturing metal clad laminates and printed circuit boards.