Halogen-Free Flame-Retardant Resin Composition for PCBs
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Solution Overview
Problem
Current halogen-free flame retardant resin compositions for printed circuit boards face challenges in achieving high thermal resistance and processability while maintaining low brittleness and water absorption, particularly when using phosphorus-modified epoxy resins and dihydrobenzoxazine rings, as they often result in limited thermal resistance and unsatisfactory processability.
Innovation Solution
A halogen-free flame retardant resin composition comprising a mixture of phenoxyphosphazene compounds and dihydrobenzoxazine rings, combined with an epoxy resin and phenolic resin, using an aromatic amine curing agent to enhance synergistic curing and improve glass transition temperature, thermal resistance, and processability, while maintaining low halogen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If phosphorus-modified epoxy resin is used to achieve flame retardancy, then flame retardant performance is improved, but water absorption increases and thermal resistance decreases
Solution Approach 1:
The patent uses a composite resin system combining benzoxazine resin (providing flame retardancy and low water absorption) with epoxy resin (providing toughness and processability), cured with both phenolic resin and amine curing agents. This composite approach achieves flame retardancy without the drawbacks of phosphorus-modified epoxy resin, as the benzoxazine resin inherently provides flame resistance while the epoxy component maintains mechanical properties.
2Object-affected harmful factors
If a large amount of dihydrobenzoxazine ring compounds is added to improve flame retardancy, then flame retardant performance is improved, but brittleness increases
Solution Approach 1:
The patent optimizes the ratio of dihydrobenzoxazine ring compounds to other resin components and curing agents, finding the balance point where flame retardancy is maximized while brittleness is controlled. By adjusting composition parameters and curing conditions, the patent achieves both flame resistance and acceptable mechanical properties without excessive brittleness.
Solution Approach 2:
The patent combines dihydrobenzoxazine ring compounds with epoxy resin and uses dual curing agents (phenolic resin and amine) to create a composite system that balances flame retardancy and mechanical properties. The epoxy component and amine curing agent help reduce the brittleness inherent in high concentrations of dihydrobenzoxazine compounds.
3Temperature
If phenolic resin and amine curing agent are used together for synergistic curing, then glass transition temperature and thermal resistance are improved, but processability becomes more difficult
Solution Approach 1:
The patent uses imidazole compound as a curing accelerator to initiate and speed up the curing reaction before the resin fully sets. This preliminary action allows for adequate processing time during manufacturing while still achieving the high glass transition temperature and thermal resistance characteristic of dual-curing systems. The accelerator ensures complete curing without requiring excessively long processing times.
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 solution significantly improves flame retardancy, thermal resistance, and processability of the resin composition, reducing brittleness and water absorption, and achieving high glass transition temperatures, making it suitable for mass production and meeting environmental standards.
Implementation Method 1
using an aromatic amine curing agent to enhance synergistic curing and improve glass transition temperature, thermal resistance, and processability
Implementation Method 2
A halogen-free flame retardant resin composition comprising a mixture of phenoxyphosphazene compounds and dihydrobenzoxazine rings
Data Source
AI summary
The present invention relates to a halogen-free flame retardant resin composition, according to parts by weight, the resin composition comprises:(A) a mixture of phenoxyphosphazene compound (A1) and compound (A2) having dihydrobenzoxazine ring: 45-90 parts by weight, and the weight ratio of the phenoxyphosphazene compound (A1) and the compound(A2) having dihydrobenzoxazine ring is between 1:25-1:2; (B) an epoxy resin with epoxy equivalent of 500 -2000: 10-45 parts by weight; (C) a phenolic resin: 10-25 parts by weight, and (D) an amine curing agent: 0.5-10 parts by weight. The prepreg, laminate, metal-clad laminate for printed circuit prepared using the halogen-free flame retardant resin composition, have the advantages of high glass transition temperature (Tg), high thermal resistance, low dielectric dissipation factor, low water absorption as well as low C.T.E.