Phosphorus Flame Retardant Epoxy Resin for Carbon Fiber Composites
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Solution Overview
Problem
Epoxy carbon fiber composites lack effective flame retardancy, which restricts their use in applications requiring stringent fire resistance, and existing formulations struggle to balance cure speed, mechanical properties, and flame retardancy while maintaining low viscosity and tack-free properties for automated processing.
Innovation Solution
A non-halogenated, phosphorus-containing flame retardant agent is integrated into an oxazolidone-based epoxy resin composition, combined with a mold release agent, curing agent, and catalyst, to enhance the flammability performance and achieve the necessary cure speed, mechanical properties, and flame retardancy of carbon fiber-reinforced composites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen flame-retardant agents are added to epoxy carbon fiber composites, then flame retardancy is improved, but noxious gases are generated during combustion
Solution Approach 1:
The invention changes the chemical composition parameter of the flame retardant from halogen-based to phosphorus-based compounds, specifically using phosphorus-containing epoxy compounds and phosphorus-containing flame retardants. This parameter change eliminates the generation of noxious halogenated gases during combustion while maintaining effective flame retardancy through the phosphorus-based fire suppression mechanism
Solution Approach 2:
The invention employs phosphorus-containing compounds that decompose and consume themselves during the fire suppression process, forming protective char layers and releasing fire-inhibiting gases. These compounds are designed to be sacrificial, providing temporary protection during the critical fire exposure period without leaving persistent harmful residues
2Ease of manufacture
If the viscosity of matrix resin is reduced for automated processing, then ease of manufacture is improved, but impregnation of carbon fiber fabric becomes difficult
Solution Approach 1:
The invention modifies the viscosity parameter of the matrix resin by selecting specific epoxy compounds with appropriate molecular weight and structural characteristics. The chosen phosphorus-containing epoxy compounds provide optimal viscosity that balances flowability for automated processing with sufficient impregnation capability for carbon fiber fabrics
Solution Approach 2:
The invention creates a composite resin system combining phosphorus-containing epoxy compounds with flame retardant additives and curing agents. This composite formulation achieves synergistic effects where the base epoxy provides low viscosity for processing, while the flame retardant components contribute to fire resistance without significantly increasing viscosity
3Reliability
If flame-retardant agents are added to epoxy formulations, then flame retardancy is improved, but Tg and tack-free properties deteriorate
Solution Approach 1:
The invention optimizes the concentration parameters of flame retardant additives in the epoxy formulation. By carefully controlling the amount of phosphorus-containing flame retardant (typically 5-20 wt% of total resin), the formulation achieves adequate flame retardancy while minimizing the negative impact on glass transition temperature and tack-free surface properties
Solution Approach 2:
The invention introduces coupling agents or surface treatments as intermediaries between the flame retardant particles and the epoxy matrix. These intermediaries improve the interfacial adhesion and compatibility, preventing flame retardant additives from disrupting the polymer network formation and thus preserving Tg and surface properties
4Strength
If epoxy carbon fiber composites are made with traditional thermosets, then mechanical strength is achieved, but self-extinguishing property is lost
Solution Approach 1:
The invention converts the typically harmful effect of thermoset combustion (strong burning and dripping) into a beneficial self-extinguishing property through the incorporation of phosphorus-containing flame retardants. These additives promote char formation and release fire-inhibiting gases that suppress combustion, transforming the material from fire-prone to fire-resistant while preserving the mechanical advantages of thermoset composites
Data Source
AI summary
A flame retardant epoxy resin composition for preparing a flame retardant fiber composite including: (a) at least one epoxy resin; (b) at least one flame retardant agent for improving the flammability performance of carbon fiber-reinforced epoxy composites; (c) at least one mold release agent; (d) at least one curing agent; and (e) at least one catalyst; a prepreg prepared using the above epoxy resin composition; and a flame retardant fiber composite prepared using the above prepreg.