Epoxy Resin System for Rapid Curing Carbon Fiber Composites
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Solution Overview
Problem
Epoxy resin systems used in fiber-reinforced composites face challenges with long in-mold curing times, rapid viscosity increase, and the need for high mold temperatures, which hinder production efficiency and competitiveness with metal parts, while also requiring a stable dye for aesthetic appeal in carbon fiber composites.
Innovation Solution
A curable epoxy resin system comprising polyglycidyl ethers of polyphenol with a polyethylene tetraamine mixture hardener and triethylene diamine, combined with an internal mold release agent and a dye solution, such as Mordant Black 17, to achieve rapid curing, low initial viscosity, and high glass transition temperature, while maintaining stability and solubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the resin system is formulated to cure rapidly, then the production time is reduced, but the viscosity increases rapidly making it difficult to penetrate between fibers
Solution Approach 1:
The resin system is pre-formulated with a specific epoxy resin and amine hardener combination that maintains low viscosity during the critical mold-filling phase, allowing complete fiber penetration before the curing reaction accelerates and increases viscosity
Solution Approach 2:
The patent utilizes the specific chemical parameters of the epoxy resin and amine hardener to control the viscosity-temperature-time relationship, maintaining low viscosity at processing temperatures while achieving rapid cure at service temperatures
2Ease of operation
If the fibers are pre-heated to improve resin flow, then the mold-filling is improved, but the resin reacts very rapidly at contact points causing premature curing
Solution Approach 1:
The resin system's chemical composition parameters are optimized to maintain stability at elevated temperatures during mold-filling, preventing premature reaction even when contacting pre-heated fibers, while ensuring rapid cure occurs uniformly after mold closure
3Manufacturing precision
If increasing operating pressures are used to overcome rapid viscosity build, then the resin can flow better, but the reinforcing fibers are moved around causing inconsistent properties
Solution Approach 1:
The resin system's viscosity parameters are controlled through specific epoxy resin and hardener selection to remain low throughout the mold-filling process, eliminating the need for high operating pressures that would disturb fiber placement, while maintaining rapid cure characteristics
4Strength
If epoxy resin systems are used to achieve high strength and stiffness, then the composite properties are improved, but the in-mold curing times are long reducing production efficiency
Solution Approach 1:
The patent employs a specific epoxy resin with particular molecular weight and structural parameters combined with an amine hardener to achieve both high ultimate strength properties and reduced curing time, optimizing the balance between performance and productivity
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
This system enables short cycle times, high glass transition temperatures, and stable dye performance, improving the production efficiency and aesthetic appeal of carbon fiber composites without compromising curing characteristics or reactivity.
Implementation Method 1
A mixture of an epoxy resin component and a hardener is then injected into the mold, where it flows around and between the fibers, fills the cavity and cures to form the composite
Implementation Method 2
low molecular weight, low viscosity precursors are used as starting materials. The low viscosity is an important attribute because it allows the resin system to penetrate easily between and wet out the fibers
Implementation Method 3
If the fibers are pre-heated, which is often the case, the resin system can react very rapidly at points of contact with the heated fibers
Implementation Method 4
the glass transition temperature of the cured resin. For curing epoxy resin systems, the glass transition temperature increases as the polymerization reactions proceed
Data Source
AI summary
A two-component curable epoxy resin system including a dye solution. The resin system includes an epoxy resin component containing at least 80% by weight of a polyglycidyl ether of a polyphenol. The system also includes a hardener mixture containing mainly polyethylene tetraamines. The system includes triethylene diamine in specific amounts as a catalyst. The system has beneficial curing characteristics with desired color that make it useful for producing fiber-reinforced composites in a resin transfer molding process.