Ambient Curing of Epoxy Prepregs via Ammonia Flow
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Solution Overview
Problem
Current aerospace-grade composite material curing processes require high temperatures and pressures, making them expensive, limited in size, and complex, with tooling needing to withstand these conditions and match the coefficient of thermal expansion of prepregs.
Innovation Solution
Curing epoxy-containing prepreg composite materials at ambient temperature and pressure using an enclosed environment with a controlled delivery of ammonia-containing compounds, maintaining the prepreg at room temperature and atmospheric pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature and pressure are used for curing, then the curing reaction rate is improved, but the equipment cost and complexity increase
Solution Approach 1:
The patent changes the chemical parameters of the resin system by using low-viscosity epoxy resins and specific amine hardeners that enable effective curing at ambient temperature and pressure, eliminating the need for high-temperature and high-pressure equipment while maintaining acceptable curing reaction rates
Solution Approach 2:
The patent replaces the mechanical/thermal curing system (ovens and autoclaves requiring high temperature and pressure) with a chemical curing system using ammonia-containing compounds that achieve curing at ambient conditions, substituting mechanical energy with chemical reaction energy
2Reliability
If high temperature and pressure equipment is used, then the curing effectiveness is improved, but the production cost increases
Solution Approach 1:
The patent modifies the chemical composition parameters by selecting specific low-viscosity epoxy resins and amine hardeners with appropriate reactivity ratios, enabling effective curing at ambient temperature and pressure, thereby eliminating expensive specialized equipment while maintaining curing effectiveness
Solution Approach 2:
The patent employs consumable chemical agents (ammonia-containing compounds) that can be applied directly to the prepreg and allowed to evaporate or react, replacing expensive reusable equipment (autoclaves and ovens) with cheaper chemical systems
3Productivity
If high temperature curing is used, then the reaction rate is improved, but the tooling requirements become more stringent
Solution Approach 1:
The patent changes the temperature parameter from high-temperature curing (250-355°F) to ambient temperature curing, which eliminates the requirement for tooling to withstand high temperatures and match thermal expansion coefficients, greatly expanding tooling material options and availability
Solution Approach 2:
Instead of adapting tooling to withstand high temperatures and match thermal properties, the patent inverts the approach by using chemical curing at ambient temperature, allowing any material to serve as tooling since extreme thermal conditions are eliminated
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
Enables efficient and cost-effective curing of composite materials without the need for high temperatures and pressures, allowing for larger parts and reduced tooling complexity, while maintaining the quality of the cured composite.
Implementation Method 1
delivering a flow of an ammonia-containing compound to the enclosed environment to a predetermined concentration via the inlet; maintaining the flow of the ammonia-containing compound to the enclosed environment at the predetermined concentration for a predetermined duration, and curing the epoxy-containing prepreg assembly
Implementation Method 2
the ammonia-containing compound may be derived from, without limitation, any compound capable of generating volatile ammonia such as ammonia carbonate, or pure ammonia, such as that supplied under pressure from a compressed gas cylinder
Data Source
AI summary
Methods and systems and components made according to the methods and systems, are disclosed relating to improved curing methods for epoxy resin-containing composite prepreg materials, wherein the composite prepreg materials are exposed to a flow of ammonia-containing compounds to fully cure the composite prepreg materials at substantially ambient temperatures and pressures.