Encapsulated Catalyst for Aerospace Resin Curing
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Solution Overview
Problem
Epoxy resin-based adhesive systems face limitations in manufacturing flexibility due to the relationship between work life and cure time, requiring heat to activate catalysts for rapid curing, which is impractical and costly in large-scale aerospace manufacturing, and result in inefficient production and increased waste.
Innovation Solution
Encapsulating catalysts within shells that release upon exposure to predetermined temperature and pressure, allowing for on-demand curing of epoxy and acrylate resin-based adhesives, maintaining adhesive tack at room temperature and enabling faster curing at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If catalyst is added to accelerate epoxy-amine reaction at elevated temperature, then cure rate is improved, but work life at room temperature is reduced
Solution Approach 1:
The catalyst is segmented into discrete microcapsules dispersed throughout the resin system. Each microcapsule contains encapsulated catalyst that remains isolated until triggered by heat, at which point the capsules rupture and release the catalyst locally to accelerate curing.
Solution Approach 2:
The catalyst is pre-encapsulated in heat-sensitive microcapsules and mixed with the resin system in advance. The encapsulation prevents premature catalyst release, allowing the resin to maintain long work life at room temperature while being primed for rapid curing when heated.
2Productivity
If heat is applied to activate catalyst for rapid curing, then productivity is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The resin system self-regulates its curing process through the heat-sensitive microcapsules. When the resin is applied and exposed to ambient or slightly elevated temperatures, the microcapsules automatically rupture at their predetermined temperature threshold, releasing the catalyst to accelerate curing without requiring external heating equipment or complex thermal control systems.
Solution Approach 2:
The curing behavior of the resin system is changed by incorporating heat-sensitive microcapsules with specific rupture temperatures. This allows the system to transition from slow room-temperature curing to accelerated curing simply by changing the temperature parameter, eliminating the need for complex heating equipment while maintaining productivity.
3Duration of action of moving object
If catalyst is segregated from resin at room temperature, then work life is extended, but catalyst dispersion at elevated temperature becomes challenging
Solution Approach 1:
The microcapsule shell acts as an intermediary carrier that holds the catalyst in a dispersed state within the resin system. The capsules prevent catalyst aggregation at room temperature while being designed to rupture at elevated temperatures, automatically achieving catalyst dispersion when needed without requiring separate dispersion steps.
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 approach extends the work life of adhesives, reduces production inefficiencies, and eliminates the need for refrigerated storage, allowing for longer assembly times and reduced waste, while enabling faster production of composite parts with minimal impact on final product performance.
Implementation Method 1
the shell releases the encapsulated catalyst when the shell is exposed to a pressure ranging from about 207 kPa (30 psi) to about 689 kPa (100 psi)
Implementation Method 2
catalyst molecules that will accelerate the epoxy-amine reaction to a desirable cure
Data Source
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AI summary
Methods and compositions, and components comprising the compositions, are disclosed relating to improved resin-based adhesives comprising encapsulating at least a catalyst compound. Further methods and compositions are disclosed relating to encapsulated catalysts in uncured resin-based adhesives, said encapsulated catalysts configured to release the catalyst compound and cure the uncured resin-based adhesive on-demand