Clear Aircraft Sealant Composition for Fuel and Hydraulic Fluid Exposure
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Solution Overview
Problem
Current aircraft sealants are prone to degradation and loss of properties when exposed to common aircraft fluids like hydraulic fluids and Jet A fuel, have long cure times, are often opaque, difficult to remove, and lack sufficient elasticity for joint movement, making them inadequate for the harsh aircraft environment.
Innovation Solution
Development of a two-part polyurethane or polyurea sealant that is resistant to Jet A fuel and various hydraulic fluids, cures quickly, is optically clear, elastomeric, and removable, with a cartridge assembly for pneumatic mixing and spraying, and a tape or injectable form for versatile application, ensuring toughness, workability, and removability while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aircraft sealants are used, then they provide basic sealing function, but they degrade and lose properties when exposed to aircraft fluids like hydraulic fluids and Jet A fuel
Solution Approach 1:
The patent modifies the chemical composition parameters of the sealant by incorporating specific polymers (polyurethane, polyurea, silicone rubber) and additives that change the material's chemical resistance properties, enabling it to withstand degradation from aircraft fluids while maintaining sealing functionality
Solution Approach 2:
The sealant is formulated as a composite material system combining multiple polymers, crosslinking agents, and functional additives to achieve both fluid resistance and elastic properties, creating a material that resists degradation from hydraulic fluids and fuel while maintaining joint flexibility
2Productivity
If conventional sealants are used, then they provide sealing coverage, but they have long cure times (e.g., 7 days at 77°F)
Solution Approach 1:
The patent adjusts the chemical reaction parameters by incorporating fast-curing agents and optimizing the polymerization kinetics, reducing the cure time from 7 days to a significantly shorter duration while maintaining complete curing and seal integrity
Solution Approach 2:
The accelerated cure formulation allows the sealant to rapidly progress through the curing stages, achieving functional cure much faster than conventional sealants, thereby reducing aircraft downtime and enabling quicker return to service
3Difficulty of detecting and measuring
If conventional sealants are used, then they provide coverage, but they are opaque and prevent visual inspection of deterioration beneath
Solution Approach 1:
The patent formulates the sealant with transparent or translucent optical properties, eliminating the opacity of conventional sealants, which allows visual inspection of the underlying surface and detection of deterioration through the cured sealant layer
4Strength
If rigid sealants are used, then they provide structural strength, but they lack elasticity for joint movement in aircraft
Solution Approach 1:
The patent optimizes the polymer selection and crosslinking density parameters to achieve a balanced material property profile, creating a sealant that maintains sufficient structural strength for sealing while incorporating elastic polymers that allow joint movement and flexibility
Solution Approach 2:
The sealant combines rigid and elastic polymer components in a composite formulation, creating a material that exhibits both strength for structural sealing and elasticity for accommodating aircraft joint movements, preventing crack formation and maintaining seal integrity
5Strength
If permanent bond sealants are used, then they provide strong adhesion, but they are difficult to remove for replacement
Solution Approach 1:
The patent adjusts the adhesion parameters by selecting polymers and surface treatment combinations that provide strong initial bonding for sealing purposes while maintaining controlled adhesion strength that allows for removal and replacement when necessary, balancing permanent sealing with repairability
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 sealant achieves rapid cure, high elasticity, and resistance to aircraft fluids, allowing for effective sealing and corrosion protection while being removable and visually clear, thus addressing the limitations of existing sealants by providing a durable, flexible, and easily inspectable coating.
Implementation Method 1
These embodiments are also typically cure in place from a two part polyurethane or polyurea mix, with cure to a visibly clear coating
Data Source
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Figure 1A~1B
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AI summary
A number of sealants are provided that are resistant to degradation by aircraft fluids. In some embodiments, the sealants are resistant to degradation by Jet A fluid and at least one of the three types of hydraulic fluids typically used in aircraft. These embodiments are also typically cure in place from a two part polyurethane or polyurea mix, with cure to a visibly clear coating. In some embodiments, they may be sprayed on an aircraft surface or applied by hand (brush or injectable). In other of these embodiments, the sealants comprise, at least in part, a cured, soft, tacky polyurethane gel that is resistant to at least one of a synthetic hydrocarbon based or mineral oil based hydraulic fluid.