Epoxy Coating Curing Time vs Chemical Resistance
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Solution Overview
Problem
Current polysulfide-based sealants used in the aerospace industry face challenges such as high shrinkage, humidity and temperature-dependent curing, complex handling, high density, strong odor, and lack of resistance to hydraulic fluids, requiring multiple application steps and long curing times, which are inefficient and material-intensive.
Innovation Solution
A curable coating composition comprising a first part with aliphatic and cycloaliphatic amines as epoxy curing agents and a second part with bisphenol A and F diglycidylether resins, polyfunctional epoxy resins, and optionally novolac epoxy resins, along with inorganic phosphate compounds, allowing for a one-step application that cures quickly at ambient conditions, providing resistance to aggressive media like saltwater and Skydrol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polysulfide-based sealants are used for sealing mass points, then good sealant properties and resistance to deicing fluid are achieved, but the curing time is long (at least 8 h) and multiple application steps are required
Solution Approach 1:
The patent combines the sealing function and protective coating function into a single material composition. The curable coating composition includes polysulfide polymer base resin (providing sealant properties) combined with epoxy compounds and curing agents (providing protective coating properties). This merging eliminates the need for separate sealant application and top coat application, reducing the number of steps and overall curing time while maintaining both sealing and protective functions.
2Reliability
If both sealant and epoxy top coat are applied separately, then fuel resistance and hydraulic fluid resistance are achieved, but the process complexity and material consumption increase
Solution Approach 1:
The patent creates a universal material that performs multiple functions simultaneously. The curable coating composition provides sealing capability (like polysulfide sealant), fuel resistance, and hydraulic fluid resistance (like epoxy top coat). The composition includes polysulfide polymer base resin for sealing, epoxy compounds for chemical resistance, and curing agents for rapid curing. This multi-functional material eliminates the need for separate sealant and coating applications.
Solution Approach 2:
The patent merges the sealing function and protective coating function into a single material composition. The curable coating composition includes polysulfide polymer base resin (providing sealant properties) combined with epoxy compounds and curing agents (providing protective coating properties). This merging eliminates the need for separate sealant application and top coat application, reducing the number of steps and overall curing time while maintaining both sealing and protective functions.
3Reliability
If epoxy top coat is applied over polysulfide sealant, then resistance to hydraulic fluids is achieved, but the total curing time extends to about 4 h for the top coat alone
Solution Approach 1:
The patent changes the curing parameter by using a rapid-curing epoxy curing agent system. The composition includes aromatic polyamine or polyamidoamine curing agents that enable fast curing at ambient temperature. This parameter change reduces the curing time from the typical 4 hours for conventional epoxy top coats to a much shorter duration, making the single-step application process more efficient while maintaining hydraulic fluid resistance.
4Reliability
If polysulfide sealant is used, then flexibility and deicing fluid resistance are achieved, but high shrinkage requires several layers to be applied
Solution Approach 1:
The patent combines the sealing function and protective coating function into a single material composition. The curable coating composition includes polysulfide polymer base resin (providing sealant properties) combined with epoxy compounds and curing agents (providing protective coating properties). This merging eliminates the need for separate sealant application and top coat application, reducing the number of steps and overall curing time while maintaining both sealing and protective functions.
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 solution results in a coating that is tack-free and dust-free within a short period, offering high resistance to chemical influences and reducing material and time consumption, while maintaining mechanical strength and chemical resistance, thus addressing the inefficiencies of polysulfide-based sealants.
Implementation Method 1
The curable coating composition comprises a first part (A) and a second part (B). The first part (A) comprises at least one first epoxy curing agent... The second part (B) comprises at least one epoxy compound...
Implementation Method 2
curing quickly at ambient conditions
Data Source
AI summary
A curable coating composition precursor comprising a first part (A) and a second part (B). The first part (A) comprises at least one first epoxy curing agent selected from aliphatic and cycloaliphatic amines and any combinations and mixtures thereof. The second part (B) comprises at least epoxy compound selected from bisphenol A and bisphenol F diglycidylether resins, and any combinations and mixtures thereof; at least one polyfunctional epoxy resin; at least one novolac epoxy resin; and optionally, at least one reactive diluent, Part (A) and/or part (B) comprise at least one inorganic phosphate compound.