Method of neutralizing the corrosive surface of amine-cured epoxy resins
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorSheng Y. Lee
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Abstract
The corrosive alkaline surface layer of an epoxy resin product formed by the curing of the epoxy with an aliphatic amine is eliminated by first applying a non-solvent to remove most or all of the free unreacted amine and then applying a layer of a chemical reagent to neutralize the unused amine or amine functional groups by forming a substituted urea. The surface then may be rinsed with acetone and then with alcohol. The non-solvent may be an alcohol. The neutralizing chemical reagent is a mono-isocyanate or a mono-isothiocyanate. Preferred is an aromatic mono-isocyanate such as phenyl isocyanate, nitrophenyl isocyanate and naplthyl isocyanate.
Claims8
A process for making a cured epoxy resin polymer, with a corrosion free surface area including:
- forming said polymer with a mixture of an epoxy resin prepolymer and an aliphatic amine, said aliphatic amine acting as a curing agent;
- applying a liquid layer of a mono-isocyanate or mono-isothiocyanate reagent to said surface area of said polymer;
- and
- rinsing said reagent from said surface area.
Dependencies are inferred from the claim text.