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US 4,290,819 AGranted
Method and composition for the removal of phenolic resin coatings from aluminum
AssigneeThe Boeing Company
InventorsEdwin P. Cornwall, Walter Batiuk
Life of this patent
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Abstract
A composition and process for the removal of phenolic resin composites from aluminum and its alloys which results in a minimum of corrosion to said metals. The process uses a solvent solution of nitric acid, a hexavalent chromium and incidental water in the proportions of about 0.01-0.12 moles of hexavalent chromium and 1-1.7 moles of H.sub.2 O per mole HNO.sub.3.
Claims9
A process for removing the phenolic resin coating from a phenolic resin coated aluminum object, comprising the steps of:
- applying an aqueous solvent solution consisting essentially of from 60 to 76% by weight of HNO.sub.3 and from 2 to 11% by weight of CrO.sub.3 to the phenolic resin coating,
- maintaining said solvent solution at a temperature of about 160.degree. to 170.degree. F. for a sufficient time to dissolve said phenolic coating, and
- rinsing with water to remove the solution and drying.
A process for removing a phenolic coating from an aluminum substrate, comprising the steps of:
- applying an aqueous acidic solvent solution consisting essentially of from about 0.01 to 0.12 moles hexavalent chromium, and from about 1 to 1.7 moles water for each mole HNO.sub.3 to the phenolic coating,
- maintaining said solution in contact with said phenolic coating at a temperature in the range of 100.degree. to 180.degree. F. for a time sufficient to remove said coating, and
- rinsing said solution from the aluminum substrate.
Dependencies are inferred from the claim text.