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AssigneePennwalt Corporation
InventorsEdward John Belcak, Leo Francis Corcoran
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This invention relates to liquid compositions and methods of using them for removing coatings from coated metal surfaces, particularly metals, and especially those metals subject to attack by corrosive liquids. The compositions comprise from one-fourth to about 10% by weight of alkali metal hydroxide, from 40 to about 60% by weight of at least one liquid high boiling oxygenated solvent, and from 40 to about 60% by weight of at least one liquid high boiling amine. Optionally, the compositions may contain from one-half to about 20% by weight of a surface active or wetting agent. The method of use comprises applying the anhydrous liquid composition to the coated object at a temperature from ambient up to the boiling point of the composition for a time sufficient to loosen or remove the coating.
The metal coating removal composition comprising an anhydrous liquid mixture of one-fourth to about 10% by weight of alkali metal hydroxide, from 40 to about 60% by weight of at least one oxygenated organic solvent liquid at ambient temperatures and having a boiling point in excess of about 100.degree.C . selected from the group consisting of alcohols, carbonyls, esters, amides, lactones, tetramethyl urea, diphenyl ether and dimethyl sulfoxide and from 40 to about 60% by weight of at least one amine liquid at ambient temperatures and having a boiling point above about 65.degree.C.
The process for removing coatings from metal by applying to the coated metal an anhydrous liquid mixture comprising one-fourth to about 10% by weight of alkali metal hydroxide, from 40 to 60% by weight of at least one oxygenated organic solvent liquid at ambient temperatures and having a boiling point in excess of about 100.degree.C. selected from the group consisting of alcohols, carbonyls, esters, amides, lactones, tetramethyl urea, diphenyl ether and dimethyl sulfoxide and from 40 to about 60% by weight of at least one amine liquid at ambient temperatures and having a boiling point above about 65.degree.C., for a time sufficient to loosen the said coatings and thereafter rinsing the metal to remove the loosened coatings.
Dependencies are inferred from the claim text.