Cold cleaning process
AssigneeElf Atochem North America, Inc.
InventorMichael S. Bolmer
Life of this patent
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Abstract
Evaporative cold cleaning of objects wherein the object is contacted in an open environment with a nonazeotropic solvent blend containing an HCFC, HFC or PFC component having no flash point (such as 141b), a higher boiling nonflammable chlorinated solvent (such as perchloroethylene), and a moderately flammable, intermediate boiling, oxygenated organic solvent (such as n-butanol).
Claims7
A method for cold cleaning of an object which comprises the steps of (a) contacting said object in an open environment with a nonazeotropic solvent blend consisting essentially of about 1-60 weight % of a hydrochlorofluorocarbon, hydrofluorocarbon, or perfluorocarbon halocarbon component having 2-4 carbons, a boiling point of about 25.degree.-45.degree. C., and no flash point;
- about 1-30 weight % of a nonflammable chlorinated solvent component with a boiling point of about 80.degree.-130.degree. C. selected from perchloroethylene, trichloroethylene, or mixtures thereof;
- and about 1-40 weight % of an oxygenated organic solvent component which has a flash point over 0.degree. C., has a boiling point intermediate that of the other two components, and is selected from methanol, ethanol, isopropanol, isopropyl acetate, dimethyl carbonate, n-propanol, 2-butanol, ethyl proprionate, n-propyl acetate, methylpropylketone, diethylketone, n-butyl formate, isobutanol, n-butanol, and mixtures thereof, said components and their proportions being chosen such that the blend has a substantially lower ozone depletion potential than 1,1,2-trichloro-1,2,2-trifluoroethane or 1,1,1-trichloroethane and, when evaporated, has resultant vapor fractions and liquid fractions each having no flash point;
- and (b) air drying the object.
A method for cold cleaning of an object which comprises the steps of (a) contacting said object in an open environment with a nonazeotropic solvent blend consisting essentially of 1-60 weight % of a halocarbon component, 1,1-dichloro-1-fluoroethane, having a boiling point of about 31.degree. C. and no flash point;
- about 1-30 weight % of a nonflammable chlorinated solvent component with a boiling point of about 80.degree.-130.degree. C. selected from perchloroethylene, trichloroethylene, or mixtures thereof;
- and about 1-40 weight % of an oxygenated organic solvent component which has a flash point over 0.degree. C., has a boiling point intermediate that of the other two components, and is selected from methanol, ethanol, isopropanol, isopropyl acetate, dimethyl carbonate, n-propanol, 2-butanol, ethyl propionate, n-propyl acetate, methylpropylketone, diethylketone, n-butyl formate, isobutanol, n-butanol, and mixtures thereof, said components and their proportions being chosen such that the blend has a substantially lower ozone depletion potential than 1,1,2-trichloro-1,2,2-trifluoroethane or 1,1,1-trichloroethane and, when evaporated, has resultant vapor fractions and liquid fractions each having no flash point;
- and (b) air drying the object.
Dependencies are inferred from the claim text.