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US 5,788,781 AGranted
Method for cleaning an oil-coated substrate
AssigneeUnion Oil Company of California
InventorDonald C. Van Slyke
Life of this patent
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Abstract
A method for cleaning oil-contaminated substrates employing a composition includes a diluent oil, a first surfactant having a HLB value of at least 10, and a second surfactant having a higher HLB value. The difference in the HLB values of the first and second surfactants is at least 3 and a mixture of the surfactants would have a HLB value of at least 11.
Claims27
A method for cleaning an oil-coated substrate, the method comprising the sequential steps of:
- (A) contacting at least a portion of the oil-coated part of the substrate with a composition comprising:
- (a) a first surfactant having a HLB value of at least 10;
- (b) a second surfactant having a higher HLB value, where the difference in the HLB values of the first and second surfactants is at least 3 and a mixture of the surfactants has a HLB value of at least 11;
- and
- (c) at least one nonpolar diluent oil;
- and
- (B) rinsing at least a portion of the oil-coated substrate contacted in step (A) with water, where a material consisting of the first surfactant, the second surfactant, and the nonpolar diluent oil is a solution, the respective volumes of the first surfactant, the second surfactant, and the nonpolar diluent oil in the material being the same as employed in the composition.
4 more elements
Dependencies are inferred from the claim text.