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US 5,334,323 AGranted
Deicing or antiicing fluids for aircraft
AssigneeBASF SE
InventorsHans Schrimpf, Hans Krebs, Gert Liebold, Guenter Frey
Life of this patent
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Abstract
Deicing/antiicing fluids for aircraft which contain essentially glycols, crosslinked polyacrylic acid, a nonionic surfactant based on alkoxylated C.sub.10 -C.sub.20 alcohols, corrosion inhibitors, a mixture of NaOH and KOH, an antioxidant and water, reduce the loss of lift by having improved runoff characteristics from the wings while giving a refreeze holdover time of not less than 30 minutes.
Claims11
A deicing/antiicing fluid for aircraft based on a glycol, water and a crosslinked polyacrylic acid as thickener, consisting essentially of:
- a) 40-70% by weight of a glycol selected from the group consisting of the alkylene glycols of 2 or 3 carbon atoms and oxyalkylene glycols o from 4 to 6 carbon atoms, or a mixture thereof,
- b) 0.1-1.0% by weight of a crosslinked polyacrylic acid which in the form of a 0.5% strength by weight aqueous solution at pH 7.0 a Brookfield viscometer at 20 rpm,
- c) 0.02-1.5% by weight of a nonionic surfactant formed from an alcohol of from 10 to 20 carbon atoms reacted with from 1 to 10 molecules of a low molecular weight alkoxide,
- d) 0.05-2.0% by weight of one or more corrosion inhibitors,
- e) 0.2-0.7% by weight of a mixture of potassium hydroxide and sodium hydroxide containing up to 70% by weight of potassium hydroxide, or of pure sodium hydroxide, to the fluid pH to 7.0-9.5,
- f) 0.01-0.1% by weight of an antioxidant, and
- g) water to 100% by weight, all the weight percentages being based on the weight of the fluid, and wherein the deicing/antiicing fluid has a holdover time of at least about 30 minutes as measured by the AEA freezing rain endurance test and a viscosity of from about 2000 mPa.s to not greater than about 4000 mPa.s when measured at 20.degree. C. using a Brookfield viscometer at 0.3 rpm.
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Dependencies are inferred from the claim text.