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Publication numberUS2716068 A
Publication typeGrant
Publication dateAug 23, 1955
Filing dateOct 21, 1952
Priority dateOct 21, 1952
Publication numberUS 2716068 A, US 2716068A, US-A-2716068, US2716068 A, US2716068A
InventorsFain Jacob M, Hewitt Norman L
Original AssigneeFain Jacob M, Hewitt Norman L
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
De-icing and freeze depressant composition
US 2716068 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Patented Aug. 23, 19355 DE-ICING AND FREEZE DEPRESSANT COMPOSITION Jacob M. Fain, Brooklyn, N. Y., and Norman L. Hewitt, Red Bank, N. 1., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy No Drawing. Application October 21, 1952, Serial No. 316,096

3 Claims. (Cl. 106-13) This invention relates to combined de-icing and freezedepressant substances with special application to aircraft.

The formation of ice on aircraft parts has offered an important problem in aircraft use, and this problem has been accentuated by long range and high altitude flights,

often under conditions of excessive humidity. Heretofore, for de-icing purposes use has been made of various freeze-depressants capable of remaining in solution at lower temperatures; however, defects have been found in many of these substances when subjected to the severe requirements of extremely low temperature flight conditions.

An object of the present invention is to provide a surfacing material for aircraft surfaces which is effective as a de-icer to temperatures as low as 65 F. A further object is to provide a surface coating which can maintain itself free of ice for as long as ten hours under sub-freezing temperatures and without reapplication. An important object also is to provide an ice protective coating which is free of ingredients harmful to the coated substances. Still another object is to provide a coating all of the ingredients of which are effective to prevent or remove ice formations.

Further objects include the provision of a coating which is non-inflammable, which is not highly toxic, and which does not crystallize or separate in the range of use. Other objects will appear on consideration of the following de scription of a preferred form of the invention.

Monohydric alcohols, such as methyl alcohol, have long been in use as freeze depressants. These alcohols however are disadvantageous in their corrosive characteristics and high volatility requiring frequent replacement, and are therefore inferior to the polyhydric alcohols including the glycols which are stable at relatively higher temperatures, although possessing metal corrosive tendencies. Further, the use of certain soluble salts such as the salts of nitrous acid have been found useful as freeze depressants due to their high effectiveness in reduction of the freezing point as well as the limited quantities necessary to produce results.

Although any one of the above mentioned groups may be employed alone as a freeze depressant and de-icer, I have found that a composition including ethylene glycol (HOCH2CH2OH) from the glycol group and potassium thiocyanate (KCNS) and preferably including sodium nitrite (NaNOz) from the soluble salts gives highly superior results. All of these substances are freeze depressant in action and hence no inactive carrier substance is needed. The ethylene glycol with its low volatility serves as the basic material of the composition. Potassium thiocyanate dissolves readily in the glycol and thus augments the de-icing property of the composition; the sodium nitrite in addition to its freeze depressant characteristic and easy solubility imparts corrosion resistance to the composition.

In addition to the mentioned properties of this composition, it possesses other important virtues such as non-inflammability, lack of excessive toxicity, a marked retention of the deicing property, after application, for from one-half to ten hours depending on the precipitation and an absence of adverse effects on the base metals including aluminum, aluminum alloys, magnesium alloys, steel, aircraft enamels, lacquers and transparent plastics.- Moreover, the solution has a pour point below -65 F., does not crystallize or separate between 65 F. and 170 F. and maintains its useful action either in bulk mass or film formation. Outstandingly, however, the composition effectively removes ice and frost from exterior surfaces of aircraft wings, fuselage, control units and the like down to temperatures as low as 65 F.

While the proportions of the substances used in the composition are not critical, the ethylene glycol constituting approximately two-thirds by weight of the solution of potassium thiocyanate in ethylene glycol, these substances should be included within the following limits to avoid crystallization.

Parts by weight Ethylene glycol 60-66 Potassium thiocyanate 3034 Sodium nitrite 10-0 However, best results in full agreement with the objects of this invention are obtained using the following values.

Ethylene glycol 60 Potassium thiocyanate 30 Sodium nitrite 10 A composition as thus limited is found to have the following characteristics:

Specific gravity 1.35.

Pour point -94.0" F.

Flash point 302.0 F.

Corrosion Non-corrosive to aluminum, aluminum alloys, magnesium alloys and steel.

Where de-icing is the prime consideration, the proportions of glycol may be increased. In making the compositions as described above the ingredients are mixed together until solution has been effected.

It is pointed out that, by elimination of an inert carrier, both of the mutually soluble substances ethylene glycol and potassium thiocyanate are effective as freeze depressants, thus obtaining full advantage of the coating materials. It is further observed that the usefulness of the coating results from the combined action of the salt and glycol, neither of these substances separately producing the marked depression of freezing point and permanence of effect, combined with non-toxicity, non-inflammability and freedom from crystallization or separation inside the range of use including temperatures as low as 65 F. The addition of the sodium nitrite augments the depressant action and in addition, imparts important resistance to corrosive tendencies.

It is of course, evident that under certain conditions and to meet requirements of cost, etc., substances other than these specifically mentioned but having similar properties, may be used, although producing results possibly inferior to the preferred composition. For example, usable glycols include diethylene glycol, triethylene glycol, propylene glycol and polyethylene glycol. Other usable soluble salts include ammonium nitrate, potassium acetate, ammonium dichromate, ferric chloride, sodium nitrate, sodium thiocyanate and urea. In utilizing these varied substances the glycol and the sodium nitrite should form two of the elements and the proportionate parts should follow those of the preferred composition. Accordingly, the scope of the invention is restricted only as required by the claims as hereto appended.

, 4 V col, the glycol constituting approximately two-thirds 1: weight of thecomposition.

References Cited in the file of this patent UNITED STATES PATENTS Sperr Nov. 6, 1923 Bayes Apr. l1, 1939 FOREIGN PATENTS 7 10 119,642 Anstralia Mar. 15, 1945

Patent Citations
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US1473327 *Dec 7, 1921Nov 6, 1923Koppers Co IncAntifreeze composition
US2153952 *Aug 6, 1937Apr 11, 1939Carbide & Carbon Chem CorpAntifreeze corrosion inhibitor
AU119642B * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2918052 *Mar 14, 1957Dec 22, 1959Armour Res FoundHeat-releasing anti-icing means
US3227654 *Nov 7, 1962Jan 4, 1966Standard Oil CoDeicer composition
US3541805 *Feb 26, 1969Nov 24, 1970Us AgricultureMethod and apparatus for vapor condensation
US3940249 *Jun 17, 1974Feb 24, 1976Streck Laboratories, Inc.Laboratory testing procedure
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US4162347 *Dec 14, 1977Jul 24, 1979The Dow Chemical CompanyMethod for facilitating transportation of particulate on a conveyor belt in a cold environment
US4163079 *Dec 14, 1977Jul 31, 1979The Dow Chemical CompanyMethod for facilitating transportation of particulate on a conveyor belt in a cold environment
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US7438827Dec 21, 2006Oct 21, 2008Cargill, IncorporatedMethod and apparatus for on-site mixing of liquid deicer
US7461969Dec 21, 2006Dec 9, 2008Cargill, IncorporatedMethod and apparatus for on-site mixing of liquid deicer
US7461971Dec 21, 2006Dec 9, 2008Cargill, IncorporatedMethod and apparatus for on-site mixing of liquid deicer
US8048332Nov 10, 2009Nov 1, 2011Georgia-Pacific Chemicals LlcMethod for inhibiting ice formation and accumulation
US8226848Sep 22, 2011Jul 24, 2012Georgia-Pacific Chemicals LlcMethod for inhibiting ice formation and accumulation
US20040129829 *Nov 22, 2002Jul 8, 2004Michael HoerleMethod and apparatus for on-site mixing of liquid deicer
U.S. Classification106/13, 62/82, 252/70
International ClassificationC09K5/20, C09K5/00
Cooperative ClassificationC09K5/20
European ClassificationC09K5/20