# US 5,334,323 A · Deicing or antiicing fluids for aircraft

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- Number: US 5,334,323 A
- Document ID: US5334323A
- Status: Granted
- Kind: A
- Application number: 07/687,209
- Filed: 1991-04-18
- Granted: 1994-08-02
- Earliest claimed: 1988-09-23
- Assignees: BASF SE
- Inventors: Hans Schrimpf; Hans Krebs; Gert Liebold; Guenter Frey
- Web page: https://patentgrep.com/patent/US5334323A

## CPC

- C09K 3/185: {Thawing materials}
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## 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.

## Claims

### Claim 1

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.

### Claim 2 (depends on 1)

A fluid as claimed in claim 1, wherein component (c) is an oxo alcohol of from 10 to 20 carbon atoms in the carbon chain which has been ethoxylated with from 1 to 10 molecules of ethylene oxide.

### Claim 3 (depends on 1)

A fluid as claimed in claim 1, wherein component (e) is a mixture of potassium hydroxide and sodium hydroxide in a ration of from 2.5:1 to 1:2.5.

### Claim 4 (depends on 1)

A fluid as claimed in claim 1, which contains components a) to f), in the following amounts:
a) from 50 to 60% by weight
b) from 0.2 to 0.6% by weight
c) from 0.02 to 1.5% by weight
d) from 0.1 to 2.0% by weight
e) from 0.2 to 0.7% by weight
f) from 0.01 to 0.1% by weight
g) water to make up to 100% by weight.

### Claim 5 (depends on 1)

A fluid as claimed in claim 1, wherein said glycol is selected from the group consisting of 1,2-propylene glycol, 1,3-propylent glycol, diethylene glycol and mixtures thereof.

### Claim 6 (depends on 2)

A fluid as claimed in claim 2, wherein said nonionic surfactant is an oxo alcohol of from 13 to 15 carbon atoms, ethoxylated with 3 molecules of ethylene oxide.

### Claim 7 (depends on 6)

A fluid as claimed in claim 6, wherein said holdover time is 35 times.

### Claim 8 (depends on 7)

A fluid as claimed in claim 7, wherein said holdover time is 37 minutes.

### Claim 9 (depends on 8)

A fluid as claimed in claim 8, wherein said holdover time is 39 minutes.

### Claim 10 (depends on 1)

A fluid as claimed in claim 1, said nonionic surfactant being present in an amount of from 0.02 to 0.3%.

### Claim 11 (depends on 10)

A fluid as claimed in claim 10, said nonionic surfactant being present in an amount of from 0.05 to 0.3%.