Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
1998-01-30
2001-01-30
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
C252S003000, C560S150000, C560S169000, C560S171000, C562S565000, C562S571000, C562S574000
Reexamination Certificate
active
06180826
ABSTRACT:
This invention concerns new polyperfluoroalkyl surfactants, water-soluble derivatives of functional polycarboxylic polymers containing no organic quaternary nitrogen atoms, with properties that are not only oleophobic, but strongly alcophobic, usable alone or with emulsifiers having a synthetic or protein foaming base to fight fires caused by polar liquids or hydrocarbons.
For several decades perfluoroalkyl surfactants,have been used in the manufacture of fire-extinguishing foams. These fluorinated products make the foam oleophobic, thereby protecting it against hydrocarbon contamination and reinforcing its efficacy in extinguishing fires caused by hydrocarbons.
All these foams, however, are ineffective against fires caused by polar liquids; they are destroyed on contact with dehydrating liquids, such as alcohol, ketones, etc. These surfactants are not alcophobic.
For fighting fires caused by polar liquids, it has been suggested (DP-6976461940) that complex salts, such as ammoniac zinc caprylate for instance, be incorporated into the hydrolysed protein solution. These foams are somewhat resistant to alcohol fires, but much less so against hydrocarbon fires because of the presence of fatty soaps. This defect can be offset by adding oleophobic fluorinated surfactants available on the market. There still remains, however, a major problem: when these emulsifiers are diluted in water for use, they are hydrolysed within minutes and lose their foaming and extinguishing properties.
To preserve the emulsifier's qualities during premixing, it has been suggested that the complex ammoniac salt be replaced in the concentrate with polysaccharide-type polymers; and that an oleophobic fluorinated surfactant (U.S. Pat. No. 4,060,489; FR 8003640) be incorporated to reinforce the foam's resistance to hydrocarbon fires. These liquid emulsifiers are widespread on the market. They are prepared with a synthetic or protein foaming base and are called pseudoplastic emulsifiers for their rheological behaviour. In general, they are remarkably effective for extinguishing polar liquid and hydrocarbon fires; but their viscosity makes these concentrates hard to use especially at low temperatures.
The authors' Patent FR 88-13612 suggests improving the fluidity of pseudoplastic emulsifiers by reducing the concentrate's polysaccharide content and by adding a reactive quaternary perfluoroalkyl polyamine (patent FR 88-11345, by the authors) in order to convert the polysaccharide into a fluorinated substance resistant to polar liquid and hydrocarbon fires.
Other polymers have also been suggested for resistance to alcohol fires: methylic vinyl ether or maleic anhydride copolymer salts, for instance. The problem with the latter is in the fact that a very large amount of the foaming solution is needed, which makes it hard to use and still produces a poor result.
U.S. Pat. 2378629 and Australian patent no. 40709-72 suggest using an alkylamide derivative of the above-mentioned copolymer to replace the protein hydrolysed in the extinguishing foam. These foams are ineffective against polar liquid fires and mediocre against hydrocarbon fires.
Several patents suggest using monoperfluoroalkyl polyacrylamides in the omega position to stabilise protein foams against hydrocarbon fires, but such foams are ineffective against polar liquid fires.
On the market, there are three types of these perfluoroalkyl polyacrylamide compounds:
Patent JP 04 126 709 describes ether alkenyl and periluoroalkyl maleic anhydride copolymers in which the fluorinated group is placed in the carbon chain but not bonded to the carboxyl group. This product is intended for waterproofing, so it is not for use in the preparation of aqueous foams.
Patent JP 03 243 609 causes polyacrylic acid to react with dihydroperfluorooctylamine to yield a hydrofuge product. The amide nitrogen atom obtained does not have the hydrophilic group necessary to promote alcophobia and water-solubility.
Fluorinated surfactants that are both alcophobic and oleophobic are described in patents FR 88/12152, FR 88/11345 and FR 88/113612 by the authors. Their quality is significant, but the fact these molecules necessarily contain a quaternary nitrogen atom limits their compatibility With anionic surfactant agents and protein derivatives.
To offset all the problems mentioned above, we sought according to the invention to synthesise new fluorinated surfactants that were both alcophobic and oleophobic and compatible with anionic surfactant agents and protein derivatives. Thus the novelty of the products according to the invention, in comparison with known surfactants, lies in the fact they are alco-oleophobic, compatible with anionic surfactant. agents and protein derivatives, that these macromolecules contain several perfluoroalkyl groups and have no organic quaternary nitrogen atom; the radicals carrying a perfluoroalkyl group are bonded to the carboxylic functions belonging to the polymer through an ester or amide bond; the nitrogen atom carries a hydrophilic group to promote alcophobia. The following examples illustrate the invention and are in no case limitative:
REFERENCES:
patent: 4015612 (1977-04-01), Pavlik
patent: 4089804 (1978-05-01), Falk
patent: 4160777 (1979-07-01), Loudas
patent: 4303524 (1981-12-01), Hisamoto
patent: 5725789 (1998-03-01), Huber
patent: 0 390 905 (1990-10-01), None
patent: 2 637 506 (1988-10-01), None
patent: 90 03966 (1990-04-01), None
Szonyi Francois
Szonyi Istvan
Szonyi Stephane
Laboratoire 3 S
Pillsbury Madison & Sutro LLP
Shippen Michael L.
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