Aqueous fire-fighting foams with reduced fluorine content
Aqueous film forming firefighting composition concentrates are provided that contain an effective amount of a monomeric zwitterionic or anionic C 6 perfluoroalkyl surfactant having a molecule weight less than 800 daltons. The compositions also contain an effective amount of a foam stabilizing agent, and an effective amount of at least one non-fluorinated surfactant. The composition has less than 0.8% F, and is substantially free of any surfactant containing a perfluoroalkyl group containing more than 6 carbon atoms. The composition meets Military Specification MIL-F-24385F.
1. An aqueous film-firefighting composition concentrate comprising:
(a) 0.5 to 20 wt. % of a perfluoroalkyl surfactant having a structure represented by the formula I:
R f —X-Y-L-Z I:
wherein R f is C 6 straight or branched chain perfluoroalkyl;
X is C 2 -C 12 straight or branched chain alkylene, or C 2 -C 12 straight or branched chain alkenylene containing 1 or 2 alkene moieties;
Y is selected from the group consisting of:
—S-CH 2 CH(R 1 )CON(R 2 )—, —O—CH 2 CH 2 —N(R 3 )(R 4 )—;
—O—CH 2 CH(OR 5 )CH 2 —N(R 3 )(R 4 )—; —O—CH 2 CH(OR 5 )CH 2 —S—;
—S—CH 2 CH(OR 5 )CH 2 —N(R 3 )(R 4 )—; and —S—CH 2 CH(OR 5 )CH 2 —S—;
L is C 2 -C 12 straight or branched chain alkylene, where one carbon atom in the chain optionally is replaced by N(R 6 )(R 7 )—; and
Z is —OSO 3 − , —SO 3 − , or —CO 2 − ,
wherein R 1 , R 2 , R 3 , R 4 , R 6 and R 7 , independently are H or straight or branched chain C 1 -C 6 alkyl, and R 5 is H or straight or branched chain C 1 -C 6 alkyl or trialkylsilyl;
(b) a foam stabilizing agent, and
(c) at least one non-fluorinated surfactant,
wherein said composition is substantially free of a perfluorinated surfactant that does not conform to formula I and wherein the final concentration of fluorine atoms on a weight percentage basis is less than 0.8%.
2. The composition according to claim 1 wherein said non-fluorinated surfactant is an anionic surfactant.
3. The composition according to claim 1 , wherein said foam stabilizing agent is a glycol ether.
4. The composition according to claim 1 , further comprising a corrosion inhibitor.
5. The composition according to claim 1 , wherein Y is —S—CH 2 C(R 1 )CON(R 2 )—.
6. The composition according to claim 5 , wherein R 1 is H or straight chain alkyl and R 2 is H.
7. The composition according to claim 1 , wherein Y is —O—CH 2 CH 2 —N(R 3 )(R 4 )—.
8. The composition according to claim 7 , wherein R 3 and R 4 are H or methyl.
9. The composition according to claim 1 , wherein Y is —O—CH 2 CH(OR 5 )CH 2 —N(R 3 )(R 4 )—.
10. The composition according to claim 9 , wherein R 3 and R 4 are H or methyl, and R 5 is H or trialkylsilyl.
11. The composition according to claim 1 , wherein Y is —O—CH 2 CH(OR 5 )CH 2 —S—.
12. The composition according to claim 1 , wherein R 5 is H or trialkylsilyl.
13. The composition according to claim 1 , wherein Y is —S—CH 2 CH(OR 5 )CH 2 —N(R 3 )(R 4 )—.
14. The composition according to claim 13 , wherein R 3 and R 4 are H or methyl, and R 5 is H or trialkylsilyl.
15. The composition according to claim 1 , wherein Y is —S—CH 2 CH(OR 5 )CH 2 —S—.
16. The composition according to claim 15 , wherein R 5 is H or trialkylsilyl.
17. The composition according to claim 1 , further comprising an alkylpolyglycoside in the amount of 0.3 to 7%.
18. The composition according to claim 1 , further comprising a polysaccharide gum in an amount of 0.1 to 5%.
19. The composition according to claim 1 , comprising a plurality of perfluoroalkyl surfactants of the formula I.
20. The composition according to claim 1 , wherein said foam stabilizing agent is present in an amount of 1-50% and said non-fluorinated surfactant is present in an amount of 0.1 to 30%.
21. A firefighting foam, comprising a composition according to claim 1 , and an aqueous liquid.
22. The foam according to claim 21 , wherein said aqueous liquid is brackish water or seawater.
23. A method of making a fire-fighting foam, comprising foaming a composition according to claim 1 with an aqueous liquid.
24. The method according to claim 23 , wherein said aqueous liquid is brackish water or seawater.
25. An aqueous film-firefighting composition concentrate comprising:
(a) 0.5-20 wt. % of a perfluoroalkyl surfactant having a structure represented by the formula I:
R f —X-Y-L-Z I:
wherein R 1 is C 6 straight or branched chain perfluoroalkyl;
X is C 2 -C 12 straight or branched chain alkylene, or C 2 -C 12 straight or branched chain alkenylene containing 1 or 2 alkene moieties;
Y is selected from the group consisting of:
—S—CH 2 CH(R 1 )CON(R 2 )—, —O—CH 2 CH 2 —N(R 3 )(R 4 )—;
—O—CH 2 CH(OR 5 )CH 2 —N(R 3 )(R 4 )—; —O—CH 2 —CH(OR 5 )CH 2 —S—;
—S—CH 2 CH(OR 5 )CH 2 —N(R 3 )(R 4 )—; and —S—CH 2 CH(OR 5 )CH 2 —S—;
L is C 2 -C 12 straight or branched chain alkylene, where one carbon atom in the chain optionally is replaced by —N(R 6 )(R 7 )—; and
Z is —OSO 3 − , —SO 3 − , or —CO 2 − ,
wherein R 1 , R 2 , R 3 , R 4 , R 6 and R 7 , independently are H or straight or branched chain C 1 -C 6 alkyl, and R 5 is H or straight or branched chain C 1 -C 6 alkyl or trialkylsilyl;
(b) a fluorinated foam stabilizing agent containing 3 to 7 perfluorinated carbon atoms, and
(c) at least one non-fluorinated surfactant, and
wherein said composition is substantially free of a perfluorinated surfactant that does not conform to formula 1.
26. A fire-fighting foam, comprising a composition according to claim 25 and an aqueous liquid.
27. The foam according to claim 25 , wherein said aqueous liquid is brackish water or seawater.
28. A method of making a fire-fighting foam, comprising foaming a composition according to claim 25 with an aqueous liquid.
29. The composition according to claim 1 , wherein Y is selected from the group consisting of:
—S—CH 2 CH(R 1 )CON(R 2 )—, —O—CH 2 CH(OR 5 )CH 2 —S—; and —S—CH 2 CH(OR 5 )CH 2 —S—.
30. The composition according to claim 29 , wherein X is a C 2 -C 3 straight chain alkylene or alkenylene; L is C 2 -C 12 straight or branched chain alkylene; R 1 is methyl; and R 2 and R 5 are H.
31. An aqueous film-firefighting composition concentrate comprising:
(a) 0.5 to 20 wt. % of a zwitterionic and/or anionic perfluoroalkyl surfactant having a structure represented by the formula I:
R f —X—Y-L-Z I:
wherein R f is a C 6 straight or branched chain perfluoroalkyl;
X is a C 2 -C 12 straight or branched chain alkylene, or C 2 -C 12 straight or branched chain alkenylene containing 1 or 2 alkene moieties;
Y is selected from the group consisting of: —S—CH 2 CH(R 1 )CON(R 2 )—,
—O—CH 2 CH 2 —N(R 3 )(R 4 )—; —O—CH 2 CH(OR 5 )CH 2 —N(R 3 )(R 4 )—;
—O—CH 2 CH(OR 5 )CH 2 —S—; —S—CH 2 CH(OR 5 )CH 2 —N(R 3 )(R 4 )—; and
—S—CH 2 CH(OW)CH 2 —S—;
L is C 2 -C 12 straight or branched chain alkylene, where one carbon atom in the chain optionally is replaced by —N(R 6 )(R 7 )—, and
Z is —OSO 3 − , —SO 3 − , or —CO 2 − ,
wherein R 1 , R 2 , R 3 , R 4 , R 6 and R 7 , independently are H or straight or branched chain C 1 -C 6 alkyl, and R 5 is H or straight or branched chain C 1 -C 6 alkyl or trialkylsilyl;
(b) a foam stabilizing agent, which comprises a glycol ether and/or a fluorinated foam stabilizing agent containing 3 to 7 perfluorinated carbon atoms; and
(c) at least one non-fluorinated surfactant,
wherein said composition does not contain a perfluorinated surfactant that does not conform to formula I.
32. The concentrate of claim 31 , wherein Y is selected from the group consisting of:
—S—CH 2 CH(R 1 )CON(R 2 )—; —O—CH 2 CH(OR 5 )CH 2 —S—; and
—S—CH 2 CH(OR 5 )CH 2 —S—;
X is a C 2 -C 3 straight chain alkylene or alkenylene;
R 2 are H or methyl; and R 5 is H.
33. A fire-fighting foam, comprising the concentrate of claim 31 and an aqueous liquid.