GB2122080A

GB2122080A - Liquid fire-extinguishing concentrates

Info

Publication number: GB2122080A
Application number: GB08315811A
Authority: GB
Inventors: Salvador Morata Lopez
Original assignee: LOSTAO FRANCISCO JAVIER
Current assignee: LOSTAO FRANCISCO JAVIER
Priority date: 1982-06-09
Filing date: 1983-06-09
Publication date: 1984-01-11
Also published as: IT1194262B; EP0096425A1; ES8307512A1; IL68933A0; AU1566083A; BR8303068A; PT76858B; IT8321530A0; PT76858A; ES512990A0; JPS5985674A; GB8315811D0; FR2530477A1; DD209741A5

Description

SPECIFICATION Liquid fire-extinguishing concentrate and a process for its preparation The invention relates to a liquid fire-extinguishing concentrate and a process for its preparation. As well as extinguishing agents in powder form, numerous extinguishing foams of different compositions are used for fire control. As a rule, the foam is produced from aqueous solutions of foamforming concentrates by expansion with air. The concentrates often contain a stabilizing additive as well as the actual foaming agent or foaming agent mixture. Albumin hydrolysates were for many years preferred foaming agents but have become less important recently because of their relatively reduced formation of foam. The foaming agents used in modern fire-extinguishing concentrates are, for instance, alkyl-, aryl- and alkyl aryl-sulphonates, higher alcohol sulphuric acid esters and the sulphates of fatty acid alkanolamines.For instance, German Auslegeschrift 2 933 432 discloses a foam-like fireextinguishing agent for combustible hydrophilic liquids, the agent containing a hydroxycarboxylic acid, an aliphatic carboxylic acid, a salt of an organic or inorganic acid with a metal and an anionic or amphoteric surfactant or an albumin hydrolyzate. A common disadvantage of the known fire-extinguishing agents is that the foam they produce melts on making contact with the burning surface of hydrophilic liquids, such as alcohols, ketones, ethers and esters, so that it becomes impossible to cover the burning surface with foam and thus extinguish the fire. Other agents decompose when stored for a prolonged period or evolve little foam. As a rule, the ability to form foam depends upon the kind of water added. The foam-forming ability of most fire-extinguishing agents is reduced considerably when seawater is added. Also, some ingredients of commercially available fire-extinguishing agents or their decomposition products cause considerable pollution of the environment. It is therefore the object of the invention to overcome these disadvantages and to provide an improved fire-extinguishing concentrate which has good foaming properties and is biologically degradable. The invention accordingly provides a novel fire-extinguishing concentrate containing (in weight %) 3-20% alkylphenolpolyglycolether, 2-18% fatty acid alkanol amide, 6-25% sulphonated polyfluoroalkylbetain, and 20-80% deionised water. The ingredients are in detail as follows: 1. Alkylphenolpolyglycolether These belong to the group of non-ionogenic tensides and are prepared by the condensation of alkylphenyls with ethylene oxide. The alkylphenyl part forms the lypophilic ingredient, and the polyether part the hydrophilic ingredient, of the surfactant. The alkylphenolpolyglycol ethers used in accordance with the invention contain alkyl radicals having 3 to 13 carbon atoms. The corresponding hexyl, heptyl, octyl, nonyl and decyl compounds are preferred. The condensed ethers contain 6 to 20 ethylene oxide units. The compounds having 8 to 12 such units are preferred. The condensate of octyl phenol with 10 ethylene oxide units is particularly preferred:

2. Fatty acid alkanolamides This kind of compound consists of non-ionogenic N-alkylated fatty acid amides which are prepared by the reaction of alkanol amines with fatty acids and which carry esterifiable hydroxy groups in the N-alkyl part. The amides used in the concentrate according to the invention are fatty acid monoand fatty acid di-alkanol amides having the general formula: R CO N(R ) (CH2)6 ȮH in which R denotes the radical of a saturated or unsaturated fatty acid having 6 to 24 carbon atoms. The preferred substances of this kind are derivatives of naturally occurring fatty acids such as caproic acid, capric acid, lauric acid, palmitic acid, stearic acid, coconut oil acid and oleic acid. The diethanol amide of coconut oil acid, N,N-(2-hydroxyethyl)coconut oil acid amide, is particularly preferred. 3. Sulphonated polyfluoroalkylbetain This group of compounds used in the concentrate according to the invention consists of polyfluorated amphotensides, preferably compounds having the general formula:

in which n denotes an integer from 4 to 10, p denotes an integer from 12 to 24 and Me denotes an alkali atom. Sulphonated polyfluoroalkylbetain having the formula:

in which Me represents sodium or potassium are particularly preferred. 4. Deionized water This is water de-ionized by any of the many known processes. 5. Formaldehyde A small quantity of formaldehyde can, if required, be added to the concentrate according to the invention, to serve as a preservative, more particularly for prolonged storage, for instance, in the concentrate form, and also in the readied form of the extinguishing agent according to the invention. The formaldehyde is added in the form of a commercially available approximately 40% solution. The weight percentages for the various ingredients (the preferred range is indicated in brackets) are as follows:

Possibly, 5. Formaldehyde (40% solution) 0.1 3% (0.1 1%) is added. A preferred fire-extinguishing concentrate according to the invention is composed as follows (expressed in weight %): 10% octylphenolpolyglycolether, in the form of a condensate of octylphenol with approximately 10 mol of ethyleneoxide:

10% N,N-(2-hydroxyethyl)coconut oil acid amide, 12.3% sulphonated polyfluoralkylbetain having the formula

67.55% deionized water 0.15% formaldehyde. The invention also relates to a process for the preparation of the fire-extinguishing concentrate hereinbefore described. To this end, the deionized water in a quantity of from 20 to 80 weight % (referred to the total batch) is prepared in a vessel at a temperature of from 15 to 50[deg]C with continuous agitation, whereafter from 3 to 20 weight % of alkylphenolpolyglycolether are added at the same temperature and with agitation, whereafter from 2 to 18 weight % of fatty acid alkanolamide are added in the same conditions. Agitation continues, then from 6 to 25 weight % of sulphonated polyfluoroalkylbetain is added to the resulting mixture. If required, from 0.1 to 3 weight % of formaldehyde are added to the mixture for preservation purposes. Agitation continues until total dissolution of the substances, whereafter the solution is irradiated preferably with polarized light. The concentrate according to the invention is normally mixed with from 90 to 99.5 weight % of water and both fresh water and, without substantial impairment of the foaming properties, seawater can be used for this purpose. The composition according to the invention is classified among the various kinds of fire-extinguishing agents as one of the fluoro-containing agents of the group of the socalled AFFF agents (aqueous film forming foam). The fire-extinguishing agent according to the invention is of use more particularly for controlling fires of liquid or solid hydrocarbons. It can be used as an emulsifier to form foams and in this capacity boost the penetration of water in cellulose materials such as wood, straw, paper, etc. The agent therefore has a wide variety of possible uses, for instance, in the chemical industry, refineries, airports, the plastics industry etc. The action of the agent according to the invention is based on barrier and cooling effects. It also has the advantage that any powder extinguishing agents used previously do not impair the foamforming ability of the product according to the invention. Comparative tests with known AFFF agents showed that the concentrate according to the invention had the following advantages: ' (a) The extinguished products were intensively cooled; (b) The extinguishing capacity of the agent according to the invention is better than that of the known agents at a given concentration; (c) The concentrate according to the invention can be used in very low concentrations without impairment of its extinguishing effects; . (d) The foam produced by the agent according to the invention covers the surface of a liquid hydrocarbon gaplessly and thus obviates the escape of combustible gases; (e) The agent according to the invention does not pollute the environment since all its ingredients are biologically degradable. The concentrate according to the invention can be brought to the place of the fire in dilution with water and, depending upon the place and nature of the fire, by means of portable or transport facilities or it can be used for fixed fire extinguishing systems. The latter can, if required, come into action automatically, for instance, by means of fuses, under the control of optical or thermal sensors, in sprinkler systems and so on.

Example 1 67.55 weight % (referred to the total batch) of deionized water is introduced into a flask having an agitator and a feed funnel. The flask is heated to from 25 to 30[deg]C by a water bath throughout the entire process. 10 weight % of octylphenol polyethylene ether (condensate of octylphenol with 10 mol of ethyleneoxide), then 10 weight % of N,N-(2-hydroxyethyl)coconut oil acid amide, are added with agitation. The mixture is given further agitation, then mixed with 12.3 weight % of sulphonated polyfluoroalkylbetain

whereafter 0.15 weight % of formaldehyde is added and the resulting mixture is agitated until total dissolution of its ingredients. A turquoise-coloured liquid having a viscosity of 98 cP at 20[deg]C is yielded. The liquid has a density of 1.02 and is miscible with water in all proportions. It has an anionic character and its pH value is 8. Its freezing point is 0[deg]C. The concentrate will keep for at least 5 to 6 years and can readily be mixed with water in quantities of from 0.5 to 10 weight %; conveniently, concentrations contain from 2 to 4 weight % of the concentrate.

Example 2 Mixing is performed in the same conditions as described in Example 1. The various ingredients are added in the following proportions:

Weight % Deionized water: 71.25 Octylphenolpolyethylene ether: 1 Fatty acid alkanolamide: 5 Sulphonated polyfluoroalkylbetain: 8.6 Formaldehyde (40%) 0.15 Upon the termination of agitation and complete dissolution of the ingredients, the solution is irradiated with polarized light.

Claims

Claims

1. A liquid fire-extinguishing concentrate, characterised by the following content (in weight %): 3-20% alkylphenolpolyglycolether, 2-18% fatty acid alkanol amide, 6-25% sulphonated polyfluoroalkylbetain, and 20-80% deionised water.

2. A concentrate according to claim 1, characterised by an additional content of 0.1 weight % of formaldehyde.

3. A concentrate according to at least one of claims 1 and 2, characterised in that the alkylphenolpolyglycolether has an alkyl radical having 3 to 13 carbon atoms and contains 6 to 20 ethylene oxide units in the polyglycol part.

4. A concentrate according to at least one of claims 1 to 3, characterised in that the fatty acid alkanol amide is a fatty acid mono- or fatty acid di-alkanol amide and is derived from a fatty acid having 6 to 24 carbon atoms. 5. A concentrate according to at least one of claims 1 to 4, characterised in that the sulphonated polyfluoroalkylbetain corresponds to the general formula:

in which n denotes an integer from 4 to 10, p denotes an integer from 12 to 24 and Me denotes an alkali metal atom.

6. A concentrate according to claim 1, characterised by a content (in weight %) as follows: 10% octylphenol polyglycolether, 10% N,N-(2-hydroxyethyl) coconut oil acid amide,

12.3% of sulphonated polyfluoroalkylbetain having the formula:

67.55% of deionised water, and 0.15% of formaldehyde. 7. A process for the preparation of a liquid fire-extinguishing concentrate according to any of claims 1 to 6, characterised in that from 20-80 weight % of deionised water is prepared with agitation at a temperature of from 15 to 50[deg]C, whereafter from 3 to 20 weight % of alkylphenolpolyglycolether, from 2 to 18 weight % of fatty acid alkanol amide, from 6 to 25 weight % of sulphonated polyfluoroalkylbetain, in that order, and possibly from 0.1 to 3 weight % of formaldehyde are added and the resulting mixture is agitated until total dissolution of the ingredients.

8. A process according to claim 7, characterised in that the added alkylphenolpolyglycolether has an alkyl radical having 3 to 13 carbon atoms and contains 6 to 20 ethylene oxide units in the polyglycol part. 9. A process according to claim 7 and/or 8, characterised in that the added fatty acid alkanol amide is a fatty acid mono- or fatty acid di-alkanolamide and is derived from a fatty acid having 6 to 24 carbon atoms.

10. A process according to at least one of claims 7 to 9, characterised in that the added sulphonated polyfluoroalkylbetain corresponds to the general formula: CnFPCH2((CH2CONH(CH2)3Me2(CH2)3)SO3 in which n denotes an integer from 4 to 10,p denotes an integer from 12 to 24 and Me denotes an alkali metal atom.

11. A process according to claim 7, characterised in that: 10% of octylphenolpolyglycolether, 10% of N,N-2(2-hydroxyethyl) coconut oil acid amide,

12.3% of sulphonated polyfluoroalkylbetain having the formula:

67.55% of deionised water, and 0.15% of formaldehyde all percentages being weight %, are added. 12. A process according to at least one of claims 7 to 11, characterised in that the solution is irradiated with polarised light.