VANDAELE, Geert, Alfons (Fabriekweg 48, Eernegem, B-8480, BE)
| CLAIMS 1. A fire-retardant composition essentially comprising a water-soluble flame extinguishing agent, a swelling agent and a complexing agent and optionally a charring agent and a gelling agent, as well as an aqueous solution of this composition. 2. A fire-retardant composition according to claim 1, characterized in that the flame extinguishing agent includes a phosphate containing agent, preferably an ammonium hydrogen phosphate, more preferably diammonium hydrogen phosphate. 3. . A fire-retardant composition according to claim 1 or 2, characterized in that the swelling agent is selected from the group consisting of guanidine, guanidine hydrogen chloride, urea, glycine and further water-soluble amino acids and derivatives thereof such as amides. 4. A fire-retardant composition according to one or more of claims 1-3, characterized in that complexing agent is selected from the group consisting of ethylenediaminetetraacetic acid and nitrilotriacetic acid and salts thereof.. 5. A fire-retardant composition according to one or more of claims 1-4, characterized in that the charring agent is selected from the group consisting of dextrine, glycerine, inositol, amylose, water-soluble polysaccharides, pentaerythritol, dipentaerythritol and polyalcohols. 6. A fire-retardant composition according to one or more of claims 1-5, characterized in that the gelling agent is selected from the group of partially crosslinked potassium acrylate polymers or analogs in that group. 7. A fire-retardant composition according to one or more of claims 1-6, characterized in that the composition comprises: flame extinguishing agent, 50 - 80 mol% swelling agent, 5 - 40 mol% complexing agent, 1 - 10 mol% charring agent, 0 - 30 mol% gelling agent, 0 - 40 mol%. 8. A method for preparing a fire-retardant composition according to one or more of claims 1-6, characterized in that in an excess of water the agents are dissolved to form an aqueous solution of this composition and the composition itself results from evaporation thereof. 9. A method for preparing a fire-retardant composition according to claim 7, characterized in that to the water in succession optionally a charring agent is added, a flame extinguishing agent, a complexing agent, a charring agent and a gelling agent. 10. A method for preparing a fire-retardant composition according to claim 7 or 8, characterized in that the flame extinguishing agent is an ammonium hydrogen phosphate which is added to the solution in the form of the ammonium hydrogen phosphate and/or in the form of ammonia and phosphoric acid after which the solution is neutralized. |
The invention relates to a fire-retardant composition, and to an aqueous solution of this composition. The invention further relates to a method for preparing such a fire-retardant composition and an aqueous solution thereof. There is a great need for fire-retardant and fire-resistant substances that are effective and can be used on as many different materials as possible. Still being used for this purpose are the naturally occurring carcinogenic asbestos and persistent organic pollutants such as PBDEs (polybrominated diphenyl ether) and PCBs (polychlorinated biphenyl). A further example of a fire-retardant composition are phosphorus compounds which in case of fire react to form polyphosphoric acids and metaphosphoric acids, which form an oxygen barrier layer.
Also organophosphates are used as fire retardants, such as a mixture of organophosphates described in U.S. Patent 4,499,222, but the effectiveness of such a treatment is too variable and not high enough to achieve the amount of fire retardance that is desired. There remains a demand for compositions working more effectively.
A further requirement to be met by the composition to be developed is that it should be environment-friendly. In U.S. Patent 6,911,070, a fire-retardant colloidal dispersion is described of cellulose in water, a charring agent, a swelling agent and a source of phosphoric acid. In the use of such a composition, there is a good chance that gases such as ammonia may be released, which are hazardous to public health. Moreover, the use of a colloidal dispersion entails specific problems as chance of settling and temperature dependent behavior.
The object of the present invention is to provide a composition which is highly effectively fire-retardant, which remains stable over a very long period of time, and is applicable to all kinds of materials and is environment-friendly.
To achieve the object contemplated, the invention provides a composition of the above-mentioned type, characterized in that it essentially comprises a water-soluble flame extinguishing agent, a water-soluble swelling agent, and a water-soluble complexing agent and optionally a water-soluble charring agent, as well as an aqueous solution of this composition. In particular, the flame extinguishing agent includes a phosphate containing agent, preferably an ammonium hydrogen phosphate, more preferably diammonium hydrogen phosphate.
The swelling agent is preferably selected from the group consisting of guanidine, guanidine hydrogen chloride, urea, glycine and further water- soluble amino acids and derivatives thereof such as amides.
The complexing agent is preferably selected from the group consisting of ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid and salts thereof..
The charring agent is preferably selected from the group consisting of dextrine, glycerine, inositol, amylose, water-soluble polysaccharides, pentaerythritol, dipentaerythritol and polyalcohols. The gelling agent is preferably selected from partially crosslinked potassium aery late polymers or analogs in this group.
The chemical composition of the fire-retardant composition according to the invention comprises the following chemical components: flame extinguishing agent, 50-90 mol%, more preferably 60-80 mol% - swelling agent, 5-40 mol%, more preferably 10-30 mol% complexing agent, 0.5-10 mol%, more preferably 1-5 mol% charring agent, 0-30 mol%, more preferably 0-20 mol% gelling agent, 0-40%, more preferably 10-30 mol%.
A further aspect of the present invention provides a method for preparing such a fire-retardant composition, including the steps of dissolving the chemical components in an excess of water to form an aqueous solution of this fire-retardant composition, and isolating the composition proper therefrom through evaporation. Preferably, to the water, in succession optionally a charring agent is added, a flame extinguishing agent, a complexing agent, a swelling agent and a gelling agent.
If the flame extinguishing agent is an ammonium hydrogen phosphate, this can be added to the water both in the form of ammonium hydrogen phosphate and in the form of ammonia and phosphoric acid, or both. The order of adding salt and/or base and acid is not critical here. After that, the solution is neutralized with an inorganic acid such as for instance hydrochloric acid or sulfuric acid.
In the present application, 'agent' should be understood to mean one or more of the group members mentioned: hence, as a complexing agent, for instance, also both EDTA and nitrilotriacetic acid may be used, while in that case the mole percentages mentioned relate to the total of the group members.
The aqueous solution of the composition according to the invention has surprisingly good properties. Material of whatever kind, such as, for instance, metal, plastic, wood, treated with the aqueous solution of the composition and contacted with fire, does not burn and also has extinguishing properties, so that besides extinguishing a fire, also the environment is impregnated and fire will not expand further. The solution proper remains stable for years. Further, it will be clear that the fire- retardant composition and its solution in water meet the Stockholm
Convention on Persistent Organic Pollutants (POPs) in force since 17 May 2004, whose goal is to eliminate persistent organic pollution.
Although the invention has been elucidated hereinabove on the basis of a number of combinations of fire-retardant compositions, it will be clear that the invention is not in any way limited thereto. On the contrary, within the framework of the invention many variations are possible for a person of ordinary skill in the art.
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