VAN DER MEULEN, Erwin (Zuiderdiep 73c, TB Drouwenermond, NL-9523, NL)
Claims
1. Fire-retardant composition consisting essentially of a water-soluble flame- extinguishing agent, an intumescent agent and a complexing agent, and optionally a charring agent, in addition to an aqueous solution of this composition, wherein the intumescent agent is not NaHCC> 3 when a charring agent is not present.
2. Fire-retardant composition according to claim 1, and an aqueous solution of this composition, characterized in that it comprises as flame-extinguishing agent an ammonium hydrogen phosphate, preferably di-ammonium hydrogen phosphate.
3. Fire-retardant composition according to claim 1 or 2, characterized in that the intumescent agent is chosen from the group consisting of guanidine, guanidĪ®ie hydrochloride, urea, glycine and further water-soluble amino acids and derivatives thereof such as amides.
4. Fire-retardant composition according to one or more of the claims 1-3, characterized in that the complexing agent is chosen from the group consisting of ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylene pentaacetic acid, dodecane tetraacetic acid and salts thereof.
5. Fire-retardant composition according to one or more of the claims 1-4, characterized in that the charring agent is chosen from the group consisting of dextrin, glycerin, inositol, amylose, water-soluble polysaccharides, pentaerythritol, dipentaerythritol and polyalcohols.
6. Fire-retardant composition according to one or more of the claims 1-5, characterized in that the composition consists of: - flame-extinguishing agent, 50-95 mol%
- intumescent agent, 5-40 mol% - complexing agent, 0.3-10 mol%
- charring agent, 0-30 mol%.
7. Method for preparing a fire-retardant composition according one or more of the claims 1-6, characterized in that the agents are dissolved in an excess of water for the purpose of forming an aqueous solution of this composition, and the composition itself is isolated therefrom.
8. Method for preparing a fire-retardant composition according to claim 7, characterized in that a charring agent (optional), a flame-extinguishing agent, a complexing agent and an intumescent agent are added successively to the water.
9. 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.
10. Method for making a material fire-retardant, characterized in that the material is treated with a fire-retardant composition or a solution thereof as defined in one or more of the claims 1-6.
11. Method according to claim 10, characterized in that the material is painted with paint mixed with the fire-retardant composition or a solution thereof. |
Fireproof and ftre-retardant composition
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 fireproof and fire-retardant substances which are effective and can be applied to as many different materials as possible. Still applied for this purpose are the naturally occurring carcinogenic asbestos and persistent organic pollutants such as PBDEs (polybrominated diphenyl ethers) and PCBs (polychlorinated biphenyls). A further example of a fire-retardant composition is formed by phosphor compounds, which in the case of fire react to form polyphosphoric acids and metaphosphoric acids which form an oxygen-excluding layer.
Organophosphates are also applied as fire-retardant, such as a mixture of organophosphates as described in the US patent 4,499,222, although the effectiveness of such a treatment is too variable and not great enough to achieve the desired measure of fire retardance. There continues to be a demand for compositions which work more effectively.
A further requirement laid down for a composition to be developed is that it must be environmentally-friendly. Described in US patent 6,911 ,070 is a fire-retardant colloidal dispersion of cellulose in water, a charring agent, an intumescent agent and a source of phosphoric acid. When such a composition is applied, there is a great chance lhat gases such as ammonia can be released which represent a danger to public health. Furthermore, the use of a colloidal dispersion entails specific problems, such as the chance of deposition and temperature-dependent behaviour. WO 9100326 describes a fire-retardant and smoke-retardant composition wherein NaHCO 3 is applied as intumescent agent, wherein CO 2 is released during use, this not being desirable from an environmental viewpoint. WO 2004/112907 describes a foaming fireproof composition comprising as essential component a high molecular weight acid polymer with the purpose of stabilizing the foaming composition.
The present invention has for its object to provide a composition and the aqueous solution thereof which has very effective fire retardance, remains stable over a very long
period of time, can be applied to all sorts of possible materials and is environmentally- friendly.
In order to achieve the intended object the invention provides a composition of the type stated in the preamble, characterized in that it consists essentially of a water- soluble flame-extinguishing agent, a water-soluble intumescent agent and a water- soluble complexing agent, and optionally a water-soluble charring agent, in addition to an aqueous solution of this composition wherein the intumescent agent is not NaHCO 3 when a charring agent is not present. The flame-extinguishing agent particularly comprises a phosphate-containing agent, preferably an ammonium hydrogen phosphate, more preferably di-ammonium hydrogen phosphate.
The intumescent agent is preferably chosen from the group consisting of guanidine, guanidine hydrochloride, urea, glycine and further water-soluble amino acids and derivatives thereof such as amides.
The complexing agent is preferably chosen from the group consisting of emylenediarninetetraacetic acid (EDTA), nitrilotriacetic acid, diethylene pentaaacetic acid, dodecane tetraacetic acid and salts thereof.
The charring agent is preferably chosen from the group consisting of dextrin, glycerin, inositol, amylose, water-soluble polysaccharides, pentaerythritol, dipentaerythritol and polyalcohols. The chemical composition of the fire-retardant composition according to the invention consists essentially of the following chemical components:
- flame-extinguishing agent, 50-95 mol%, preferably 50-90 mol%, more preferably 60-90 mol%, especially 60-80 mol%,
- intumescent agent, 5-40 mol%, more preferably 10-30 mol%; - complexing agent, 0.3-10 mol%, preferably 0.5-10 mol%, more preferably 0.5-5 mol%, especially 1-5 mol%;
- charring agent, 0-30 mol%, more preferably 0-20 mol%.
A further aspect of the present invention provides a method for preparing such a fire-retardant composition, comprising of dissolving the chemical components in an excess of water for the purpose of forming an aqueous solution of this fire-retardant composition, and isolating the composition itself therefrom, for instance by evaporation.
A charring agent (optional), a flame-extinguishing agent, a complexing agent and an intumescent agent are preferably added successively to the water.
If the flame-extinguishing agent is an ammonium hydrogen phosphate, it can then be added to the water in the form of ammonium hydrogen phosphate as well as in the form of ammonia and phosphoric acid, or both. The sequence of adding salt and/or base and acid is not critical here. If necessary, the solution is neutralized with an inorganic acid, such as for instance hydrochloric acid or sulphuric acid. The composition according to the invention in solid form can be isolated from such a solution in known ways, for instance by means of evaporation. It will be apparent that, in addition to a flame-extinguishing, intumescent, complexing and charring agent, the composition prepared in this way can also comprise substances such as salts (generally inorganic such as for instance ammonium chloride). The mole percentages stated in the present patent application have been determined on the basis of the quantity present of flame- extinguishing, intumescent, complexing and charring agent. In the present application an agent must be understood to mean one or more of the stated group members; nitrilotriacetic acid and/or diethylene pentaacetic acid and/or dodecane tetraacetic acid can for instance thus be applied as complexing agent in addition to EDTA, wherein the stated mole percentages in that case relate to the total of the applied group members. This is therefore also the case for the flame-extinguishing, intumescent and charring agents. Fire-retardant is further also understood to mean fireproof, and vice versa. It will also be apparent that the term composition must also be understood to mean a plurality of possible mixtures.
The aqueous solution of the composition according to the invention has surprisingly good properties. Material of any type whatsoever, such as for instance metal, plastic, wood, paper, cardboard, substances used as floor covering or curtain, treated with the aqueous solution of the composition according to the invention and placed into contact with fire, does not burn. Both concentrated and more diluted solutions, wherein a range of about 0.1-5 molar of phosphate must be envisaged as being present, are suitable for bringing about fireproof and fire-retardant properties. Treatment must also be interpreted broadly within the scope of the invention. This treatment can also take place indirectly, for instance by mixing paint with a solution of
the composition according to the invention, or by applying the composition itself and this paint to the material by means of painting. The addition of surface-active substances can be advantageous, especially for such an application; it will be apparent that a solution of the composition according to the invention with such an additive also forms part of the invention. A fireproof composition according to the invention can also be added during the production process for a material, such as for instance in the preparation of concrete.
The solution itself according to the invention remains stable for years. It will further be apparent that the fire-retardant composition and the solution thereof in water complies with the Stockholm Convention on 'Persistent Organic Pollutants' (POPs), in force since 17 May 2004 with the purpose of eliminating persistent organic pollutants.
The invention is further elucidated on the basis of a number of examples.
Example 1 Preparation of fire-retardant solution and composition
Added successively to 211 ml water were 21 gr 46% m/m urea, 75 gr di- ammonium hydrogen phosphate, 45 ml phosphoric acid (75% m/v), 73 ml ammonia (25% m/v), 16 ml hydrochloric acid (30% m/v), 8.2 ml glycerin (sw 1.26) and 8.3 ml EDTA (39% m/v). The resulting 400 ml of neutral fire-retardant solution (A) is ready for use.
Solution A was reduced by evaporation until all the water was evaporated. The result is an almost white solid composition which is soluble in water.
Example 2
Preparation of fire-retardant solution with different sequence of addition of ingredients
Added successively to 220 ml water were 150 gr di-ammonium hydrogen phosphate, 22.5 ml phosphoric acid (75% m/v), 36.5 ml ammonia (25% m/v), 16 ml
hydrochloric acid (30% m/v), 8.3 ml EDTA (39% m/v) and 21 gr 46% m/m urea. The resulting 400 ml of fire-retardant solution (B) is ready for use.
Example 3 Preparation of fire-retardant solution with low concentration
Added successively to 380 ml water were 2 gr 46% m/m urea, 14 gr di- ammonium hydrogen phosphate, 2.5 ml phosphoric acid (75% m/v), 4 ml ammonia (25% m/v), 2 ml hydrochloric acid (30% m/v), 1 ml glycerin (sw 1.26) and 1 ml EDTA (39% m/v). The resulting fire-retardant solution (C) is ready for use.
Example 4 Application of fire-retardant solutions to cotton
A piece of cotton with a thickness of 0.8 mm was immersed in solution A. After drying the piece of cotton was hung at a distance of 10 cm &om a Bunsen burner. The temperature of the cotton in the heart of the flame amounted to 500 0 C. The cotton did not burn but was charred. It was possible without problem to hold a hand 2 cm from the rear side of the cotton. Solution A was diluted five times. The same result was achieved with this diluted solution.
Repetition of this experiment with use of solution C also gave the same result.
Example 5 Application of fire-retardant solutions to wood
Fire-retardant solution A was mixed with paint, applied to wood and held in a burner. The wood to which the treated paint was applied did not burn. It was possible to see under a microscope that a thin foam layer had formed.
Although the invention is elucidated above on the basis of a number of different fire-retardant compositions and the use thereof in making materials fireproof, it will be apparent that the invention is by no means limited thereto. On the contrary, many variations are possible within the scope of the invention for a person average skilled in the art.