The invention relates to the field of aqueous fire resistant materials and coating agents for improving fire resistance of organic materials.

Background art

Known is US4804482, describing an aqueous solution of citric acid in which the amount of citric acid is 300-350 grams/liter, and an equimolar ratio of Na and K ions is 0.6-1.0: 100, wherein the Na ions are obtained from sodium carbonate and K ions from potassium carbonate . This solution is suitable for fire extinguishing and for the treatment of organic materials to provide fire resistance.

Known is US2005116193, describing a mixture comprising 10-50% by weight of the fire

extinguishable component, 3-15% by weight of organic acid, 0.01 to 5% by weight of surfactant, and water of 100% by weight. Also described is a method of making a mixture comprising dissolving 10- 50% by weight of a fire extinguishing component in water, dissolving from 3 to 15% by weight of an organic substance and then 0.01 to 5% by weight of a surfactant and allowing the mixture to stand for at least 24-48 hours to stabilize the mixture. The fire extinguishing component may include, among many other components, potassium carbonate or urea (carbamide); its amount of less than 10% by weight results in poor flame resistant properties of the mixture; more than 50% by weight causes the sediment in the mixture. Among many acids, citric acid 3-15 weight percent may be used - if the amount of citric acid is outside this range, the mixture is not neutral. This can be considered as closest prior art. Surprisingly, an aqueous mixture with the same or better fire resistant and fire extinguishing properties, in which the amount of citric acid compared to potassium carbonate in the solution is the same or greater.

Summary of the invention

The goal of the invention is achieved by a composition obtained from the following ingredients in the following proportions: potassium carbonate (K ₂ C0 ₃ ) 10-30 parts by weight, preferably 18.5-20 parts by weight; citric acid (C ₆ H ₈ 0 ₇ ) 10-30 parts by weight, preferably 18.5 to 20 parts by weight; urea (H ₂ NCO-NH ₂ ), preferably from 3 to 15 parts by weight, more preferably 8 to 10 parts by weight; and water (H ₂ 0) 100 parts by weight.

The prepared composition has a pH of preferably 9-9.5 and a density of 1.16-1.17 kg / I.

The composition may further comprise ethanol (C ₂ H ₅ OH) or methanol (CH ₃ OH) to improve the disinfecting properties of the composition. Also, iron phosphate (Fe (H ₂ P0 ₄ ) ₃ ) and boric acid (BH ₃ 0 ₃ ) disinfectant properties can be added to the composition. 3-4 grams of ethanol or methanol, 2-3 grams of iron phosphate and 1-2 weight percent of boric acid are added per liter of solution.

The object of the invention is also achieved by a method of dissolving powdered citric acid in water, dissolving powdered potassium carbonate in water, dissolving the urea in water, and mixing the resulting aqueous solutions. Preferably, 185 to 200 grams of powdered citric acid are dissolved in 400 ml of water, from 185 to 200 grams of powdered potassium carbonate dissolved in 400 ml of water and 80-100 g of urea dissolved in 200 ml of water, and the resulting aqueous solutions are mixed.

The invention also relates to the use of a composition for increasing the fire resistance of an organic material, for example, wood. The present invention is now illustrated by the following examples, which do not limit the scope of the invention in any way.

Examples of the invention

According to a first embodiment of the invention, a composition is prepared using the ingredients powdery citric acid, powdered potassium carbonate and urea. All starting materials are first dissolved in an appropriate amount of water, and then the resulting aqueous solutions are mixed.

Alternatively, powdered citric acid and powdered potassium carbonate are mixed and dissolved in a appropriate amount of water and then urea is added.

According to another embodiment of the invention, a composition comprising the following is made: potassium carbonate 20 parts by weight;

citric acid 20 parts by weight;

urea 10 parts by weight; and

water 100 parts by weight.

In an another embodiment of the invention, a composition comprising the following is made:

15 potassium carbonate 18.5 parts by weight; citric acid 20 parts by weight;

urea 8 parts by weight; and

water 100 parts by weight.

According to a third embodiment of the invention, a composition comprising the following is made: potassium carbonate 20 parts by weight;

citric acid 18.5 parts by weight;

urea 8 parts by weight; and

water 100 parts by weight.

In a fourth embodiment of the invention, a composition comprising the following is made:

potassium carbonate 18.5 parts by weight;

citric acid 20 parts by weight;

urea 10 parts by weight; and

water 100 parts by weight.

The composition is preferably prepared as follows: 185 g to 200 g of powdered citric acid is dissolved in 400ml of water

185 g to 200 g of powdered potassium carbonate in dissolved in 400 ml of water

80 to 100 g of urea is dissolved in 200 ml of water, and

water solutions are mixed together.

The composition may also be prepared as follows: 185 g to 200 g powdered citric acid, and potassium carbonate is mixed and the prepared powder is dissolved in 1000 ml of water and 80 g to 100 g of urea is added.

The desired amount of useful additives is added to the finished composition, for example 10-15 g ethanol or methanol per litre of solution, 2-3 g of iron phosphate per litre of solution and 1-2% by weight of boric acid. The fire resistant properties of the composition are due to the fact that when the temperature rises above 175 °C, the citric acid decomposes into aconite acid and the latter decomposes into water and carbon dioxide. The composition is suitable for use as a wood impregnation to increase fire resistance, as well increasing the fire resistance of wood, wood-based materials (paper, cardboard), fabrics and the like. Wood impregnated with a composition corresponds to fire resistance class A2, B, si and dO.

When the wood surface is heated, the top layer of the treated surface begins to become brownish and expands ("bubbles") and thus prevents further spread of fire into the material.

The composition is also suitable for use as a fire barrier for forest and fires, and the like to limit harmful proliferation. In this case, the composition is sprayed around the fire are such as the ground, trees, buildings, so that the fire could not be penetrated by the fire.

The quantities of the above ingredients are optimized. Reduce the amount of potassium carbonate among the starting materials for the remainder of the range offered the fire-resistance properties of the composition deteriorate. The amount of potassium carbonate increase from the range offered up to the same amount of other starting materials the density of the composition increases, the absorption of the material decreases and thus deteriorates fireproof properties. Reducing the amount of citric acid also worsens fireproofing properties, including reducing the effect of expansion of the composition (bubble effect) when heating.

Increasing the amount of citric acid increases the density and the surface of the product can get a white cover. Decreasing the amount of urea results in a deterioration of the solubility and composition absorption into material. Increasing the amount of urea results again in increased density and in decreased absorption, but also the composition and thus also the treated surface acquires a yellowish color (the composition with ingredients according to invention is colourless).