WO2022079101A9

WO2022079101A9 - Fire extinguishing compositions and method of preparation thereof

Info

Publication number: WO2022079101A9
Application number: PCT/EP2021/078310
Authority: WO
Inventors: Vlatko TASEVSKI; Ilija MATOVSKI
Original assignee: Vt Production Dooel Skopje
Priority date: 2020-10-14
Filing date: 2021-10-13
Publication date: 2022-11-10
Also published as: EP4255588A1; WO2022079101A1; GB2600679A; GB202016281D0

Abstract

The invention solid fire extinguishing composition, comprising: a phosphorous based component; a viscosity-adjusting component; optionally, one or more further additives; wherein when the solid composition is mixed in water at a concentration of 12.5 % w/w, the viscosity of the solution is at least 100 mPas at 20 °C. The compositions show excellent fire control properties, and are particularly suitable for use in the control of Class A fires, especially those involving wood, coal, textile, straw, grass, forest and the like.

Description

FIRE EXTINGUISHING COMPOSITIONS AND METHOD OF PREPARATION

THEREOF

Field and background

1. Technical Field

The present invention relates to compositions for use in fire control, method of preparation thereof and use of such compositions in fire control.

2. Background art

Inadvertent and uncontrolled fires are most dangerous and undesirable events. Fire need four basic elements to initiate - oxygen, heat, fuel and burnable (flammable) materials. Fire extinguishers work by eliminating one of these elements to a point where fire is not viable anymore. There have been many technological advances in recent years to mitigate these hazardous fires.

There are six classes of fire - class A, B, C, D, E and F. Most of the fire extinguishers are classified according to the type of fire based on the component of the extinguishing agent. For example - water extinguishers are most suitable for class A type fire - those caused by solid materials such as paper, wood, textiles, coal, straw, grass etc.

Amongst many fire extinguishers, water extinguishers are one of the most cost-effective means to combat class A fires. Water works by reducing the temperature below combustion or ignition temperature of the burning material.

Prior teachings disclose dry powder fire extinguisher compositions containing cellulose and ammonium/ sodium phosphate along with other components. Few other disclose cellulose based preparations in combination with alkali metal, borate and phosphates. However, a limitation of such fire extinguishing compositions is that they do not seem to be efficient and a residue ember is left which has the ability to rekindle a fire. Moreover, the viscosity of fire extinguishing agents/ compositions reduces at high temperature which increases its extinguishing time. For such reasons, it is useful to have a composition which prevents afterglow, enhances the fire extinguishing effect and improves water performance, thereby making fire extinguishing composition efficient and cost effective.

The present invention is directed towards composition fulfilling such criteria i.e. boosting the fire extinguishing effect of water and prevent afterglow. Particularly, the compositions of present invention work by enhancing the fire extinguishing effect of water by giving it an anticatalytic effect that prevent, retard, suppress or extinguish fire.

SUMMARY OF THE INVENTION

In one of the embodiments, the present invention relates to a solid fire extinguishing composition, comprising: a phosphorous based component; a viscosity-adjusting component; and optionally, one or more further additives; wherein when the solid composition is dissolved in water at a concentration of 12.5 %, the viscosity of the solution is at least 100 mPas at 25 °C as measured by the Brookfield method.

According to a second embodiment, the present invention relates to an aqueous composition, comprising i. solid fire extinguishing composition according to the invention; ii. optionally, one or more further additives usual in fire extinguishing compositions; and iii. balance water.

According to a third embodiment, the present invention relates to the use of a solid fire extinguishing composition or an aqueous composition according to the first or second aspects for extinguishing or suppressing a fire. According to a fourth embodiment, the present invention relates to the use of a solid fire extinguishing composition or an aqueous composition of the invention as a flame retardant.

According to a fifth embodiment the invention relates to a flammable material impregnated with a solid fire extinguishing composition of the invention.

According to a sixth embodiment the invention relates to a method of preparing the composition as claimed in any of the preceding claims, wherein the method comprises: i) grinding all the components as defined in claim 1 ; ii) drying the resulting mixture of step i) below 4% humidity; and iii) homogenizing the mixture obtained in step ii) to obtain the composition.

The fire -preventing composition of present invention are useful in suppressing, extinguishing, and/or retarding the progression of a fire. Surprisingly, it has been found that composition of present invention comprising a flame -retardant component, an additive, an alkali compound and/or an anionic surfactant compound have an effective and surprising effect on control of fire.

Particularly, the fire extinguishing composition of present invention is directed to extinguishers of class A, B, C and E (up to 1000 volts) fires and method of preparing the same. The fire extinguishing composition present invention overcome the abovementioned disadvantages of prior art and provides a useful commercial choice with high extinguishing efficacy, excellent safety performance, and high utilization ratio.

Detailed Description of the Preferred Embodiments "Composition" and like terms mean a mixture or blend of two or more components as referred to herein.

The term "fire resistant" means resistant or retardant to flaming or burning or smoldering combustions. The term "fire-retardant component" refers to a chemical substance or mixture that reduces or controls or retards or prevents or suppresses flammability or smoldering of a material. The term “fire control” means fire prevention or fire mitigation or fire inhibition or the like. “Fire extinguishing” means have the ability to prevent, reduce or retard combustion when applied to a fire.

The solid fire extinguishing composition of the invention comprises a phosphorous based component. Phosphorus-based components as a class exhibit moderate-to-low toxicity as compared to haloalkyl or aryl phosphates. In a preferred embodiment, the phosphorus- based components are selected from the group consisting of monoammonium phosphate, diammonium phosphate, di ammonium pyrophosphate, tri ammonium pyrophosphate, tetraammonium pyrophosphate, ammonium polyphosphate, substituted ammonium polyphosphate, amide polyphosphate, melamine polyphosphate, ammonium dihydrogenphosphate or mixtures thereof. In a very preferred embodiment, the phosphorus-based flame retardant is monoammonium phosphate.

Monoammonium phosphate can either be unmodified monoammonium phosphate, (NH₄XH₂PO₄), or modified monoammonium phosphate, modified with up to 20% of ammonium polyphosphate [NH₄ P0₃]_n(0H)₂, having the formula (NFLt)n₊₂Pn0₃n_+i. In a particularly preferred embodiment, modified monoammonium phosphate is present in an amount of from 80 to 99 % w/w, preferably 85 to 95 % w/w, such as about 92.6 %.

In one preferred embodiment, the Phosphorus-based components includes at least an alkali metal tripolyphosphate, preferably sodium tripolyphosphate, NasPsOio. Preferably, sodium tripolyphosphate is present in an amount of from 0.1 to 5 % w/w. More preferably, sodium tripolyphosphate is present in an amount of from 0.5 to 2.5 % w/w, such as about 1 %. Preferably, the phosphorous based component is present in the fire-fighting composition in an amount of about 75% to about 95%, and preferably about 80% to about 95%, by weight of the composition. To achieve the full advantage of the present invention, the composition contains about 90 to 95%, by weight of the phosphate compound, preferably monoammonium phosphate (MAP).

The solid fire extinguishing composition further contains a viscosity-adjusting component in the amount of from 1% to 10% by mass percentage. The inclusion of this additive has the result that the when the solid fire extinguishing composition is mixed with water, the resultant mixture has an increased viscosity (relative to pure water). In particular, the resultant aqueous mixture has a viscosity of at least 100 mPa.s (centipoise) at 20 °C when mixed with water in an amount of 12.5 % w/w. More preferably, the resultant aqueous mixture has a viscosity of at least below about 3000 mPa.s, and more preferably below about 2000 mPa.s. Thus, fire extinguishing composition typically are of a viscosity between 80 to 250 mPa.s. The particular viscosity depends on the particular thickener incorporated in the composition, which imparts rheological properties.

The viscosity-adjusting component is preferably selected from the group consisting of one or more of substituted or non-substituted cellulose derivatives such as methyl cellulose, ethyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxypropyl cellulose, and anionic (salt) forms such as carboxymethyl cellulose sodium, dihydroxypropyl cellulose ether or mixture thereof. The additive works as a thickening agent and/or as a stabilizer. In a very preferred embodiment, the additive is sodium carboxymethyl cellulose. The additive helps in achieving an approved level of flame and smolder resistance.

Preferably, the viscosity-adjusting component is present in the fire-fighting composition in an amount of about 1% to about 10%, and preferably about 2% to about 8%, by weight of the composition. More preferably, the cellulose is present in an amount of about 3% to about 7% by weight. In very preferred embodiment, the cellulose is sodium carboxymethyl cellulose.

In an alternative embodiment, the fire extinguishing composition of the present invention includes at least one and optionally more than one surfactant. Preferably, the surfactant is an anionic surfactant. Suitable exemplary anionic surfactants include sulfate anionic surfactants such as sodium lauryl ether sulfate, sodium lauryl sulfate, sodium decyl sulfate, sodium octyl sulfate, ammonium lauryl sulfate, sodium lauryl sulfate, sodium tridecanol ether sulfate etc. A preferred surfactant is sodium laureth sulfate. Preferably, the surfactant is present in an amount of about 0.1-10 % by weight. More preferably, the anionic surfactant is present in an amount of 0.5-5%, such as about 3 %.

In one of the embodiments, the composition comprises a colorant or coloring agent. The use of the coloring agent in the composition is to visibly identify combustible substances. This essentially precludes the dual application of the composition to combustible objects by providing a coloring effect of the coloring agent.

The coloring agent can be a pigment or a dye. The amount of coloring agent used in the composition of the present invention is such that it is sufficient to impart a color which is visible to naked eyes. For instance, from the tone and intensity of the color of the treated combustible objects, fire fighters can determine whether enough amount of the firefighting composition has been applied to the combustible objects. Preferably, the amount of coloring agent is in the range of 0-5% by weight.

The compositions of the present invention are manufactured in powdered form for a later use in water. Preferably, the compositions of the invention are made to be mixed with water, where they may form solutions, suspensions or emulsions. Particularly, the present invention relates to compositions adapted in dry powdered form, to be mixed with water at a later stage. More preferably, the dry powdered composition is to be readily dissolved in water for use on site with a rapid dissolution profile, thereby improving water’s fire extinguishing capacity.

In a further aspect, the invention relates to an aqueous composition, comprising a solid fire extinguishing composition as disclosed elsewhere herein. This aqueous composition may itself be applied to fires, solid composition makes the aqueous composition better adhere to the burning matter which increases its active surface, thus increasing the efficacy in extinguishing the fire and decreasing the total volume required.

The solid fire extinguishing composition increases water density and viscosity which increases the precision of water application during fire extinguishing (especially when applied from the air). Water penetration through burning fuel (e.g. vegetation) increases and can more easily reach lower levels of fire where embers are created.

The solid fire extinguishing composition can be prepared and stored in a powder form having up to 5 years shelf life. The final product (dry powdered form mixed with water) can be stored up to 12 months under storage conditions.

The fire extinguishing composition of the present invention is stable in performance, easy for long-term storage, non-toxic, and has excellent environmentally friendly properties.

Optional embodiments

A fire-fighting composition of the present invention also can include obvious optional ingredients known to persons skilled in the art. Each optional ingredient, if present at all, is in a sufficient amount to perform its intended function without adversely affecting the composition or its use as a fire prevention, suppressing, retarding, or extinguishing agent. For example, the composition can include one or more of a viscosity modifier, a dispersant, a pH modifier, and a surfactant.

Method In one further embodiment, the invention provides a method of making a fire extinguishing composition as identified herein i.e. in dry powder form and in liquid/ aqueous form.

The method comprises: grinding the components - modified cellulose formulation, modified phosphorus- based component and alkali metal tripolyphosphate; drying the resulting mixture of step i) below 4% maximum acceptable humidity; and homogenizing the mixture obtained in step ii)

The composition of the present invention in aqueous form is used by applying (spraying or aerial application) the composition to objects that are already burning, or by applying the composition that are in danger of burning, such as foliage, trees, a building, or other structures near a burning building. In this way, the composition can be used both to extinguish and suppress fires and to retard and prevent fires from spreading.

The solid composition can be applied directly to fires, e.g. in a dry powder fire extinguisher.

Fires are typically categorized according to the following scheme:

Class A - fires involving solid materials such as wood, paper or textiles.

Class B - fires involving flammable liquids such as petrol, diesel or oils.

Class C - fires involving gases.

Class D - fires involving metals.

Class E - fires involving live electrical apparatus.

Class F - fires involving cooking oils such as in deep-fat fryers.

The invention encompasses methods of controlling fires of all these types using the solid and aqueous fire extinguishing compositions disclosed. The compositions are particularly suitable for use in the control of Class A fires, especially those involving wood, coal, textile, straw, grass, forest and the like.

Methods of applying the compositions (solid and aqueous) of the invention will be known to the skilled person. Particularly, they may be applied from hand-held or machined- mounted fire extinguishers using pressurized gas or other propelling means, or dropped or sprayed from aircraft over larger fires.

Further, the compositions of the invention may be applied to flammable materials to render them flame-proof or flame-retardant. Fabrics, paper, wood, foam and plastics may be so treated.

Examples

The fire extinguishing composition of the present invention is further described through the detailed examples below.

EXAMPLE 1

A composition according to the invention is prepared, having the following components:

Modified cellulose (sodium carboxymethyl cellulose) 6.2 g Modified mono-ammonium phosphate MAP (NH₄)_n+2P_n0_3n+i 92.6 g Colour 0.2 g;

Sodium tripolyphosphate Na^PsO lg.

The following process was used

1. The solid components were combined, and ground until desired granulation is achieved.

2. The composition was dried to below 2% humidity

3. The dried composition was homogenized and packaged.

The composition could be stored for five years without decomposition.

EXAMPLE 2

Modified cellulose (sodium carboxymethyl cellulose) 6.2 g Modified mono-ammonium phosphate MAP (NH₄)_n+2P_n0_3n+i 89.6 g Sodium laureth sulfate CH₃(CH₂)n(0CH₂CH₂)_n0S0₃Na 3 g Colour 0.2 g;

Sodium tripolyphosphate NasPsOio lg. A similar process to Example 1 was used.

EXAMPLE 3

The composition of Examples 1 and 2 were mixed with water in an amount of 12.5 % w/w. The resultant aqueous composition had a viscosity of 200 mPa.s and was suitable for extinguishing Class A burning wood fire.

While the present invention has been shown and described with reference to examples given in the description, these examples and embodiments are considered as illustrative and not restrictive of scope of the present invention. Moreover, it will be understood by those skilled in the art that various changes and obvious modification in forms and details may be made without departure from the true spirit and scope of the present invention.

Claims

1. A solid fire extinguishing composition, comprising: a phosphorous based component; a viscosity-adjusting component; and optionally, one or more further additives; wherein when the solid composition is mixed in water at a concentration of 12.5 % w/w, the viscosity of the solution is at least 100 mPas at 20 °C.

2. The composition as claimed in claim 1, wherein the phosphorous based component is selected from the group consisting of monoammonium phosphate, di ammonium phosphate, di ammonium pyrophosphate, tri ammonium pyrophosphate, tetraammonium pyrophosphate, ammonium polyphosphate, substituted ammonium polyphosphate, amide polyphosphate, melamine polyphosphate, ammonium dihydrogenphosphate, sodium tripolyphosphate or mixtures thereof.

3. The composition according to claim 1 or 2, wherein the phosphorous based component comprises at least monoammonium phosphate.

4. The composition according to any preceding claim, wherein the phosphorous based component comprises at least modified mono-ammonium phosphate (NH4)h+2Rhq3h+1·

5. The composition according to any preceding claim wherein the phosphorous based component comprises at least sodium tripolyphosphate.

6. The composition according to any preceding claim wherein the modified phosphorous based component is present in an amount of about 75% to about 95% by weight, preferably about 80% to about 95%, by weight and more preferably about 90 to 95%, by weight.

7. The composition according to any preceding claim, wherein the viscosity adjusting component is a modified cellulose.

8. The composition as claimed in claim 7, wherein the modified cellulose is selected from the group consisting of methyl cellulose, ethyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxypropyl cellulose, and anionic (salt) forms such as carboxymethyl cellulose sodium, dihydroxypropyl cellulose ether or mixtures thereof.

9. The composition according to claim 8 wherein the modified cellulose is carboxymethyl cellulose sodium.

10. The composition as claimed in any one of claims 7 to 9, wherein the modified cellulose formulation is present in an amount of from 1 to 10% by weight.

11. The composition according to any preceding claim further comprising a surfactant.

12. The composition according to claim 11, wherein the surfactant is present in an amount of about 0.1-10% by weight.

13. The composition according to claim 11 or 12, wherein the surfactant is an anionic surfactant.

14. The composition according to claim 13, wherein the anionic surfactant is selected from the group consisting of sodium dodecyl sulfate, sodium myreth sulfate, sodium pareth sulfate, magnesium laureth sulfate, sodium dodecylbenzenesulfonate, sodium lauryl ether sulfate, sodium lauryl sulfate, sodium decyl sulfate, sodium octyl sulfate, ammonium lauryl sulfate, sodium tridecanol ether sulfate and sodium laureth sulfate.

15. The composition according to any preceding claim, further comprises a coloring agent selected from a pigment or a dye, present in an amount of 0-5% by weight.

16. The composition according to any preceding claim, wherein the composition is a dry powder composition adapted to be mixed with water to produce an aqueous composition.

17. An aqueous composition, comprising i. solid fire extinguishing composition according to any one of claims 1 to 16; ii. optionally, one or more further additives usual in fire extinguishing compositions; iii. balance water.

18. An aqueous composition according to claim 17 wherein the solid fire extinguishing composition is present in an amount of from 5 to 20 % by weight, preferably from 10 to 15 % by weight.

19. The use of a solid fire extinguishing composition according to any one of claims 1 to 16 or an aqueous composition according to claim 16 or 17 for extinguishing or suppressing a fire.

20. The use according to claim 19 wherein the fire is a class A fire.

21. The use of a solid fire extinguishing composition according to any one of claims 1 to 16 or an aqueous composition according to claim 16 or 17 as a flame retardant.

22. A flammable material impregnated with a solid fire extinguishing composition according to any one of claims 1 to 16 or an aqueous composition according to claim 16 or 17.

23. A method of preparing the composition as claimed in any of the preceding claims, wherein the method comprises: i) grinding all the components as defined in claim 1 ; ii) drying the resulting mixture of step i) below 4% maximum acceptable humidity; and iii) homogenizing the mixture obtained in step ii) to obtain the composition.

24. The method as claimed in claim 23, wherein the components includes a coloring agent and/or an anionic surfactant.