EP0639995A1

EP0639995A1 - Compositions useful for preventing and/or combatting fire

Info

Publication number: EP0639995A1
Application number: EP93911824A
Authority: EP
Inventors: Jacques Baudouin; Eric Issartel
Original assignee: Lafarge Nouveaux Materiaux SA
Current assignee: Lafarge Nouveaux Materiaux SA
Priority date: 1992-04-30
Filing date: 1993-04-26
Publication date: 1995-03-01
Also published as: FR2690627A1; WO1993022000A1; CA2134688A1

Abstract

The present invention relates to compositions useful for preventing and/or combatting fire as well as to the application of said compositions for preventing and/or combatting fire. The invention discloses a concentrated composition useful after dilution and dissolution or dispersion in a substantially aqueous medium for preventing and/or combatting fire, said composition comprising a clay, optionally a retardant agent, one or a plurality of corrosion inhibitor(s), and anticryptogamic agent and/or a dye, and characterized in that: a) it contains fibres of vegetable origin comprising a majority of natural cellulose fibres and, b) the quantity of said fibres with respect to the whole (fibres + clay) is between 10 and 90 % (by weight).

Description

COMPOSITIONS USEFUL FOR FIRE PREVENTION AND / OR CONTROL

The present invention relates to compositions useful for preventing and / or fighting fire.

The invention also relates to the application of said compositions to the prevention and / or the fight against fire.

The devastating nature, both for the environment and the economy in general, of uncontrolled fire and, in particular of forest, coppice, brush and scrubland fires remains a major concern, the risk for people living staying or intervening in these areas no longer needs to be demonstrated. It has been well known to the public for a long time that it is sometimes possible to stop or prevent the development of such a disaster, either by cooling the combustible material on the site, or by cutting it off. any source of oxidizer promoting its combustion, ie by combining the two types of intervention. It is thus quite usual to use water on sites on fire, the main well-known functions of which are as follows:

- cooling the treated medium;

- Provide a localized isolation effect of the flame site by cutting it, at least temporarily, from its oxidant source as soon as it is vaporized, by expelling the air present by the gas volume thus developed and by preventing less momentarily, the air to renew itself.

Although water remains the preferred means of fighting fire, many previous proposals have aimed to reinforce its flame-retardant effects by the introduction of various agents or ingredients capable of inducing one and / or the other of the following processes. :

- favor the penetration of water into the combustible materials to be protected,

- favor the formation of larger layers of water on the surfaces to be protected,

- delaying the pyrolysis and the combustion of combustible materials, - possibly, reducing the corrosion of the storage, transport and / or handling equipment of said compositions. Thus, in US Pat. No. 3,334,045, an aqueous composition for delaying pyrolysis and / or combustion has been proposed which can be used during air drops in order to establish fire barriers. Said composition contains a thickening agent capable of increasing the viscosity of water and which is a sodium bentonite clay pre-hydrated at a rate of 1 to 9% by weight (relative to water), and a retarding salt such monoammonium phosphate, diammonium phosphate and ammonium sulfate in an amount of 10 to 25% by weight relative to water.

The maximum viscosity of the composition should not hinder pumping thereof. It has also been proposed in US Patent 3,409,550 a retardant aqueous composition usable during air drops; said composition contains water, a water-miscible thickening agent, diammonium phosphate and ammonium sulfate dissolved, in proportions otherwise specified, in water; it is in the form of an aqueous gel whose pH is between 6.5 and 7.5 and whose viscosity is at least 1000 centipoise.

Various corrosion reducing agents may be present in the composition in question. If various thickening agents are mentioned, the use of carboxymethylcellulose for this purpose is recommended. On the other hand, a minimum content of about 120 g of ammonium salts per liter of solution is recommended (1 pound per gallon).

More recently, it has been proposed (cf. US 4,822,524) to incorporate into a retarding composition specially adapted for aerial application a minor amount (of the order of 0.008 to 0.1% by weight) of xanthan gum in order to improve it. long-term stability and adhesion characteristics to the surface of the vegetation. The composition in question also contains a retarding salt chosen from ammonium phosphate, ammonium polyphosphates and ammonium sulfate, a thickener based on guar gum and an aqueous liquid carrier. Taking into account the content of ammonium salts (phosphate and / or sulphate) in the concentrated compositions and the dilution rates recommended before use, the use of these compositions, the principle interest of which is not disputed, is translated in practice by difficulties, even by impossibilities, to reconcile a viscosity satisfying the need for pumpability, an optimal deposition yield on the vegetation, an effect of fireproofing of the vegetation without spilling excessive quantities of phosphates likely to harm to the environment thus treated. In parallel, many previous studies have focused on the inhibition of corrosion induced by this type of composition and have proposed various additives for this purpose (cf. US 3,223,649; US 3,275,566; US 3,338,829; US 3,350,305; US 3,364,149 and US 4,176,071) . Other previous work has attempted to modify the viscosity of retarding compositions by adding synthetic polymeric compounds (cf. US 4,101,485).

Despite the extensive research that has been carried out for many years in the field of compositions useful for preventing and / or fighting fire, the problem of the fight in question with the least possible amount of organic compounds and / or Foreign or exogenous minerals in the water have not, to the knowledge of the applicant, been formulated yet and it does not seem that solutions could have been previously proposed. The present invention relates to a composition useful for preventing and / or fighting fire, the effectiveness of which is sensitive even to very low solids contents (less than or equal to 6% by weight) in an aqueous vector.

As a result, it becomes possible to use twisting compositions in the ground control processes, without risking undue harm to the environment by dumping large quantities of chemical compounds into it, the effectively useful concentration of retarding agent being able to be very weak in the compositions according to the invention.

Taken in its first aspect, the subject of the invention is a concentrated composition, useful after dilution and dissolution or dispersion in an essentially aqueous medium, for preventing and / or fighting against fire, comprising a clay, where appropriate, a retarding agent, one or more corrosion inhibitor (s), an anticryptogamic agent and / or a dye, characterized in that a) it contains fibers of plant origin comprising a majority of natural cellulose fibers and b) the quantity of said fibers relative to the whole (fibers + clay) is between 10 and 90% (by weight).

An essential characteristic of the present invention resides in the presence of fibers of plant origin comprising a majority of natural cellulose fibers. The term “fibers of vegetable origin comprising a majority of natural cellulose fibers” means mixtures of fibers comprising at least 50% (by weight) of cellulose fibers, treated by physical disintegration processes, thermomechanical or chemical processes.

The precise nature of the cellulose fibers is not critical. Thus, the fibers in question may come from various sources, such as papermaking, including the recovery of old paper or newsprint and various plant species, in particular wood shavings of resinous or leafy species, and may occur in a more or less refined form, i.e. freed beforehand of all or part of the lignin which they contain in the raw state.

It is preferred to use fibers originating from leafy, delignified and weakly refined species capable of offering better swelling of the water.

If the average size of the fibers can vary within wide limits, it is preferable to use fibers of which less than 5% have a length greater than or equal to 3 mm, longer fibers having a tendency to form lumps and to get wet when they are found in an aqueous vector. In addition, the presence of a large proportion (greater than 50%) of fibers that are too short (less than 500 microns) leads to too rapid sedimentation of the diluted compositions, which does not seem desirable during their use.

According to an advantageous variant, fibers are used, at least 50% of which have a length between .200 and 1500 microns and which preferably have an L / D ratio greater than or equal to 10.

As examples of fibers which may be suitable for the preparation of the compositions according to the invention, mention may be made of the cellulose fibers marketed by the company CELLULOSE DU PIN under the name "FLUFFOSE HD", those marketed by the company SADLAT under the name "SADLAFLOC-S20" and those sold by the company CE-LLULOSE-FULSTOFF-FABRIK under the names "TECHNOCEL 200C" and "TECHNOCÇL 400C".

The compositions based on "pure" cellulose fibers sold by the company CELLULOSE-FULSTOFF-FABRIK under the names "TECHNOCEL 200C" or "TECHNOCEL 400C" are more particularly preferred.

The compositions according to the present invention also contain at least one clay.

Examples of clays which may be suitable for the preparation of said compositions include: clay, lamellar or phyllitic materials, such as montmorillonite, bentonite, kaolinite, illite and beidelite and clays, with sheets discontinuous or fibrous, such as attapulgite and sepiolite, and mixtures thereof, π is preferable for the clays used to be free from abrasive materials; it is desirable that their silica content is less than 0.5% by weight. It is advantageous to use clays known to have a high swelling rate in water and / or exhibit a thixotropic behavior with a flow threshold in the presence of water, such as attapulgite and sepiolite and, preferably, to the sepiolite. Another essential characteristic of the present invention resides in the precise quantity of the cellulose fibers present in relation to the whole (fibers + clay).

As indicated at the beginning of this specification, this quantity must be between 10 and 90% by weight. This amount is advantageously between 20 and 80% by weight.

The compositions according to the present invention may contain a retarding agent. These agents are compounds well known to those skilled in the art who may refer for more information about them to the work "The Chemistry & Uses of Fire Retardants" by JW Lyons (in particular, pp. 149- 156). Examples of such compounds include mono- and diammonic phosphates, ammonium polyphosphates, ammonium sulfate, borax, sulfamic acid and its derivatives such as ammonium sulfamate, and mixtures thereof .

If the precise quantity of retarding agent is not critical during the use of the compositions, it is advantageous that in the compositions in question this quantity is greater than or equal to 30% (by weight) relative to that of the fibers .

As indicated at the beginning of this specification, an advantage presented by the compositions according to the present invention, ready for use, resides in the fact that the content of retarding agent can then be less than or equal to 5% by weight; an amount greater than or equal to 0.5% by weight may be recommended. Preferably, this amount is between 0.5 and 2% (by weight).

The compositions according to the present invention can of course be in various forms being recalled here, for the sake of clarity, that at the time of their application to the prevention and / or fight against fire and in particular, against the fire of forest, they will be in the form of an aqueous dispersion, water representing the major part in this form of presentation ready for use.

The compositions in question, before their use, may be in the mass form of blocks of pasty consistency (such as that of a mastic), compacted briquettes, platelets or sheets, or in particulate form such as powders, flakes, granules, pellets, more or less hardened rods, for example by drying, or in the form of a more or less viscous gel, a dispersion or a concentrated solution, water representing the major part in these presentations and the dry extract representing only a minor part by weight, but essential for the proper functioning of the fire prevention and / or fire fighting process. An advantage of the compositions according to the invention which are in bulk or particulate form lies in the fact that they are easily dispersible or even disintegrable in an aqueous liquid carrier.

A particularly advantageous category of compositions according to the invention consists of those which contain:

- from 1 to 20% and, preferably, from 2 to 10% by weight (counted as dry extract, measured after drying at approximately 40 ° C.) of a composition whose dry extract has just been described and

- from 80 to 99% and, preferably, from 90 to 98% by weight of water. Such compositions (specialties or ready-to-use compositions) can be easily diluted, if necessary, in an aqueous vector; dilution can be done with great precision.

Preferably, the ready-to-use compositions have a viscosity measured with a Brookfield RTND viscometer (mobile body no. 3, speed of rotation: 10 revolutions / minute) of between 500 and 3000 mPa.s and, preferably, between 1500 and 2500 mPa.s.

Indeed, such compositions have the additional advantage of being pumpable, which makes their use all the more easy with pre-existing equipment.

Compositions according to the present invention in other forms mentioned above will be brought in the form of an aqueous dispersion, at the time of their application to the prevention and / or fight against fire and in particular, against forest fire, water then representing the major part in this ready-to-use form of presentation, the dry extract content then representing from 1 to 20 and, preferably from 2 to 10% by weight.

In a ready-to-use and particularly advantageous form, the compositions have a dry extract content of less than or equal to 6% by weight.

The compositions according to the present invention may of course contain minor amounts of other additives such as, one or more corrosion inhibitors, a dye, an anticryptogamic agent, as the case may be, a foaming agent or an anti-foaming agent. The total amount of these various additives will not normally exceed 1% by weight of the ready-to-use composition.

Of course, the presence of these various additives remains optional and their incorporation can be accomplished at various stages, either in the part constituting the dry extract, or in the water with which the dry extract or a concentrated composition will be diluted. Indeed, as the compositions in question contain few phosphates, they have, in the presence of water, a neutral or slightly basic pH, of the order of 7 to 8. Therefore, when they are brought into contact with ferrous metals, they do not cause visible corrosion of the latter. Furthermore, in the range of pH values indicated, the aluminum is stable even in the presence of strong electrolytes.

This constitutes an important practical advantage of the compositions according to the present invention.

Another advantage of the said compositions lies in the fact that they are compatible with the retarding compositions conventionally used in this application and with the wetting agents and the foaming agents which it may be desirable to use in certain cases.

Thus, the aqueous vector used to dilute the compositions according to the present invention before their use, can be substantially pure water, such as it is present on a distribution network or on an industrial site, or water containing a or several additives of varied nature ensuring, for example, at least one of the following traditional functions: limiting or preventing the development of microorganisms such as bacteria, fungi and yeasts, promoting or limiting the appearance of a foam, materialize the treated area by coloring it and, if necessary, inhibit corrosion of the metal parts in contact with the composition. If necessary, it is possible to use sea water, the compositions according to the invention being compatible with this aqueous medium.

The compositions in question can be prepared in a simple manner, for example by mixing the various components (clay, cellulose fibers, if necessary retardant and other additives) which are in the form of particles or brought to the state of almost dry powders (containing maximum 10% water).

Initially, the mixture of dry powders is swollen naturally due to the presence of the cellulose fibers which are relatively light and give the whole an apparent density of the order of 500 g / l.

In a second step, the mixture thus operated can either be compacted and, if necessary, bagged for example, or be granulated in a manner known per se, in the presence of water.

The compositions in question can also be prepared wet from a paper pulp containing on the order of 3 to 10% by weight of fibers.

In the context of this process, clay and, if necessary, the retarding agent are added to the pulp in the desired proportions. The whole is then filtered and the cake thus obtained is brought to the desired degree of dryness. As indicated at the beginning of this memo, the invention also relates to the application of the compositions which have just been described for the prevention and / or the fight against fire.

The application of said compositions to the prevention and / or the fight against dry fires is more particularly envisaged. The sites around which and / or on which it is particularly appropriate to project the ready-to-use compositions, in the sense specified above, may be areas of vegetation (forests, coppice, brush, scrubland, ... ), residential areas, industrial equipment such as warehouses, or mixed areas, comprising plants and / or cellulosic materials or of cellulose origin, likely to generate dry fires. Of course, the projection of the ready-to-use compositions around and / or on the sites in question will be carried out both from the ground and by air.

The following examples illustrate the present invention.

EXAMPLES

General mode of preparation of the compositions according to the invention.

In a Cellier delitor, water and clay are introduced. The whole is mixed at speed 2. Once the mixture has thickened, the desired amounts of fibers and retarding agent are added respectively.

The precise nature of the various ingredients, their proportion and the dry extract content (E.S.) of the composition are indicated in Tables (I) to (IV) below.

For some of these compositions, the water was removed followed by drying in an oven (40 ° C) of the residual material in order to determine the behavior of the latter once it has been diluted in water. The same results were obtained.

Test conditions for the various compositions diluted in water

- Determination of the initial deposit yield:

A rectangular poplar wood plate (10 cm x 3.5 cm x 0.2 cm) is brought to 35 ° C for 24 hours. It is weighed and then immersed in a vertical position for 30 seconds in the composition under consideration. After immersion, the plate is re-weighed. The deposit yield (RT) is defined by the following relationship: mass of the wafer after immersion _x QQ mass of the wafer before immersion

- Yield of deposit after drying

The procedure is similar, except that the second weighing is carried out after the immersed wafer has dried under otherwise specified conditions. The yield is then defined by a relationship similar to the previous one, in which the mass in numerator is that of the immersed wafer and then dried.

- Fire tests

The fire test is carried out on a batch of wafers treated as indicated above. On the one hand, a device is used to generate a pilot flame (of the CAMPING GAZ ^R / SOUDO-GAZ ^{R type} ) which is substantially planar and horizontal and, on the other hand, an epiradiator (power 500 watts, RC2 model sold by the company PROLABO) fitted with a circular grid support 11 cm in diameter.

A circular grid, made of steel and square mesh (W x L cm) is positioned 1 cm away from the focal point of the Epirator. The assembly (grid and grid support) is inclined 30 degrees from the horizontal. The whole is brought to a temperature of the order of 600 to 700 ° C., for approximately 30 minutes.

The pilot flame generator device (burner) is positioned so that the end of the burner is located 3 cm from the upper part of the plate which will later be positioned on the grate of the epiradiator.

The burner is then lit (temperature reached approx. 1650 ° C). Then, simultaneously, we place the plate on the grid and start the stopwatch. With the burner still in operation, note the time required for the first flames to appear on the wooden plate. This time, which is 15 to 16 seconds for an untreated wood chip, called the flammability time is designated by TI in the following.

If necessary, the mass of residues is then determined after the flames have disappeared.

- Stability of suspensions:

Suspensions with a total volume of 1 liter are prepared, the dry extract content, the nature of the ingredients and their proportions being indicated elsewhere. Closed test pieces are left to stand at room temperature. The volume of supernatant liquid in each of the test pieces is determined after a time t of rest.

This volume is expressed as a% of the total volume as well as the height of the sediment.

Examples 1 to 7 - Control tests (a) to ff)

7 compositions are prepared as indicated above from "pure" cellulose fibers sold by the company CELLULOSE-FULSTOFF-FABRIK under the name "TECHNOCEL 200C" and sepiolite clay (sold by the company OMYA SA under the name PANGEL HV) and where appropriate, various delaying agents.

The respective dry extract contents, the composition of each dry extract and the results obtained are shown in table (I) below. The following conventions are used:

E.S .: Dry extract DAP: Dammonium phosphate

K2HPO4: Di-potassium phosphate

Sθ4 (NH4) 2: Ammonium sulphate SUÇA: Calcium sulphamate

SUNH: Ammonium sulfamate PPA: Ammonium polyphosphate

The control test (a) gives the results of the fire tests of the untreated wood chip.

The control test (b) gives the results obtained on a wafer treated with water alone.

The control test (c) was carried out on a wafer treated with a composition not falling within the scope of the present invention comprising di-ammonium phosphate and tragacanth.

The control test (d) was carried out on a wafer treated with a composition not falling within the scope of the present invention comprising ammonium polyphosphate and attapulgite; composition sold by BIOGEMA under the name Fire Troll ^R 931.

The control test (e) was carried out on a wafer treated with a composition not falling within the scope of the present invention comprising only cellulose fibers in its dry extract.

The control test (f) was carried out on a wafer treated with a composition not falling within the scope of the present invention comprising only sepiolite in its dry extract. TABLE 1 = FIRE BEHAVIOR

ND = not determined

TABLE II = SEDIMENTATION

Examples 8 to 17

10 compositions are prepared as indicated above, except that the retarding agent which is di-ammonium phosphate, is introduced directly into the water, in an amount of 1% by weight of the total solution, before the tests with fire, and that the cellulose fibers and the clay used can be of various natures.

The "short" fibers are "TECHNOCEL 200C" fibers sold by the company CELLULOSE-FULSTOFF-FABRIK. The "long" fibers are "TECHNOCEL 400C" fibers sold by the company CELLULOSE-FULSTOFF-FABRIK.

The clay can be sepiolite (PANGEL HV sold by the company OMYA S.A.) or attapulgite (ATTAGEL 30 sold by the company ENGELHARDT).

The specific conditions, as well as the results obtained are shown in the table (read) below.

The viscosity is measured before addition of the retarding agent. The deposition yield is the subject of two determinations: one before drying (initial deposition yield) and the other after 1 h 30 of drying at 40 ° C.

TABLE III

(*) mobile 2

NB: The complement to 100% of the dry extract is obtained by the addition of DAP.

Example 18 - Control tests (A) to (D)

In these examples, the stability after 24 hours of various suspensions, free of retarding agent, is determined; the composition of these suspensions containing either sepiolite or cellulose fibers (Type: TECHNOCEL 200C) or a mixture of the two, as well as the results obtained are shown in Table IV below.

TABLE IV

The stability of the suspension (example 18) is clearly demonstrated.

Example 19 - Control tests (E) and (F)

In these examples, the evolution of the viscosity of the various suspensions, free of delaying agent, examining either attapulgite alone in variable concentration (control test E) or sepiolite alone in variable concentration (control test F) is examined. ), or a mixture of cellulose fibers (2% by weight,

TECHNOCEL 200 C) and sepiolite in variable concentration (example 19).

The viscosity profiles obtained in the three examples are shown in the attached single figure. In this figure are plotted on the abscissa the clay concentrations expressed in% by weight, a graduation representing 0.5% by weight.

The ordinates show the viscosity values expressed in centipoise, a graduation representing 500 centipoise. The clay concentrations explored are between 1 and 4% by weight; the viscosities measured range from a few tens of centipoises to around 5500 centipoises.

Curve 1 gives the profile obtained for attapulgite taken in isolation (control test E).

Curve 2 gives the profile obtained for sepiolite taken in isolation (control test F)

Curve 3 gives the profile obtained for the mixture of sepiolite and cellulose fibers (example 19).

Claims

1) A concentrated composition, useful after dilution and dissolution or dispersion in an essentially aqueous medium for the prevention and / or the fight against fire, comprising a clay, if necessary, a retarding agent, one or more inhibitor (s) of corrosion, an anticryptogamic agent and / or a dye, characterized in that: a) it contains fibers of vegetable origin comprising a majority of natural cellulose fibers and b) the quantity of said fibers relative to the whole (fibers + clay) is between 10 and 90% (by weight).

2) Composition according to claim 1, characterized in that the amount of fibers relative to the whole (fibers + clay) is between 20 and 80%

(in weight).

3) Composition according to claim 1 or 2, characterized in that the cellulose fibers are chosen from those originating from leafy, delignified and slightly refined species.

4) Composition according to any one of the preceding claims, characterized in that the cellulose fibers are chosen from those of which less than 5% have a length greater than or equal to 3 mm.

5) Composition according to any one of the preceding claims, characterized in that the cellulose fibers are chosen from those whose average length is between 200 and 1500 microns and which preferably have a L / D ratio greater than or equal to 10.

6) Composition according to any one of the preceding claims, characterized in that the clay is chosen from the group consisting of bentonite, attapulgite, sepiolite and their mixtures.

7) Composition according to any one of the preceding claims, characterized in that the clay used is sepiolite.

8) Composition according to any one of the preceding claims, characterized in that it contains a retarding agent, the amount of the agent retarding with respect to that of the fibers being greater than or equal to 30% (by weight).

9) An aqueous composition, ready to use in the prevention and / or fight against fire, characterized in that it contains:

- from 1 to 20% and, preferably, from 2 to 10% by weight (counted as dry extract, measured after drying at approximately 40 ° C) of a composition according to any one of the preceding claims and

- from 80 to 99% and preferably from 90 to 98% by weight of water.

10) A composition according to claim 9, characterized in that it has a viscosity measured with a Brookfield RTND viscometer (mobile body No. 3, speed of rotation: 10 revolutions / minute) between 500 and 3000 mPa.s (centipoises ) and preferably between 1,500 and 2,500 mPa.s (centipoises).

11) A composition according to claim 9 or 10, characterized in that its dry extract content is between 2 and 6% by weight.

12) A composition according to any one of claims 9 to 11, characterized in that its content of retarding agent is between 0.5 and 5% by weight.

13) A composition according to claim 12, characterized in that its content of retarding agent is between 0.5 and 2% (by weight).

14) A method of preventing and / or fighting against fire comprising the projection around and / or on a site, of an aqueous composition according to any one of claims 9 to 13.

15) Method according to claim 14, characterized in that the site comprises plants and / or materials capable of generating dry fires.

16) Method according to claim 14 or 15, characterized in that the projection is carried out from the ground.

17) Method according to claim 14 or 15, characterized in that the projection is carried out by air.