EP2753403B1 - Siloxane-containing fire extinguishing foam - Google Patents

Description

The present invention relates to the field of fire-extinguishing foams.

Especially in fires of larger amounts of liquid organic chemicals such. Fuels are the extinguishing water usually added special foaming agents. These have surface-active properties and, in contrast to conventional extinguishing foams, permit the self-wetting of the surface of the burned material. Therefore, such a so-called AFFF (Aqueous Film Forming Foams) extinguishing foams form as a special feature a film of water on the surface of the burning liquid. The resulting vapor barrier makes it more difficult for the combustible liquid to pass into the gas phase and thus maintain the fire or form ignitable or explosive gas mixtures. The wetting ability characteristic of the AFFF foams also allows the foam to slide on the surface of the burning liquid so as to reach areas where the foam can not be applied directly. In addition, the foam surface closes after failure (for example, by falling objects) again independently. Furthermore, the film also flows and acts in areas that are not directly reached by foam.

For a long time, perfluorooctylsulfonate (PFOS) has been the drug of choice in such fire-fighting foams. However, as it was recognized to be toxic, persistent and bioaccumulating, its use was strengthened by EU Directive 2006/122 / EC of 12.12.2006 limited. Extinguishing foams with more than 50 ppm PFOS content must not be used in the EU. Today, various other polyfluorinated surfactants are used as substitutes for PFOS in AFFF. These surfactants are heretofore believed to be non-bioactive or at least less bioaccumulating and toxic. However, a final assessment is still pending and the fundamental problem of persistence of polyfluorinated compounds remains intact.

It is therefore the task of finding alternative high-performance AFFF fire-extinguishing foam concentrates which contain the most equally effective but preferably less toxic and preferably halogen-free surfactants.

This object is solved by claim 1 of the present invention. Accordingly, a fire-extinguishing foam concentrate is proposed, which comprises a surfactant according to claim 1, containing at least one substituted or unsubstituted carbohydrate or carbohydrate derivative and at least one oligosiloxane. The term "containing" in this context means that both the carbohydrate or carbohydrate derivative and the oligosiloxane are subcomponents of a larger molecule and both are linked via covalent bonds to the remainder of the molecule.

• Durch die hohe Wasserlöslichkeit der Kohlenhydrate ist die Gesamtmolekülgröße der erfindungsgemäßen Tenside bei ausreichender Löslichkeit hinreichend klein; kleine Moleküle sind bei den meisten Anwendungen bevorzugt, da ihre Diffusionskoeffizienten höher sind.

Surprisingly, it has been found that the surfactants according to claim 1 are suitable for producing water-film-forming fire-extinguishing foams and, depending on the application, at least one of the following advantages can be achieved:

• Due to the high water solubility of the carbohydrates, the total molecular size of the surfactants of the invention is sufficiently small with sufficient solubility; Small molecules are preferred in most applications because their diffusion coefficients are higher.

• Die Tenside sind halogen-, insbesondere fluorfrei und lassen sich weitestgehend aus nachwachsenden Rohstoffen herstellen.
• Die Tenside ermöglichen die selbständige Bildung eines geschlossenen Wasserfilms auf der Oberfläche des Brandguts (z.B. Treibstoff): Als Dampfsperre behindert dieser Wasserfilm den Übergang der brennbaren Flüssigkeit in die Gasphase und minimiert auf diese Weise, dass das Brandgut das Feuer unterhält oder brand-/explosionsfähige Gasgemische bildet.
• Aufgrund der Wasserfilmbildung ist es besonders für Flüssigkeitsbrände geeignet, ohne poly- oder perfluorierte Verbindungen zu enthalten

Tensides are among others from the SU19681282743 , of the US 2007/134283 and US 2007/135329 known.

• The surfactants are halogen-free, in particular fluorine-free and can be produced as far as possible from renewable raw materials.
• The surfactants enable the self-formation of a closed water film on the surface of the fire (eg fuel): As a vapor barrier, this water film impedes the transition of the flammable liquid into the gas phase and thus minimizes the fire that sustains the fire or flammable gas mixtures forms.
• Due to the formation of water film, it is particularly suitable for liquid fires, without containing poly- or perfluorinated compounds

oder Mischungen daraus,

• wobei A ein substituiertes oder unsubstituiertes Kohlenhydrat oder Kohlenhydratderivat mit ein bis vier Zuckereinheiten ist,
• B eine optionale Linkersubstruktur aus mindestens einem Atom oder eine Kette darstellt sowie C ein Oligosiloxan ist, bevorzugt ein Di-, Tri- oder Tetrasiloxan

Im Folgenden werden die Unterbestandteile des Tensids näher erläutert, wobei einzelne Merkmale oder Angaben beliebig kombiniert werden können.According to the invention, the surfactant comprises a molecule selected from the group comprising

or mixtures thereof,

• wherein A is a substituted or unsubstituted carbohydrate or carbohydrate derivative having one to four sugar units,
• B is an optional linker substructure of at least one atom or chain and C is an oligosiloxane, preferably a di-, tri- or tetrasiloxane

In the following, the subcomponents of the surfactant are explained in more detail, wherein individual features or information can be combined as desired.

Subcomponent A:

A is a substituted or unsubstituted carbohydrate or carbohydrate derivative having one to four sugar units. Preferred are mono-, di- and trisaccharides, i. one, two or three sugar units.

Further, subcomponent A or parts of subcomponent A may also be derived from carbohydrate derivatives such as e.g. the sugar acids (aldonic acids, uronic acids or aldaric acids), sugar alcohols (alditols), aminosugars or cyclitols, and their ethers, esters, amides or thioesters.

The term "sugar moieties" or "carbohydrate" is understood to mean, in particular, hexoses, pentoses or cyclitols, which (in the presence of di- or higher saccharides) are preferably linked to one another in a glycosidic manner.

As described, the carbohydrates may be substituted or unsubstituted, with unsubstituted carbohydrates being preferred because of the resulting higher water solubility.

If the carbohydrates are substituted, ethyleneoxy, oligo (ethyleneoxy), methyl, ethyl, allyl or acetyl substituents are preferred.

Preferred carbohydrates or carbohydrate derivatives in the context of the present invention are
for monosaccharides: glucose, glucosamine, fructose, galactose
for disaccharides: maltose, isomaltose, sucrose, cellobiose, lactose, trehalose
for trisaccharides: raffinose, maltotriose, isomaltotriose, maltotriulose, ciceritol
for cyclitols: inositol, quebrachitol, pinitol
in the case of sugar acids: gluconic acid, glucuronic acid, glucaric acid, tartaric acid, galactonic acid, galacturonic acid, maleic acid, mannuronic acid, mannaric acid, fructonic acid, fructuronic acid, fructaric acid, arabinonic acid, arabinuronic acid, arabinaric acid, xylonic acid, xyluronic acid, xylaric acid, ribonic acid, riburonic acid, ribaric acid, ascorbic acid
for alditols: sorbitol, xylitol, mannitol, lactitol, maltitol, isomaltitol, threitol, erythritol

Subcomponent B:

B is an optional linker substructure of at least one atom or chain, preferably of carbon and / or nitrogen and / or oxygen atoms (O-O bonds being excluded).

This chain may be a pure alkyl chain, i. B is an unsubstituted or optionally alkyl-substituted alkylene radical.

Alternatively, B may also contain ether, ester or amide groups. For example, B may contain glycerol, poly- or oligoethylene glycol, poly- or oligopropylene glycol, pentaerythritol, alkylamines or carboxylic acids as a substructure.

B is preferably linked to residue A glycosidically via an anomeric carbon atom. In the case of a carboxylic acid derivative as A, B may also be linked to A via an amide or ester bond.

With residue C (the siloxane), B is preferably linked via an Si-C or Si-O bond.

It should be noted that with some surfactants according to the present invention, subcomponent B may also be omitted, i. if necessary, A and C are directly linked.

Furthermore, with some surfactants according to the present invention, the radical B-C or C may also be attached to other regiochemical positions of the carbohydrate or carbohydrate derivative A.

Subcomponent C:

C is an oligosiloxane, preferably a di-, tri- or tetrasiloxane. The methyl and ethyl siloxanes or mixed siloxanes with methyl and ethyl radicals are preferred.

If C is a tri- or higher siloxane, C may be linked to B (or optionally A) via one of the terminal siloxanes (forming a kind of "continuous chain"), alternatively C may be combined with B (or optionally A ) may also be linked via one of the medium siloxanes, so that a type of X- or T-shaped or branched structure forms.
If C is derived from a di- or trihydrosiloxane, the substructures AB or A joined to C may be the same or different.

wobei jedes R, unabhängig voneinander, für Ethyl oder Methyl steht und n zwischen 0 und 10 liegt, bevorzugt zwischen 0 und 5, noch bevorzugt 0, 1 oder 2 ist.Preferably, C has one of the following structures:

wherein each R, independently of one another, is ethyl or methyl and n is between 0 and 10, preferably between 0 and 5, more preferably 0, 1 or 2.

According to a preferred embodiment of the present invention, the fire-fighting foam concentrate also comprises one or more of the following constituents: foaming agents, film formers, film stabilizers, antifreeze preservatives and corrosion inhibitors, solubilizers and buffers.

In the following, these components are explained in more detail, with individual features or specifications can be combined as desired.

foaming agents:

To improve the foaming cosurfactants can be added. In particular, these may be: linear alkylbenzenesulfonates, secondary alkanesulfonates, sodium alkylsulfonates, α-olefmsulfonates, sulfosuccinic acid esters, α-methyl ester sulfonates, alcohol ethoxylates, alkylphenol ethoxylates, fatty alcohol ethylene oxide / propylene oxide adducts, Glycoside surfactants (eg, glucopone, this is particularly preferred), lauryl sulfates, laureth sulfates, imidazolium salts, lauriminodipropionate, acrylic copolymers.
Suitable counterions for the anionic surfactants present in this list are, in particular, Li ⁺ , Na ⁺ , K ⁺ , NH ₄ ⁺ , N (C ₂ H ₅ ) ₄ ⁺

Film Formers, Film Stabilizers:

To improve the film and foam properties, the foaming agent concentrate may, inter alia, be admixed with the following constituents: polysaccharides, alginates, xanthan gum, starch derivatives

Antifreeze:

To improve the frost resistance and the low temperature applicability, the foaming agent concentrate may be admixed with, inter alia, the following components: ethylene glycol, propylene glycol, glycerol, 1-propanol, 2-propanol, urea, inorganic salts

Preservatives and corrosion inhibitors:

In order to improve the storage stability and to protect the storage vessels and apparatus, the foam concentrate may be admixed inter alia with the following components:
Formaldehyde solution, alkylcarboxylic acid salts, ascorbic acid, salicylic acid, tolyltriazoles

Solubilizers:

To improve the solubility of the constituents, the foam concentrate may be admixed with, inter alia, the following constituents:
Butyl glycol, butyl diglycol, hexylene glycol

Buffer:

• Kaliumdihydrogenorthophosphat/N atriumhydroxid,
• Tris(hydroxymethyl)aminomethan/Salzsäure,
• Dinatriumhydrogenphosphat/SalzsäureZitronensäure/Natriumhydroxid, Zitronensäure/Natriumacetat.

The siloxane surfactants are pH-sensitive in terms of shelf life. A buffering of the concentrate to a pH of about 7 is therefore advantageous. Buffer systems can be for example:

• Potassium dihydrogen orthophosphate / sodium hydroxide,
• Tris (hydroxymethyl) aminomethane / hydrochloric acid,
• Disodium hydrogen phosphate / hydrochloric acid citric acid / sodium hydroxide, citric acid / sodium acetate.

The present invention also relates to the use of a surfactant containing at least one substituted or unsubstituted carbohydrate or carbohydrate derivative and at least one oligosiloxane as an additive to fire-fighting foams and / or concentrates.

The above-mentioned and the claimed components to be used according to the invention described in the exemplary embodiments are not subject to special conditions of size, shape, material selection and technical design, so that the selection criteria known in the field of application can be used without restriction.

Further details, features and advantages of the subject matter of the invention will become apparent from the subclaims and from the following description of the accompanying examples, which are purely illustrative and not restrictive.

EXAMPLE I:

Example I relates to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of 2 g / Lg / L Example I was investigated; it was found out that this connection is spreading.

The same behavior was demonstrated by a solution of 2 g / L Example I and 0.5 g / L SDS.

EXAMPLE II

Example II relates to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of 2 g / L Example II and 0.24 g / L SDS was investigated; it was found that this compound spreads very fast. A similar behavior (although not quite as fast spreading) was for a solution of 2 g / L Example II and 0.25 g / L Hansanol NS 242 conc. (Sodium laureth sulfate 2EO) found. A solution of 500 mg / L Example II and 6 g / L Glucopon 215 CS UP (alkyl polyglycoside with C8-C10 alkyl chain length) was also investigated and found to be spreading.

EXAMPLE III:

Example III relates to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of 2 g / L Example III and 0.5 g / L SDS was investigated; it was found that this compound spreads very fast.

EXAMPLE IV:

Example IV relates to a surfactant according to the present invention having the following structure

The spreading behavior of a solution of 2 g / L Example IV was investigated; it was found that this compound spreads very fast.

The same behavior was demonstrated by a solution of 2g / L Example IV and 0.5g / L SDS.

EXAMPLE V:

Example V relates to a surfactant according to the present invention having the following structure

The spreading behavior of a solution of 2 g / L Example V and 0.5 g / L SDS was investigated; it was found that this compound spreads very fast.

EXAMPLE VI:

Example VI refers to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of 2 g / L Example VI and 0.5 g / L SDS was investigated; it was found that this compound spreads very fast.

EXAMPLE VII:

Example VII relates to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of about 250 mg / L Example VII was investigated; it was found that this compound spreads very fast. The same applies to a solution of 500 mg / L Example VII and 6 g / L Glucopon 215 CS UP (alkyl polyglycoside with C8-C10 alkyl chain length).

EXAMPLE VIII:

Example VIII relates to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of 2 g / L Example VIII and 0.5 g / L SDS was investigated; it was found out that this connection is spreading.

The same behavior was demonstrated by a solution of 2 g / L Example VIII and 6 g / L Glucopon 215 CS UP (alkyl polyglycoside with C 8 -C 10 alkyl chain length).

EXAMPLE IX:

Example IX relates to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of 2 g / L Example IX and 0.5 g / L SDS was investigated; it was found out that this connection is spreading.

The same behavior was shown by a solution of 2 g / L Example IX and 6 g / L Glucopon 215 CS UP (alkyl polyglycoside with C 8 -C 10 alkyl chain length).

EXAMPLE X:

Example X refers to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of 2 g / L Example X was investigated; it was found out that this connection is spreading. Similarly, for a solution of 2 g / L, Example X and 0.5 g / L SDS apply.

The same behavior was demonstrated by a solution of 2 g / L Example X and 6 g / L Glucopon 215 CS UP (alkyl polyglycoside with C 8 -C 10 alkyl chain length).

EXAMPLE XI:

Example XI refers to a surfactant according to the present invention having the structure:

The spreading behavior of a solution of 2 g / L Example XI and 0.5 g / L SDS was investigated; it was found out that this connection is spreading.

The same behavior was shown by a solution of 2 g / L Example XI and 6 g / L Glucopon 215 CS UP (alkyl polyglycoside with C8-C10 alkyl chain length).

Comparative Examples:

As comparative examples, surfactants were selected which contain polyethylene glycol units instead of the carbohydrate residues.

COMPARATIVE EXAMPLE I

As comparison surfactant I, a surfactant was selected which contains polyethylene glycol units instead of the carbohydrate residues. It has the following structure:

A solution of 2 g / L Comparative Example I and 0.5 g / L SDS was investigated. The solution collects at the bottom of the dish, no spreading was observed. The same behavior was shown by a solution of Comparative Example I without SDS.

COMPARATIVE EXAMPLE II

As Comparative Example II, a compound having the following structure was chosen:

A solution of 2 g / L Comparative Example II and 0.5 g / L SDS was investigated. The solution collects at the bottom of the dish, no spreading was observed. The same behavior was shown by a solution of Comparative Example II without SDS.

COMPARATIVE EXAMPLE III

As Comparative Example III, a compound having the following structure was chosen:

A solution of 2 g / L Comparative Example III and 0.5 g / L SDS was investigated. The solution collects at the bottom of the dish, no spreading was observed. The same behavior was exhibited by a solution of Comparative Example III without SDS.

COMPARATIVE EXAMPLE IV

As Comparative Example IV, a compound having the following structure was chosen:

A solution of 2 g / L Comparative Example IV and 0.5 g / L SDS was investigated. The solution collects at the bottom of the dish, no spreading was observed. The same behavior was exhibited by a solution of Comparative Example IV without SDS.

Preparation of Glycoside Siloxanes

bzw.

The siloxane glycoside surfactants shown in the examples can be prepared, inter alia, from the carbohydrates as follows:

respectively.

Investigation of spreading behavior

To study the spreading behavior, 5 ml of cyclohexane were placed in a 9 cm diameter Petri dish. One drop each of the unfoamed surfactant solution was then added and observed as to whether and how the surfactant solution spreads on the surface of the cyclohexane.

The individual combinations of the components and the features of the already mentioned embodiments are exemplary; the exchange and substitution of these teachings with other teachings contained in this document with the references cited are also expressly contemplated. Those skilled in the art will recognize that variations, modifications and other implementations described herein may also occur without departing from the spirit and scope of the invention. Accordingly, the above description is illustrative and not restrictive. The word used in the claims does not exclude others Components or steps. The indefinite article "a" does not exclude the meaning of a plural. The mere fact that certain measures are recited in mutually different claims does not make it clear that a combination of these dimensions can not be used to advantage. The scope of the invention is defined in the following claims and the associated equivalents.

Claims (4)

1. Fire extinguishing foam concentrate comprising a surfactant which includes at least one substituted or unsubstituted carbohydrate or carbohydrate derivative and at least one oligosiloxane, wherein the surfactant comprises a molecule selected from the group including

   

   

   or mixtures thereof, wherein

   A is a substituted or unsubstituted carbohydrate or carbohydrate derivative comprising one to four sugar units,

   B represents an optional linker substructure of at least one atom or a chain, and

   C is an oligosiloxane.
2. Concentrate according to claim 1, wherein C is a di-, tri- or tetra-siloxane.
3. Concentrate according to claim 1 or 2, wherein A represents a mono-, di- and trisaccharide, a sugar acid, an amino sugar or a cyclitol, or an ether, ester, amide or thioester of these compounds.
4. Use of a surfactant including at least one substituted or unsubstituted carbohydrate or carbohydrate derivative and at least one oligosiloxane as an additive to fire extinguishing foams and/or concentrates, wherein the surfactant comprises a molecule selected from the group including

   

   

   or mixtures thereof, wherein

   A is a substituted or unsubstituted carbohydrate or carbohydrate derivative comprising one to four sugar units,

   B represents an optional linker substructure of at least one atom or a chain, and

   C is an oligosiloxane.