EP1888185B1 - Use of aqueous dispersions of water-soluble and/or water-swellable polymers in extinguishing agents and method for fighting fires - Google Patents

Abstract

Use of aqueous dispersions of water-soluble and/or water-swellable anionic polymers and water-soluble neutralizing agents as an additive to aqueous extinguishing agents, and method for fighting fires with aqueous extinguishing agents, an aqueous dispersion of water-soluble and/or water-swellable anionic polymers and at least one water-soluble neutralizing agent being mixed with water so that the mixture has a polymer content of not more than 5% by weight and a pH of at least 5.5.

Description

The invention relates to the use of aqueous dispersions of water-soluble and / or water-swellable polymers in extinguishing agents and a method for combating fires with aqueous extinguishing agents which contain at least one polymer.

From the US-A 3,229,769 It is known that, for example, it is possible to stem or prevent the spread of fire in forests by coating the areas of flammable materials adjacent to a fire with a finely divided coating composition which contains, as an essential constituent, crosslinked, water-swollen polymers. The polymers have a high water absorption capacity, eg up to 1040 g of water per g of polymer. They are contained in an amount of 0.01 to 5 wt .-% in the extinguishing agent. Examples of suitable polymers are crosslinked polyacrylamides or alkali metal or ammonium salts of crosslinked polyacrylic acids.

From the US-A 3,976,580 It is known to use an aqueous gel of polyacrylamide and bentonite to combat fire. The mixture can be stored, for example in the form of a dry powder and dosed when used as a fire extinguishing agent in a stream of water, for example, in a fire hose and used together with the extinguishing water for fire fighting.

From the EP-A 649 669 An extinguishing agent is known that is applicable both as a dry extinguishing agent and as an extinguishing agent additive in water. The extinguishing agent consists essentially of powdery, hydrogel-forming polymers and at least one material with a high surface area and / or capillary and / or fibrous structure. The extinguishing agents may optionally contain an adhesive to improve the adhesion of the hydrogels to the source of the fire.

Other methods and apparatus for fire fighting using superabsorbent polymers and water are known from the US-A 5,849,210 and the US Pat. No. 6,786,286 known.

When using hydrogels, in particular superabsorbent polymers (SAP) for firefighting, there is a risk that the hydrogels will agglomerate and thus lead to a disturbance in the firefighting. In extreme cases, even the functioning of the fire-fighting device is no longer given be. Furthermore, the handling of the systems is limited. By using small amounts of hydrogel there is a strong increase in viscosity, which is no longer manageable. Making the mixture of swollen SAP is also difficult.

The invention has for its object to provide for the control of fires that can be extinguished with water, a means available that increases the viscosity of water and / or slows the evaporation of water, but practically does not lead to lump formation, storage stable and easy to handle.

The object is achieved according to the invention with the use of aqueous dispersions of water-soluble and / or water-swellable anionic polymers and water-soluble neutralizing agents as an additive to aqueous extinguishing agents.

An aqueous extinguishing agent should primarily be understood to mean water which may optionally additionally contain at least one flame retardant, a dye and / or a wetting agent. Suitable flame retardants are, for example, ammonium polyphosphate, polybrominated biphenyls (PBB), polybrominated diphenyl ethers (PBDE), tetrabromobisphenol A (TBBA), chloroparaffins and antimony trioxide, alkali metal silicates and borates, urea mixtures, dicyandiamide and organic phosphates. Suitable wetting agents are all surface-active substances such as ethoxylated alcohols having at least 12 carbon atoms in the molecule, ethoxylated phenols and / or ethoxylated polyols such as glycerol or polyethylene glycols.

The preparation of the extinguishing agent can be carried out batchwise by a batch process or continuously. For example, an aqueous dispersion of a water-soluble and / or water-swellable anionic polymer is diluted with water to a polymer concentration of at most 5% by weight and the resulting aqueous solution is adjusted to a pH of at least 5.5 by adding at least one water-soluble neutralizing agent one. The aqueous polymer dispersion is preferably diluted by simultaneously introducing it into the water separately from the addition site of the polymer dispersion with the neutralizing agent and stirring the resulting mixture. However, the neutralizing agent can also be initially charged in the water used for dilution or dosed after addition of the polymer dispersion. However, it is possible, for example, to dilute the polymer dispersion continuously with water in a mixing chamber or in a multi-fluid nozzle under the action of a shear field and at the same time add at least one water-soluble neutralizing agent. The pH of the aqueous extinguishing agent is preferably in the range of 6 to 13, especially 7 to 12.

The polymer concentration of the aqueous extinguishing agent is usually 0.01 to 2.5 wt .-%. It is preferably in the range of 0.1 to 2.0 wt%. This extinguishing agent For example, have a viscosity of at least 1000 mPas up to 100,000 mPas, usually the viscosity of the extinguishing agent is above 3,000 mPas, preferably above 5,000 mPas and in particular above 10,000 mPas. The viscosity data refer to the measurement with a Brookfield R / S Rheometer, spindle V40203T01, at 20 rpm and a temperature of 23 ° C.

For example, the aqueous extinguishing agents to be used according to the invention have the advantage over extinguishing agents containing a superabsorber that they can be left for a longer time, even at relatively high temperatures, e.g. 80 ° C - can be stored without a practically measurable viscosity reduction. The extinguishing agents according to the invention are pumpable. They can therefore be used e.g. pumped from a reservoir near a fire and sprayed onto the material to be erased. Another application is to spray the extinguishing agent of the invention from a pressure vessel, which is under a nitrogen pressure of, for example, 10 bar, via a valve on burning material to extinguish the fire.

The invention furthermore relates to a method for combating fires with aqueous extinguishing agents which comprise at least one polymer, wherein an aqueous dispersion of water-soluble and / or water-swellable anionic polymers and at least one water-soluble neutralizing agent are each continuously mixed with water in such a way that the Mixture has a polymer content of at most 5 wt .-% and a pH of at least 5.5 and uses them directly for fire fighting.

The method for controlling fires with aqueous extinguishing agents which comprise at least one polymer can also be carried out batchwise by using an aqueous mixture for firefighting, obtainable by batch mixing an aqueous dispersion of water-soluble and / or water-swellable anionic polymers and at least one water-soluble neutralizing agent with water, wherein the polymer content of the mixture is at most 5, preferably at most 2.5 wt .-% and the pH is at least 5.5, preferably at least 7.5.

Aqueous dispersions of water-soluble and / or water-swellable anionic polymers are known, cf. for example US-A 4,380,600 ; EP-A 183 466 ; US-A 5,605,970 ; WO 97/34933 and DE-A 103 38 828 , Such dispersions are obtainable, for example, by polymerizing water-soluble anionic monomers from the group of the ethylenically unsaturated C ₃ -C ₅ -carboxylic acids, vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, vinylsulfonic acid and / or their alkali metal or ammonium salts in an aqueous solution which contains at least one other polymer and optionally at least one neutral salt as a stabilizer for the resulting polymer dispersion.

Preference is given to aqueous dispersions of water-soluble and / or water-swellable anionic polymers which are obtainable by polymerizing water-soluble anionic monomers in an aqueous solution which is free from neutral salts and as stabilizer at least one other water-soluble polymer from the group of polyethylene glycols, polypropylene glycols, Polyvinyl acetates, polyvinyl alcohols, polyvinylimidazoles, water-soluble starches, thermally, oxidatively or enzymatically degraded starches, cationically or anionically modified starches, maltodextrin and polydiallyldimethylammonium chloride.

1. (a) Pfropfpolymerisate von Vinylacetat und/oder Vinylpropionat auf Polyethylenglykolen, ein- oder beidseitig mit Alkyl-, Carboxyl- oder Aminogruppen endgruppenverschlossene Polyethylenglykole, Copolymerisate aus Alkylpolyalkylenglykolacrylaten oder Alkylpolyalkylenglykolmethacrylaten und Acrylsäure und/oder Methacrylsäure, Polyalkylenglykole mit Molmassen M_N von 1000 bis 100 000, ein- oder beidseitig mit Alkyl-, Carböxyl- oder Aminogruppen endgruppenverschlossene Polyalkylenglykole mit Molmassen M_N von 1000 bis 100 000
   und
2. (b) hydrolysierte Copolymerisate aus Vinylalkylethern und Maleinsäureanhydrid in Form der freien Carboxylgruppen und in Form der zumindest partiell mit Alkalimetallhydroxiden oder Ammoniumbasen neutralisierten Salze und/oder einer wasserlöslichen Stärke aus der Gruppe kationisch modifizierter Kartoffelstärke, anionisch modifizierter Kartoffelstärke, abgebauter Kartoffelstärke und Maltodextrin

enthält.In particular, come from the DE-A 103 38 828 known aqueous dispersions of water-soluble and / or water-swellable anionic polymers which are obtainable by polymerizing water-soluble anionic monomers in an aqueous solution which is free from neutral salts and as stabilizer at least one water-soluble polymer from the groups

1. (A) graft polymers of vinyl acetate and / or vinyl propionate on polyethylene glycols, on one or both sides with alkyl, carboxyl or amino groups endgruppenverschlossene polyethylene glycols, copolymers of Alkylpolyalkylenglykolacrylaten or Alkylpolyalkylenglykolmethacrylaten and acrylic acid and / or methacrylic acid, polyalkylene glycols having molecular weights M _N from 1000 to 100,000 , on one or both sides with alkyl, carboxyl or amino groups endgruppenverschlossene polyalkylene glycols having molecular weights M _N of 1000 to 100,000
   and
2. (B) hydrolyzed copolymers of vinyl alkyl ethers and maleic anhydride in the form of the free carboxyl groups and in the form of at least partially neutralized with alkali metal or ammonium bases salts and / or a water-soluble starch from the group of cationically modified potato starch, anionically modified potato starch, degraded potato starch and maltodextrin

contains.

1. (a) Pfropfpolymerisate von Vinylacetat und/oder Vinylpropionat auf (i) Polyethylenglykolen oder (ii) ein- oder beidseitig mit Alkyl-, Carboxyl- oder Aminogruppen endgruppenverschlossenen Polyethylenglykolen oder Polypropylenglykolen, Polyalkylenglykole, ein- oder beidseitig mit Alkyl-, Carboxyl- oder Aminogruppen endgruppenverschlossene Polyalkylenglykole
   und
2. (b) wasserlösliche Copolymere aus
   • (b1) nichtionischen monoethylenisch ungesättigten Monomeren,
   • (b2) kationischen monoethylenisch ungesättigten Monomeren und gegebenenfalls
   • (b3) anionischen monoethylenisch ungesättigten Monomeren, wobei der Anteil der einpolymerisierten kationischen Monomeren größer ist als der der anionischen Monomeren

enthält.In addition, such aqueous dispersions of water-soluble and / or water-swellable anionic polymers are preferably used according to the invention, which are obtainable by polymerizing water-soluble anionic monomers in an aqueous solution which is free of neutral salts and as stabilizer at least one water-soluble polymer from the groups

1. (A) graft polymers of vinyl acetate and / or vinyl propionate on (i) polyethylene glycols or (ii) on one or both sides with alkyl, carboxyl or amino groups endgruppenverschlossenen polyethylene glycols or polypropylene glycols, polyalkylene glycols, on one or both sides with alkyl, carboxyl or amino groups end-capped polyalkylene glycols
   and
2. (b) water-soluble copolymers
   • (b1) nonionic monoethylenically unsaturated monomers,
   • (b2) cationic monoethylenically unsaturated monomers and optionally
   • (b3) anionic monoethylenically unsaturated monomers, wherein the proportion of copolymerized cationic monomers is greater than that of the anionic monomers

contains.

1. (a) Pfropfpolymerisate von Vinylacetat und/oder Vinylpropionat auf (i) Polyethylenglykolen oder (ii) ein- oder beidseitig mit Alkyl-, Carboxyl- oder Aminogruppen endgruppenverschlossenen Polyethylenglykolen oder Polypropylenglykolen, Poly-alkylenglykole, ein- oder beidseitig mit Alkyl-, Carboxyl- oder Aminogruppen endgruppenverschlossene Polyalkylenglykole
   und
2. (b)
   1. (i) Homo- und Copolymerisate aus anionischen Monomeren,
   2. (ii) Copolymerisate aus anionischen und kationischen und gegebenenfalls neutralen Monomeren, wobei der Anteil der einpolymerisierten anionischen Monomeren größer ist als der der kationischen Monomeren und
   3. (iii) Copolymerisate aus mindestens einem anionischen Monomer und mindestens einem Monomer aus der Gruppe der Ester von anionischen Monomeren mit einwertigen Alkoholen, Styrol, N-Vinylpryrrolidon, N-Vinylcaprolactam, N-Vinylimidazol, N-Vinylformamid, Acrylamid, Methacrylamid, Vinylacetat und Vinylpropionat

enthält.The aqueous dispersions of water-soluble and / or water-swellable anionic polymers which are preferably used also include dispersions which are obtained by polymerizing water-soluble anionic monomers in an aqueous solution which is free of neutral salts and as stabilizer at least one water-soluble polymer from the groups

1. (a) graft polymers of vinyl acetate and / or vinyl propionate on (i) polyethylene glycols or (ii) polyethylene glycols or polypropylene glycols terminated on one or both sides with alkyl, carboxyl or amino groups, polyalkylene glycols, on one or both sides with alkyl, carboxyl or amino groups end-capped polyalkylene glycols
   and
2. (B)
   1. (i) homopolymers and copolymers of anionic monomers,
   2. (Ii) copolymers of anionic and cationic and optionally neutral monomers, wherein the proportion of copolymerized anionic monomers is greater than that of the cationic monomers and
   3. (Iii) copolymers of at least one anionic monomer and at least one monomer from the group of esters of anionic monomers with monohydric alcohols, styrene, N-vinylpryrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinylformamide, acrylamide, methacrylamide, vinyl acetate and vinyl propionate

contains.

Examples of ethylenically unsaturated, anionic monomers include monoethylenically unsaturated C ₃ -C ₅ -carboxylic acids, such as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleic acid, fumaric acid, vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, vinylphosphonic acid, itaconic acid and / or the alkali metal or ammonium salts of these acids into consideration. Preferred anionic monomers include acrylic acid, methacrylic acid, maleic acid and acrylamido-2-methylpropanesulfonic acid. Particularly preferred are aqueous dispersions of polymers based on acrylic acid. The anionic monomers can be polymerized either alone to form homopolymers or else mixed with one another to give copolymers. Examples of these are the homopolymers of acrylic acid or copolymers of acrylic acid with methacrylic acid and / or maleic acid.

However, the polymerization of the anionic monomers can also be carried out in the presence of other ethylenically unsaturated monomers. These monomers may be nonionic or may carry a cationic charge. Examples of such comonomers are acrylamide, methacrylamide; Acrylic acid esters of monohydric alcohols having 1 to 20 carbon atoms, methacrylic acid esters of monohydric alcohols having 1 to 20 carbon atoms, vinyl acetate, vinyl propionate, dialkylaminoethyl (meth) acrylates, dialkylaminopropyl (meth) acrylates, diallyldimethylammonium chloride, N-vinylformamide, vinylimidazole and quaternized vinylimidazole , Basic monomers such as dialkylaminoalkyl (meth) acrylates, for example dimethylaminoethyl acrylate or dimethylaminoethyl methacrylate, can be used in the polymerization both in the form of the free bases and in partially or completely neutralized form or quaternized in, for example, C ₁ - to C ₁₈ -alkyl halides. The comonomers are used in the preparation of the anionic polymers, for example in amounts such that the resulting polymers are water-soluble and have an anionic charge. Based on the total amount of monomers used in the polymerization the amount of nonionic and / or cationic comonomers, for example 0 to 99, preferably 5 to 75 wt .-%.

Examples of preferred copolymers are copolymers of from 25 to 90% by weight of acrylic acid and from 75 to 10% by weight of acrylamide. Particular preference is given to homopolymers of acrylic acid which are obtainable by free-radical polymerization of acrylic acid in the absence of other monomers and to copolymers of acrylic acid and / or methacrylic acid which are obtained by copolymerizing acrylic acid and / or methacrylic acid in the presence of pentaerythritol triallyl ether, N, N'-divinylethyleneurea, at least two allyl-containing allyl ethers of sugars such as sucrose, glucose or mannose or triallylamine and mixtures of these compounds can be produced.

The polymerization can additionally be carried out in the presence of at least one crosslinker. Copolymers having a higher molecular weight are then obtained than when the anionic monomers are polymerized in the absence of a crosslinking agent. Incorporation of a crosslinker in the polymers also results in reduced solubility of the polymers in water. Depending on the amount of copolymerized crosslinker, the polymers become water-insoluble but are swellable in water. There are fluid transitions between complete solubility of the polymers in water and swelling of the polymers in water. Crosslinked copolymers have a high water absorption capacity due to their swelling capacity in water.

Crosslinkers which can be used are all compounds which have at least two ethylenically unsaturated double bonds in the molecule. Such compounds are used, for example, in the preparation of crosslinked polyacrylic acids such as superabsorbent polymers, cf. EP-A 858 478 , Page 4, line 30 to page 5, line 43. Examples of crosslinkers are triallylamine, pentaerythritol triallether, methylenebisacrylamide, N, N'-divinylethyleneurea, allyl ethers containing at least two allyl groups or vinyl ethers of polyhydric alcohols having at least two vinyl groups, such as sorbitol, 1, 2-ethanediol, 1,4-butanediol, trimethylolpropane, glycerol, diethylene glycol and of sugars such as sucrose, glucose, mannose, completely hydrated with acrylic acid or methacrylic dihydric alcohols having 2 to 4 carbon atoms such as ethylene glycol dimethacrylate, ethylene glycol diacrylate, butanediol dimethacrylate, butanediol diacrylate, diacrylates or dimethacrylates of polyethylene glycols having molecular weights of 300 to 600, ethoxylated trimethylenepropane triacrylates or ethoxylated trimethylenepropane trimethacrylates, 2,2-bis (hydroxymethyl) butanol trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate and triallylmethylammonium chloride. If crosslinking agents are used in the preparation of the anionic dispersions, the amounts of crosslinker used in each case are, for example, 0.0005 to 5.0, preferably 0.001 to 1.0,% by weight, based on the total during the polymerization used monomers. Crosslinkers which are preferably used are pentaerythritol triallyl ether, N, N'-divinylethyleneurea, allyl ethers containing at least two allyl groups of sugars, such as sucrose, glucose or mannose and triallylamine, and also mixtures of these compounds.

The polymerization can additionally be carried out in the presence of at least one chain transfer agent. This gives polymers which have a lower molecular weight than polymers prepared without chain transfer agents. Examples of chain transfer agents are compounds containing sulfur in bound form, such as dodecylmercaptan, thiodiglycol, ethylthioethanol, di-n-butylsulfide, di-n-octylsulfide, diphenylsulfide, diisopropyldisulfide, 2-mercaptoethanol, 1,3-mercaptopropanol, 3-mercaptopropan-1 , 2-diol, 1,4-mercaptobutanol, thioglycolic acid, 3-mercaptopropionic acid, mercaptobemic acid, thioacetic acid and thiourea, aldehydes, organic acids such as formic acid, sodium formate or ammonium formate, alcohols such as in particular isopropanol and phosphorus compounds, eg Sodium. One can use a single or several chain transfer agents in the polymerization. If used in the polymerization, they are used, for example, in an amount of 0.01 to 5.0, preferably 0.2 to 1 wt .-%, based on the total monomers. The chain transfer agents are preferably used together with at least one crosslinker in the polymerization. By varying the amount and the ratio of chain transfer agent and crosslinker, it is possible to control the rheology of the resulting polymers. Chain transfer agents and / or crosslinkers may be initially charged in the polymerization, for example, in the aqueous polymerization medium or dosed together or separately from the monomers, depending on the progress of the polymerization, to the polymerization batch.

The polymerization usually uses initiators which form radicals under the reaction conditions. Suitable polymerization initiators are, for example, peroxides, hydroperoxides, hydrogen peroxide, sodium or potassium persulfate, redox catalysts and azo compounds such as 2,2-azobis (N, N-dimethyleneisobutyramidine) dihydrochloride, 2,2-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2-azobis (2,4-dimethylvaleronitrile) and 2,2-azobis (2-amidinopropane) dihydrochloride). The initiators are used in the amounts customary in the polymerization. Azo starters are preferably used as polymerization initiators. However, it is also possible to initiate the polymerization by means of high-energy rays such as electron beams or by irradiation with UV light.

The aqueous dispersions of the water-soluble anionic polymers have a polymer concentration of anionic polymers of, for example, 1 to 70 wt .-%, usually 5 to 50, preferably 10 to 25 and particularly preferably 15 to 20 wt .-%. They contain at least two different groups of the above-mentioned polymers (A) and (b) for stabilizing the anionic polymers formed in the polymerization. The amount of stabilizers (a) and (b) in the aqueous dispersion is for example 1 to 40 wt .-%, usually 5 to 30 wt .-% and preferably 10 to 25 wt .-%. The aqueous dispersions have, for example at a pH of 2.5, viscosities in the range of 200 to 100,000 mPas, preferably 200 to 20,000 mPas, preferably 200 to 10,000 mPas (measured in a Brookfield viscometer at 20 ° C, Spindle 6, 100 rpm).

The stabilizers of group (a) include graft polymers of vinyl acetate and / or vinyl propionate on (i) polyethylene glycols or (ii) on one or both sides with alkyl, carboxyl or amino end-capped polyethylene glycols or polypropylene glycols, and also polyalkylene glycols and one or both sides with alkyl, carboxyl or amino groups end-capped polyalkylene glycols.

Polyalkylene glycols are used for example in the WO 03/046024 , Page 4, line 37 to page 8, line 9 described. The polyalkylene glycols described therein can either be used directly as a stabilizer of group (a) or modified to grafted onto 100 parts by weight of the polyalkylene glycols, for example 10 to 1000, preferably 30 to 300 parts by weight of vinyl acetate and / or vinyl propionate. Polyethylene glycol having a molecular weight M _N of 1000 to 100 000 is preferably used as the grafting base, and vinyl acetate is grafted thereon.

Further suitable stabilizers (a) are the abovementioned polyalkylene glycols and the polyalkylene glycols which are end-capped on one or both sides with alkyl, carboxyl or amino groups. The abovementioned polymers have for example molar masses M _{N of} from 100 to 100,000, preferably from 300 to 80,000, particularly preferably from 600 to 50,000 and in particular from 1,000 to 50,000. Such polymers are described, for example, in the above-cited WO 03/046024 , Page 4, line 37 to page 8, line 9 described. Preferred polyalkylene glycols are, for example, polyethylene glycol, polypropylene glycol and block copolymers of ethylene oxide and propylene oxide. The block copolymers may contain copolymerized ethylene oxide and propylene oxide in any desired amounts and in any order. The OH end groups of the polyalkylene glycols may optionally be end-capped on one or both sides with alkyl, carboxyl or amino groups, with the end group preferably being a methyl group.

Particularly preferably used stabilizers of group (a) are copolymers of ethylene oxide and propylene oxide. Particularly preferred are block copolymers of ethylene oxide and propylene oxide having a molecular weight M _N of 500 to 20,000 g / mol and a content of ethylene oxide units of 10 to 80 mol%.

The water-soluble polymers of group (a), for example, in amounts of from 1 to 39.5 wt .-%, preferably 5 to 30 wt .-% and particularly preferably 10 to 25 wt .-%, based on the total dispersion, in the Preparation of the dispersions used.

• (b1) wasserlöslichen, nichtionischen, monoethylenisch ungesättigten Monomeren,
• (b2) wasserlöslichen, kationischen, monoethylenisch ungesättigten Monomeren und gegebenenfalls
• (b3) wasserlöslichen, anionischen, monoethylenisch ungesättigten Monomeren,

wobei der Anteil der einpolymerisierten kationischen Monomere größer ist als der der anionischen Monomeren.As polymers of group (b), water-soluble copolymers are used

• (b1) water-soluble, nonionic, monoethylenically unsaturated monomers,
• (b2) water-soluble, cationic, monoethylenically unsaturated monomers and optionally
• (b3) water-soluble, anionic, monoethylenically unsaturated monomers,

wherein the proportion of copolymerized cationic monomers is greater than that of the anionic monomers.

Examples of water-soluble nonionic monomers (b1) are acrylamide, methacrylamide, N-vinylformamide, N-vinylpyrrolidone and N-vinylcaprolactam. In principle, all nonionic, monoethylenically unsaturated monomers which have a water solubility of at least 100 g / l at a temperature of 20 ° C. are suitable as monomers of group (b1). Particularly preferred are monomers (b1) which are miscible with water in any ratio and form clear aqueous solutions such as acrylamide or N-vinyl-formamide.

Water-soluble, cationic, monoethylenically unsaturated monomers (b2) are, for example, dialkylaminoalkyl (meth) acrlylates such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminopropyl acrylate, dimethylaminopropyl methacrylate, diethylaminopropyl acrylate and diethylaminopropyl methacrylate, dialkyldiallyammonium halides such as dimethyldiallylammonium chloride and diethyldiallylammonium chloride, N-vinylimidazole and quaternized N-vinylimidazole. Basic monomers such as dimethylaminoethyl acrylate or dimethylaminoethyl methacrylate can be used both in the form of the free bases and in partially or completely neutralized form with acids such as hydrochloric acid, sulfuric acid, formic acid and p-toluenesulfonic acid. The basic monomers may also be partially or completely quaternized with C ₁ - to C ₁₈ -alkyl halides and / or C ₁ - to C ₁₈ -alkyl C ₁ - to C ₁₈ -alkylaryl halides and used in this form in the polymerization. Examples thereof are the dimethylaminoethyl (meth) acrylates quaternized completely with methyl chloride, such as dimethylaminoethyl acrylate methochloride or dimethylaminoethyl methacrylate methochloride. The polymers of group (b) may also contain vinylamine units as a cationic group. Such polymers are obtainable, for example, by using N-vinylformamide optionally polymerized together with at least one anionic water-soluble monomer and the polymers are then hydrolyzed with partial elimination of formyl groups to polymers containing vinylamine units.

The polymers of group (b) may optionally contain at least one anionic monoethylenically unsaturated monomer (b3) in copolymerized form. Examples of such monomers are the abovementioned anionic monomers which form water-soluble polymers such as acrylic acid, methacrylic acid, vinylsulfonic acid, vinyl-phosphonic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid and the alkali metal and ammonium salts of these acids.

• (b1) Acrylamid, Methacrylamid, N-Vinylformamid, N-Vinylpyrrolidon und/oder N-Vinylcaprolactam,
• (b2) Dialkylaminoalkylacrylat, Dialkylaminoalkylmethacrylat, partiell oder vollständig neutralisierte Dialkylaminoalkyl(meth)acrylate, quaternierte Dialkylaminoalkyl-(meth)acrylate, Dialkyldiallylammoniunhalogenide, N-Vinylimidazol und quaterniertem N-Vinylimidazol und gegebenenfalls
• (b3) Acrylsäure, Methacrylsäure, Vinylsulfonsäure, Vinylphosphonsäure, Maleinsäure, Fumarsäure, Crotonsäure, Itakonsäure sowie die Alkalimetall- und Ammoniumsalze dieser Säuren.

Examples of copolymers of group (b) are water-soluble copolymers

• (b1) acrylamide, methacrylamide, N-vinylformamide, N-vinylpyrrolidone and / or N-vinylcaprolactam,
• (b2) dialkylaminoalkyl acrylate, dialkylaminoalkyl methacrylate, partially or completely neutralized dialkylaminoalkyl (meth) acrylates, quaternized dialkylaminoalkyl (meth) acrylates, dialkyldiallylammonium halides, N-vinylimidazole and quaternized N-vinylimidazole, and optionally
• (b3) acrylic acid, methacrylic acid, vinylsulfonic acid, vinylphosphonic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid and the alkali metal and ammonium salts of these acids.

• (b1) 2 bis 90, vorzugsweise 20 bis 80 und besonders bevorzugt 35 bis 70 mol-% mindestens eines nichtionischen Monomers
• (b2) 2 bis 90, vorzugsweise 20 bis 80 und besonders bevorzugt 35 bis 70 mol% mindestens eines kationischen Monomers
  und
• (b3) 0 bis 48,9 mol-%, vorzugsweise 0 bis 30 und besonders bevorzugt 0 bis 10 mol-% mindestens eines anionischen Monomers in einpolymerisierter Form, wobei der Anteil der kationischen Monomereinheiten größer ist als der der anionischen Monomereinheiten.

The water-soluble polymers (b) contain, for example

• (b1) 2 to 90, preferably 20 to 80 and particularly preferably 35 to 70 mol% of at least one nonionic monomer
• (b2) 2 to 90, preferably 20 to 80 and particularly preferably 35 to 70 mol% of at least one cationic monomer
  and
• (b3) 0 to 48.9 mol%, preferably 0 to 30 and particularly preferably 0 to 10 mol% of at least one anionic monomer in polymerized form, wherein the proportion of the cationic monomer units is greater than that of the anionic monomer units.

Specific examples of polymers (b) are copolymers of acrylamide and dimethylaminoethyl acrylate methochloride, copolymers of acrylamide and dimethylaminoethyl methacrylate methochloride; Copolymers of acrylamide and dimethylaminopropyl acrylate methochloride, copolymers of methacrylamide and dimethylaminoethyl methacrylmethochloride, Copolymers of acrylamide, Dimethylaminoethylacrylatmethochlorid and acrylic acid, copolymers of acrylamide, Dimethylaminoethylmethacrylatmethochlorid and methacrylic acid and copolymers of acrylamide, Dimethylaminoethylacrylatmethochlorid and acrylic acid.

The polymers (b) have for example a K value of 15 to 200, preferably 30 to 150 and particularly preferably 45 to 110 (determined according to H. Fikentscher, Cellulose Chemistry, Vol. 13, 58-64 and 71-74 (1932 in 3% by weight aqueous cooking oil solution at 25 ° C, a polymer concentration of 0.1% by weight and a pH of 7). The average molecular weight of the anionic polymers which are suitable as component (b) of the stabilizer mixture is, for example, up to 1.5 million, usually up to 1 million, and is preferably in the range from 1000 to 100,000 (determined by the method of light scattering).

The aqueous dispersions contain the polymers of group (b), for example, in amounts of 0.5 to 15, preferably 1 to 10 wt .-%.

1. (a) mindestens einem Blockcoplymer aus Ethylenoxid und Propylenoxid
   und
2. (b) mindestens einem Copolymer aus Acrylamid und Dimethylaminoethylacrylatmethochlorid.

The aqueous dispersions of the anionic polymers preferably comprise as stabilizer a combination of

1. (a) at least one block copolymer of ethylene oxide and propylene oxide
   and
2. (B) at least one copolymer of acrylamide and Dimethylaminoethylacrylatmethochlorid.

The copolymer (b) may optionally contain up to 5 mol% of acrylic acid in copolymerized form.

As component (b) of stabilizer mixtures for the preparation of aqueous dispersions of water-soluble anionic polymers are in particular also hydrolyzed copolymers of vinyl alkyl ethers and maleic anhydride and the resulting from partial or complete neutralization with alkali metal and / or ammonium bases available salts of the copolymers into consideration. The alkyl group of the vinyl alkyl ethers may have, for example, 1 to 4 carbon atoms. The copolymers are obtainable by copolymerizing vinyl alkyl ethers with maleic anhydride and subsequent hydrolysis of the anhydride groups to carboxyl groups and optionally partial or complete neutralization of the carboxyl groups. Particularly preferred water-soluble polymers of group (b) are hydrolyzed copolymers of vinyl methyl ether and maleic anhydride in the form of the free carboxyl groups and in the form of at least partially neutralized with sodium hydroxide, potassium hydroxide or ammonia salts.

Further suitable water-soluble polymers of group (b) are water-soluble starches from the group of cationically modified potato starch, anionically modified potato starch, degraded potato starch and maltodextrin. Examples of cationically modified potato starches are the commercial products Amylofax 15 and Perlbond 970. A suitable anionically modified potato starch is Perfectamyl A 4692. Here the modification consists essentially in a carboxylation of potato starch. C * Pur 1906 is an example of an enzymatically degraded potato starch and maltodextrin C 01915 for a hydrolytically degraded potato starch. Of the mentioned starches, maltodextrin is preferably used.

Other preferably used polymers of component (b) of the stabilizer mixtures are homopolymers and copolymers having molecular weights M _w up to 100 000 of anionic monomers, for example homopolymers of ethylenically unsaturated C ₃ - to C ₅ -carboxylic acids such as in particular homopolymers of acrylic acid or methacrylic acid, or other acid group-containing monomers such as acrylamidomethylpropanesulfonic acid, styrenesulfonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, vinylsulfonic acid and vinylphosphonic acid and the alkali metal and ammonium salts of the acid group-containing monomers. The said anionic monomers may be partially or completely neutralized. Also suitable as component (b) of the stabilizer mixtures are copolymers of anionic monomers, for example copolymers of acrylic acid and methacrylic acid, copolymers of acrylic acid and maleic acid, copolymers of methacrylic acid and maleic acid, and copolymers of acrylic acid and itaconic acid.

Further suitable polymers which are used as component (b) of the stabilizer mixtures are copolymers of (i) anionic and (ii) cationic and optionally (iii) neutral monomers, the proportion of copolymerized anionic monomers being greater than that of the cationic monomers. As (i) anionic monomers, the monomers mentioned in the preceding paragraph can be used. Particularly preferred are acrylic acid, methacrylic acid, maleic acid and acrylamidomethylpropanesulfonic acid.

Examples of (ii) cationic monomers are water-soluble, cationic, monoethylenically unsaturated monomers which are already mentioned above in the case of the stabilizers (b) under (b2) which carry a cationic charge, for example dialkylaminoalkyl (meth) acrlylates in the form of the salts with acids or in quaternized form, dialkyldiallyammonium halides such as dimethyldiallylammonium chloride and diethyldiallylammonium chloride, quaternized N-vinylimidazole.

Examples of (iii) neutral monomers are all esters of monohydric C ₁ to C ₁₈ monohydric alcohols, styrene, N-vinylpryrrolidone, N-vinylimidazole, N-vinylformamide, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, vinyl acetate and vinyl propionate.

Further suitable as component (b) of stabilizer mixtures polymers are copolymers of (i) at least one anionic monomer (such monomers are already exemplified above) and (ii) at least one neutral monomer selected from the group of esters of anionic monomers with monohydric alcohols, styrene , N-vinylpryrrolidone, N-vinylimidazole, N-vinylformamide, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, vinyl acetate and vinyl propionate. Particularly preferred from this group (b) are copolymers of acrylic acid and methyl acrylate and copolymers of acrylic acid, acrylamidomethylpropanesulfonic acid, methyl acrylate and styrene.

The molecular weights M _{w of} the abovementioned polymers are, for example, in the range from 1,000 to 100,000, preferably 1,500 to 70,000 and usually 2,000 to 30,000 (determined by light scattering).

The ratio of components (a) and (b) in the stabilizer mixtures can be varied within a wide range. For example, it can be 50: 1 to 1:10. It is preferable to choose a ratio of (a) :( b) of at least 1.5: 1, in particular from 7: 1 to 10: 1.

The stable aqueous dispersions of water-soluble anionic polymers obtainable in this way have, for example, a particle size of 0.1 to 200 .mu.m, preferably 0.5 to 70 .mu.m. The particle size can be z. As determined by optical microscopy, light scattering or freeze-fracture electron microscopy. The aqueous dispersions are prepared, for example, at pH values of 0.5 to 5, preferably 1 to 3. At pH values below 5, dispersions containing about 5 to 35% by weight of anionic polymers have a relatively low viscosity.

For use as an extinguishing agent additive, however, a higher viscosity of the extinguishing agent is desired. Upon dilution of the aqueous dispersions of water-soluble or water-swellable dispersions obtainable in this way with water and in particular in the case of partial or complete neutralization of the anionic groups of the polymers, a marked increase in viscosity is achieved. For the use according to the invention as an extinguishing agent additive, therefore, the aqueous polymer dispersion is used together with at least one neutralizing agent. Suitable neutralizing agents are, for example, an alkali metal, alkaline earth metal and / or ammonium base Consideration. Particularly preferred neutralizing agents are sodium hydroxide solution, potassium hydroxide solution, ammonia, ethanolamine, diethanolamine or triethanolamine. In addition, all other amines or polyamines such as diethylenetriamine, triethylenetetramine, polyethyleneimines and / or polyvinylamines can be used as neutralizing agent.

The amount of neutralizing agent used depends essentially on the desired viscosity that the quenching medium is to have. This viscosity is dependent on the pH of the extinguishing agent, which is preferably in the range of 7.5 to 11. A preferred embodiment of the invention consists of continuously mixing with water an aqueous dispersion of water-soluble and / or water-swellable anionic polymers and at least one water-soluble neutralizing agent such that the mixture, i. the extinguishing agent, a polymer content of at most 5 wt .-%, for example, 0.1 to 2.5 wt .-%, usually 1.0 to 2.0 wt .-%, and a pH of at least 5.5 and has a viscosity of at most 100,000 mPas (Brookfield viscometer, spindle V40203T01, 20 rpm 23 ° C).

Particular preference is given to using aqueous dispersions of anionic polymers which are crosslinked. The crosslinking agent is most often used during the polymerization to give polymer particles that are cross-linked throughout. However, it is also possible to use the crosslinking agent for surface post-crosslinking of the dispersed polymer particles by post crosslinking following the main polymerization, and the main polymerization can be carried out in the presence of a crosslinker.

1. (1) mit ETMPTA (ethyoxyliertes Trimethylolpropantriacrylat) vernetze Polyacrylsäure, Stabilisator aus (a) Pfropfpolymerisat von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6000 und (b) Copolymer aus Vinylmethylether und Maleinsäure;Viskosität der Emulsion: 5 350 m Pas;
2. (2) mit Triallylamin vernetze Polyacrylsäure, Stabilisator aus (a) Pfropfpolymerisat von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6000 und (b) Copolymer aus Vinylmethylether und Maleinsäure; Viskosität der Emulsion: 10 250 m Pas;
3. (3) Copolymerisat aus 135 Gew.-Teilen Acrylsäure und 15 Gew.-Teilen Methylacrylat, vernetzt mit 1,5 Gew.-Teilen Triallylamin, Stabilisator aus (a) Pfropfpolymerisat von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6000 und (b) Copolymer aus Vinylmethylether und Maleinsäure; Viskosität der Emulsion: 5 800 mPas;
4. (4) Copolymerisat aus 142,5 Gew.-Teilen Acrylsäure und 7,5 Gew.-Teilen Methylacrylat, vernetzt mit 1,5 Gew.-Teilen Triallylamin, Stabilisator aus (a) Pfropfpolymerisat von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6000 und (b) Copolymer aus Vinylmethylether und Maleinsäure;Viskosität der Emulsion: 21 900 m Pas;
5. (5) Polymerisat aus 174 Gew.-Teilen Acrylsäure und 1 Gew.-Teil Pentaerythrittriallylether (70 gew.%ig in Wasser), Stabilisator aus (a) 175 g eines Copolymers aus 20,3 Gew.-Teilen Propylenoxid und 14,2 Gew.-Teilen Ethylenoxid und (b) 62,5 Gew.-Teilen einer 40 gew.-%igen wässrigen Lösung eines Copolymerisates aus 95 Gew.-Teilen Vinylimidazol, das mit Methylchlorid quaterniert ist, und 5 Gew.-Teilen N-Vinylpyrrolidon; Viskosität der Emulsion: 1 200 mPas;
6. (6) Polymerisat aus 174 Gew.-Teilen Acrylsäure und 1 Gew.-Teil Pentaerythrittriallylether (70 gew.-%ig in Wasser), Stabilisator aus (a) 175 g eines Copolymers aus 20,3 Gew.-Teilen Propylenoxid und 14,2 Gew.-Teilen Ethylenoxid und (b) 37,5 Gew.-Teilen einer 40 gew.-%igen wässrigen Lösung eines Copolymerisates aus 50 Gew.-Teilen Vinylimidazol, das mit Methylchlorid quaterniert ist, und 50 Gew.-Teilen N-Vinylpyrrolidon; Viskosität der Emulsion: 1 850 mPas;
7. (7) Polyacrylsäure erhältlich durch Polymerisieren von 30 Gew.-Teilen Acrylsäure in Gegenwart von Stabilisator aus (a) 19 Gew.-Teilen eines Pfropfpolymerisates von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6 000 und (b) 17 Gew.-Teilen eines hydrolysierten Copolymerisates aus Maleinsäureanhydrid und Vinylmethylether; Viskosität der Emulsion: 5 950 m Pas;
8. (8) Polymerisat aus 30 Gew.-Teilen Acrylsäure und 0,09 Gew.-Teilen Triallylamin, polymerisiert in Gegenwart eines Stabilisators aus (a) 19 Gew.-Teilen eines Pfropfpolymerisates von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6 000 und (b) 17 Gew.-Teilen eines hydrolysierten Copolymerisates aus Maleinsäureanhydrid und Vinylmethylether; Viskosität der Emulsion: 2 700 m Pas;
9. (9) Homopolymerisat der Acrylsäure aus 30 Gew.-Teilen Acrylsäure, polymerisiert in Gegenwart eines Stabilisators aus (a) 12 Gew.-Teilen Polyethylenglykol der Molmasse M_w 600 und (b) 17 Gew.-Teilen eines hydrolysierten Copolymerisates aus Maleinsäureanhydrid und Vinylmethylether; Viskosität der Emulsion: 2 240 m Pas;
10. (10) Homopolymerisat der Acrylsäure aus 30 Gew.-Teilen Acrylsäure, polmyerisiert in Gegenwart eines Stabilisators aus (a) 1,5 Gew.-Teilen Polyethylenglykol der Molmasse 900, 16,5 Gew.-Teilen Polyethylenglykol der Molmasse 600 und (b) 18 Gew.-Teilen Polyethylenimin M_w von 25000, Viskosität der Emulsion: 208 mPas;
11. (11) Homopolymerist der Acrylsäure aus 30 Gew.-Teilen Acrylsäure, polymerisiert in Gegenwart eines Stabilisators aus (a) Ester aus Methylpolyethylenglykol des mittleren Molekulargewichts M_w 1000 und Methacrylsäure, der mit dem Na-Salz der Methacrylsäure gepfropft ist, und (b) 17 Gew.-Teilen eines hydrolysierten Copolymerisates aus Maleinsäureanhydrid und Vinylmethylether; Viskosität der Emulsion: 3 650 m Pas;
12. (12) vernetzte Polyacrylsäure aus 30 Gew.-Teilen Acrylsäure und 0,22 Gew.-Teilen Pentaerythrittriallylether (70 %ig), polymerisiert in Gegenwart eines Stabilisators aus (a) 19 Gew.-Teilen eines Pfropfpolymerisates von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6 000 und (b) 17 Gew.-Teilen eines hydrolysierten Copolymerisates aus Maleinsäureanhydrid und Vinylmethylether; Viskosität der Emulsion: 2 900 m Pas;
13. (13) Homopolymerisat der Acrylsäure aus 30 Gew.-Teilen Acrylsäure, polymerisiert in Gegenwart eines Stabilisators aus (a) 19 Gew.-Teilen eines Pfropfpolymerisates von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6 000 und (b) 18 Gew.-Teilen Maltodextrin; Viskosität der Emulsion: 10 500 m Pas;
14. (14) vernetzte Polyacrylsäure aus 30 Gew.-Teilen Acrylsäure und 0,09 Gew.-Teilen Triallylamin, polymerisiert in Gegenwart eines Stabilisators aus (a) 19 Gew.-Teilen eines Pfropfpolymerisates von Vinylacetat auf Polyethylenglykol der Molmasse M_w 6 000 und (b) 17 Gew.-Teilen eines hydrolysierten Copolymerisates aus Maleinsäureanhydrid und Vinylmethylether; Viskosität der Emulsion: 3 700 m Pas;
15. (15) Homopolymerisat der Acrylsäure aus 30 Gew.-Teilen Acrylsäure, polymerisiert in Gegenwart eines Stabilisators aus (a) 18 Gew.-Teilen Butylpolyalkylenglykolcopolymer M_w 2000 (Pluriol A2000 PE) und (b) 18 Gew.-Teilen Polyethylenimin M_w 25000; Viskosität der Emulsion: 320 m Pas;

Aqueous polymer dispersions to be used according to the invention may comprise, for example, the following anionic polymers and be prepared in the presence of the stabilizer components (a) and (b) indicated below. The viscosities of the aqueous dispersions of water-soluble or water-swellable polymers (hereinafter referred to as "emulsion") given in the following overview were measured in a Brookfield R / S rheometer, spindle V 40203T01, at 20 rpm and a temperature of 23 ° C.

1. (1) ETMPTA (ethyoxylated trimethylolpropane triacrylate) crosslinked polyacrylic acid, stabilizer of (a) graft polymer of vinyl acetate on polyethylene glycol of molecular weight M _w 6000 and (b) copolymer of vinyl methyl ether and maleic acid; viscosity of the emulsion: 5 350 m Pas;
2. (2) crosslinked with triallylamine polyacrylic acid, stabilizer of (a) graft polymer of vinyl acetate on polyethylene glycol of molecular weight M _w 6000 and (b) copolymer of vinyl methyl ether and maleic acid; Viscosity of the emulsion: 10 250 m Pas;
3. (3) Copolymer of 135 parts by weight of acrylic acid and 15 parts by weight of methyl acrylate crosslinked with 1.5 parts by weight of triallylamine, stabilizer of (a) graft polymer of vinyl acetate on polyethylene glycol of molecular weight M _w 6000 and (b) copolymer from vinyl methyl ether and maleic acid; Viscosity of the emulsion: 5,800 mPas;
4. (4) Copolymer of 142.5 parts by weight of acrylic acid and 7.5 parts by weight of methyl acrylate, crosslinked with 1.5 parts by weight of triallylamine, stabilizer of (a) graft polymer of vinyl acetate on polyethylene glycol of molecular weight M _w 6000 and (b) copolymer of vinyl methyl ether and maleic acid; viscosity of the emulsion: 21,900 m Pas;
5. (5) polymer of 174 parts by weight of acrylic acid and 1 part by weight of pentaerythritol triallyl ether (70% strength by weight in water), stabilizer of (a) 175 g of a copolymer of 20.3 parts by weight of propylene oxide and 14.2 Parts by weight of ethylene oxide and (b) 62.5 parts by weight of a 40% strength by weight aqueous solution of a copolymer of 95 parts by weight of vinylimidazole quaternized with methyl chloride and 5 parts by weight of N-vinylpyrrolidone ; Viscosity of the emulsion: 1,200 mPas;
6. (6) polymer of 174 parts by weight of acrylic acid and 1 part by weight of pentaerythritol triallyl ether (70% strength by weight in water), stabilizer of (a) 175 g of a copolymer of 20.3 parts by weight of propylene oxide and 14, 2 parts by weight of ethylene oxide and (b) 37.5 parts by weight of a 40% strength by weight aqueous solution of a copolymer of 50 parts by weight of vinylimidazole quaternized with methyl chloride and 50 parts by weight of N- vinylpyrrolidone; Viscosity of the emulsion: 1 850 mPas;
7. (7) Polyacrylic acid obtainable by polymerizing 30 parts by weight of acrylic acid in the presence of stabilizer from (a) 19 parts by weight of a graft polymer of vinyl acetate on polyethylene glycol of molecular weight M _w 6,000 and (b) 17 parts by weight of a hydrolyzed Copolymers of maleic anhydride and vinyl methyl ether; Viscosity of the emulsion: 5,950 m Pas;
8. (8) polymer of 30 parts by weight of acrylic acid and 0.09 parts by weight of triallylamine, polymerized in the presence of a stabilizer of (a) 19 parts by weight of a graft polymer of vinyl acetate on polyethylene glycol of molecular weight M _w 6 000 and (b 17 parts by weight of a hydrolyzed copolymer of maleic anhydride and vinyl methyl ether; Viscosity of the emulsion: 2,700 m Pas;
9. (9) homopolymer of acrylic acid from 30 parts by weight of acrylic acid, polymerized in the presence of a stabilizer of (a) 12 parts by weight of polyethylene glycol Molecular weight M _w 600 and (b) 17 parts by weight of a hydrolyzed copolymer of maleic anhydride and vinyl methyl ether; Viscosity of the emulsion: 2 240 m Pas;
10. (10) homopolymer of acrylic acid from 30 parts by weight of acrylic acid, polymerized in the presence of a stabilizer of (a) 1.5 parts by weight of polyethylene glycol of molecular weight 900, 16.5 parts by weight of polyethylene glycol of molecular weight 600 and (b) 18 parts by weight of polyethylenimine M _w of 25,000, viscosity of the emulsion: 208 mPas;
11. (11) Homopolymer of acrylic acid from 30 parts by weight of acrylic acid polymerized in the presence of a stabilizer of (a) ester of methylpolyethylene glycol of average molecular weight M _w 1000 and methacrylic acid grafted with the Na salt of methacrylic acid, and (b) 17 parts by weight of a hydrolyzed copolymer of maleic anhydride and vinyl methyl ether; Viscosity of the emulsion: 3 650 m Pas;
12. (12) crosslinked polyacrylic acid from 30 parts by weight of acrylic acid and 0.22 parts by weight of pentaerythritol triallyl ether (70%), polymerized in the presence of a stabilizer of (a) 19 parts by weight of a graft polymer of vinyl acetate on polyethylene glycol of molecular weight M. _w 6,000 and (b) 17 parts by weight of a hydrolyzed copolymer of maleic anhydride and vinyl methyl ether; Viscosity of the emulsion: 2,900 m Pas;
13. (13) homopolymer of acrylic acid from 30 parts by weight of acrylic acid, polymerized in the presence of a stabilizer of (a) 19 parts by weight of a graft polymer of vinyl acetate on polyethylene glycol of molecular weight M _w 6 000 and (b) 18 parts by weight of maltodextrin ; Viscosity of the emulsion: 10,500 m Pas;
14. (14) crosslinked polyacrylic acid from 30 parts by weight of acrylic acid and 0.09 parts by weight of triallylamine polymerized in the presence of a stabilizer of (a) 19 parts by weight of a graft polymer of vinyl acetate on polyethylene glycol of molecular weight M _w 6 000 and ( b) 17 parts by weight of a hydrolyzed copolymer of maleic anhydride and vinyl methyl ether; Viscosity of the emulsion: 3,700 m Pas;
15. (15) acrylic acid homopolymer of 30 parts by weight of acrylic acid polymerized in the presence of a stabilizer of (a) 18 parts by weight butyl polyalkylene glycol copolymer M _w 2000 (Pluriol A2000 PE) and (b) 18 parts by weight polyethyleneimine M _w 25,000 ; Viscosity of the emulsion: 320 m Pas;

The emulsions give in the application according to the invention clear gels, which are storage stable even at higher temperatures. They are liable to fire fighting on vertical surfaces and effectively hinder too fast evaporation of the fire-fighting water. They are particularly suitable in extinguishing water, which is discharged from a greater height to a fire, e.g. from a helicopter.

The viscosities reported in the examples were measured in a Brookfield R / S Rheometer, spindle V 40203T01, at 20 rpm and a temperature of 23 ° C. The parts mean parts by weight.

Examples (a) Preparation of an aqueous dispersion of crosslinked polyacrylic acid

In a polymerization apparatus; which was equipped with a stirrer and a device for working under a nitrogen atmosphere, were 175 g of a copolymer of 20.3 parts of propylene oxide and 14.2 parts of ethylene oxide, 95.6 g of a 20.92% aqueous solution of a copolymer of 35 mol% of acrylamide and 65 mol% of dimethylaminoethyl acrylate methochloride and 513.9 g of completely demineralized water. The mixture was stirred continuously and flooded first with nitrogen for 10 minutes. Then, within 10 minutes, 174 g of acrylic acid and 1.0 g of pentaerythritol triallyl ether (70% strength) were metered in. Thereafter, 0.2 g of azo starter VA 044 [2,2'-azobis (N, N'-dimethyleneisobutyramidine) dihydrochloride] in 10 g of completely demineralized water was added and rinsed with 10 g of water. The reaction mixture was then heated to a temperature of 40 ° C with continuous passage of nitrogen and polymerized at this temperature for 5 hours. Thereafter, 0.3 g of azo starter VA 044 in 10 g of completely deionized water was added, rinsed with 10 g of completely deionized water and the reaction mixture was stirred for 2 hours at 40 ° C for postpolymerization. This gave a white emulsion which had a viscosity of 1200 mPas. It will be referred to below as Dispersion A.

(b) neutralization and dilution of the aqueous dispersion obtained according to (a) example 1

10 g of dispersion A were added with stirring to an aqueous solution of 50 g of triethanolamine in 150 g of completely deionized water. A clear sample was obtained which had a pH of 9.1 and a viscosity of 35,000 mPas (measured at 20 rpm). The viscosity of this sample was 7 900 mPas at 150 rpm under otherwise identical measuring conditions.

Example 2

20 g of triethanolamine and then 10 g of dispersion A were added, with constant stirring, to 180 g of completely demineralized water, giving a clearly dissolved sample which had a pH of 9.5 and a viscosity of 36,500 mPas (measured at 20 rpm ) would have. The viscosity of this sample was 8,700 mPas at 150 rpm under otherwise identical measuring conditions.

Example 3

10 g of triethanolamine and then 10 g of dispersion A were added to 190 g of completely demineralized water, with constant stirring. An extinguishing agent having a pH of 8.7 and a viscosity of 26,800 mPas (measured at 20 rpm) was obtained , The viscosity of this sample was 6,800 mPas at 150 rpm under otherwise identical measuring conditions. Such mixtures are pumpable.

Example 4

10 g of triethanolamine and then 4 g of dispersion A were added to 180 g of completely demineralized water, with constant stirring. An extinguishing agent having a pH of 9.2 and a viscosity of 36,500 mPas (measured at 20 rpm) was obtained , The viscosity of this sample was 8,700 mPas at 150 rpm under otherwise identical measuring conditions.

Example 5

30 g of triethanolamine and then 6 g of dispersion A were added to 170 g of completely demineralized water, with constant stirring. A clearly dissolved sample having a pH of 9.5 and a viscosity of 36,500 mPas (measured at 20 rpm) was obtained ) would have. The viscosity of this sample was 8,700 mPas at 150 rpm under otherwise identical measuring conditions.

Example 6

In each case samples of aqueous extinguishing agents which were prepared according to Examples 4 and 5, stored under the conditions given in Table 1 (temperatures and times) and then each determined the viscosity of the stored samples. The measurement results are given in Table 1. They show that the extinguishing agents to be used according to the invention can be stored for a longer period of time without noticeable reduction in viscosity. Table 1 The viscosities indicated in the table were measured with a Brookfield R / S Rheometer, spindle V 40203T01, at 150 rpm and a temperature of 23 ° C. Samples obtained according to Example 4 Duration of storage [h] Viscosity [mPas] of the sample before storage after storage 0 3300 1 3378 4267 4342 24 4296 3602 3020 120 3178 2994 2753 Samples obtained according to Example 5 Duration of storage [h] Viscosity [mPas] of the sample before storage after storage 0 5311 1 6005 5977 6190 24 6234 5187 4711 120 4797 4441 3336

Claims (16)

1. The use of aqueous dispersions of water-soluble and/or water-swellable anionic polymers and water-soluble neutralizing agents as an additive to aqueous extinguishing agents.
2. The use according to claim 1, wherein an aqueous dispersion of a water-soluble and/or water-swellable anionic polymer is diluted with water to a polymer concentration of not more than 5% by weight and adjusted to a pH of at least 5.5 with at least one water-soluble neutralizing agent.
3. The use according to claim 1 or 2, wherein the pH of the aqueous extinguishing agent is from 6 to 13.
4. The use according to any of claims 1 to 3, wherein the pH of the aqueous extinguishing agent is from 7 to 12.
5. The use according to any of claims 1 to 4, wherein the polymer concentration of the aqueous extinguishing agent is from 0.01 to 2.5% by weight.
6. The use according to any of claims 1 to 5, wherein the polymer concentration of the aqueous extinguishing agent is from 0.1 to 2.0% by weight.
7. The use according to any of claims 1 to 6, wherein aqueous dispersions of water-soluble and/or water-swellable anionic polymers are used, which dispersions are obtainable by polymerization of water-soluble anionic monomers from the group consisting of the ethylenically unsaturated C₃- to C₅-carboxylic acids, vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, vinylsulfonic acid and/or the alkali metal or ammonium salts thereof in an aqueous solution which comprises at least one other polymer and, if appropriate, at least one neutral salt as a stabilizer for the polymer dispersion formed.
8. The use according to any of claims 1 to 6, wherein aqueous dispersions of water-soluble and/or water-swellable anionic polymers are used, which dispersions are obtainable by polymerization of water-soluble anionic monomers in an aqueous solution which is free of neutral salts and comprises, as a stabilizer, at least one other water-soluble polymer from the group consisting of the polyethylene glycols, polypropylene glycols, polyvinyl acetates, polyvinyl alcohols, polyvinylimidazoles, water-soluble starches, thermally, oxidatively or enzymatically degraded starches, cationically or anionically modified starches, maltodextrin and polydiallyldimethylammonium chloride.
9. The use according to any of claims 1 to 6, wherein water-soluble and/or water-swellable anionic polymers are used which are obtainable by polymerization of water-soluble anionic monomers in an aqueous solution which is free of neutral salts and comprises, as a stabilizer, at least one water-soluble polymer from the groups consisting of

   (a) graft polymers of vinyl acetate and/or vinyl propionate on polyethylene glycols, polyethylene glycols endcapped at one or both ends with alkyl, carboxyl or amino groups, copolymers of alkylpolyalkylene glycol acrylates or alkylpolyalkylene glycol methacrylates and acrylic acid and/or methacrylic acid, polyalkylene glycols having molar masses M_N of from 1000 to 100 000, and polyalkylene glycols endcapped at one or both ends with alkyl, carboxyl or amino groups and having molar masses M_N of from 1000 to 100 000
   and

   (b) hydrolyzed copolymers of vinyl alkyl ethers and maleic anhydride in the form of the free carboxyl groups and in the form of the salts at least partly neutralized with alkali metal hydroxides or ammonium bases, and/or a water-soluble starch from the group consisting of cationically modified potato starch, anionically modified potato starch, degraded potato starch and maltodextrin.
10. The use according to any of claims 1 to 6, wherein aqueous dispersions of water-soluble and/or water-swellable anionic polymers are used, which dispersions are obtainable by polymerization of water-soluble anionic monomers in an aqueous solution which is free of neutral salts and comprises, as a stabilizer, at least one water-soluble polymer from the groups consisting of

    (a)graft polymers of vinyl acetate and/or vinyl propionate on (i) polyethylene glycols or (ii) polyethylene glycols or polypropylene glycols endcapped at one or both ends with alkyl, carboxyl or amino groups, polyalkylene glycols, and polyalkylene glycols endcapped at one or both ends with alkyl, carboxyl or amino groups
    and

    (b) water-soluble copolymers of

    (b1)nonionic monoethylenically unsaturated monomers,

    (b2) cationic monoethylenically unsaturated monomers and, if appropriate,

    (b3) anionic monoethylenically unsaturated monomers, the proportion of the cationic monomers incorporated in the form of polymerized units being greater than that of the anionic monomers.
11. The use according to any of claims 1 to 6, wherein aqueous dispersions of water-soluble and/or water-swellable anionic polymers are used, which dispersions are obtainable by polymerization of water-soluble anionic monomers in an aqueous solution which is free of neutral salts and comprises, as a stabilizer, at least one water-soluble polymer from the groups consisting of

    (a) graft polymers of vinyl acetate and/or vinyl propionate on (i) polyethylene glycols or (ii) polyethylene glycols or polypropylene glycols endcapped at one or both ends with alkyl, carboxyl or amino groups, polyalkylene glycols, and polyalkylene glycols endcapped at one or both ends with alkyl, carboxyl or amino groups
    and

    (b)

    (i) homo- and copolymers of anionic monomers,

    (ii) copolymers of anionic and cationic and, if appropriate, neutral monomers, the proportion of the anionic monomers incorporated in the form of polymerized units being greater than that of the cationic monomers, and

    (iii) copolymers of at least one anionic monomer and at least one monomer from the group consisting of the esters of anionic monomers with monohydric alcohols, styrene, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinylformamide, acrylamide, methacrylamide, vinyl acetate and vinyl propionate.
12. The use according to any of claims 1 to 11, wherein the neutralizing agent used is at least one alkali metal, alkaline earth metal or ammonium base.
13. The use according to any of claims 1 to 12, wherein the neutralizing agent used is sodium hydroxide solution, potassium hydroxide solution, ammonia, ethanolamine, diethanolamine or triethanolamine.
14. The use according to any of claims 1 to 13, wherein the aqueous extinguishing agent additionally comprises at least one flameproofing agent, one dye and/or one wetting agent.
15. The use according to any of claims 1 to 14, wherein an aqueous dispersion of water-soluble and/or water-swellable anionic polymers and at least one water-soluble neutralizing agent are mixed in each case continuously with water so that the mixture has a polymer content of not more than 5% by weight and a pH of at least 5.5 and a viscosity of more than 100 000 mPa.s (Brookfield viscometer, spindle V40203T01, 20 rpm, 23°C).
16. A method for fighting fires with aqueous extinguishing agents which comprise at least one polymer, wherein an aqueous dispersion of water-soluble and/or water-swellable anionic polymers and at least one water-soluble neutralizing agent are mixed in each case continuously with water so that the mixture has a polymer content of not more than 5% by weight and a pH of at least 5.5 and said mixture is used immediately for fire fighting.