EP1539845A1

EP1539845A1 - Ecofriendly cationic polyelectrolytes

Info

Publication number: EP1539845A1
Application number: EP03755548A
Authority: EP
Inventors: Norbert Steiner; Gregor Herth; Werner Fischer; Horst Redlof
Original assignee: Stockhausen GmbH and Co KG; Chemische Fabrik Stockhausen GmbH
Current assignee: Ineos Composites IP LLC
Priority date: 2002-08-30
Filing date: 2003-07-30
Publication date: 2005-06-15
Also published as: DE10240797A1; RU2005109152A; US20050242045A1; AU2003273393A1; RU2321599C2; US7375173B2; WO2004020490A1

Abstract

The invention relates to cationic water-soluble polyelectrolytes, especially terpolymers, which are obtained by polymerising monomers of (meth)acrylamide, a quaternised (meth)acrylamide derivative, a (meth)acrylic acid derivative and/or hydrolysis-stable cationic monomers. The composition of the polyelectrolytes is characterised by a toxicity index formula Fi = (QTP- 2QME)/10 <= 1 WHEREIN QTP represents the total cationic charge of the polymer and QME represents the charge part of the ester type monomer. The invention also relates to the production and use of said polyelectrolytes and water-in-water polymer dispersions which contain said polyelectrolytes.

Description

Cationic polyelectrolytes with good environmental compatibility

The present invention relates to cationic water-soluble polyelectrolytes, in particular terpolymers of (meth) acrylamide, monomers based on cationic (meth) acrylic esters and monomers based on (meth) acrylamides and / or hydrolysis-stable cationic monomers, their preparation and use, and water-in Water-polymer dispersions containing such polyelectrolytes.

Polymers made from non-ionic, anionic and cationic vinyl polymers are used as flocculants in wastewater treatment, ore and coal processing, and in paper manufacture. Of particular importance here are water-soluble, cationic polyelectrolytes, which are used in large quantities worldwide in water treatment plants, in particular to improve the flocculation and dewatering of the resulting sewage sludge, and generally polymers from cationized acrylic acid derivatives or methacrylic acid esters or copolymers of these esters from acrylamide are.

DE 35 44 909 describes copolymers of dimethylaminopropylacrylamide (DI-MAPA) and acrylamide (AA) in which the DIMAPA is either neutralized with mineral acids or quaternized with quaternizing agents and a proportion of cationic monomers between 4 and 80 mol% and have a quotient of viscosity and molar proportion of cationic component of greater than 200. Such copolymers are characterized by very good storage and hydrolysis stability and therefore have advantages in sludge dewatering.

DE 199 41 072 describes a process for the continuous production of at least one monomer, with at least one parameter influencing the polymerization being changed in accordance with a recurring pattern. According to the procedure described, i.a. Copolymers and also terpolymers can be obtained by polymerizing the monomers (meth) acrylamide and monomers based on (meth) acrylic acid esters and (meth) acrylamides.

EP 0 649 820 describes terpolymers of acrylamide, acrylic acid and cationic monomers in combination with alkaline earth metal salts and their use in

BESTÄTIGUNGSKOPCE Sludge dewatering. The sludge dewatering agents produced from this have an improved solubility and storage stability.

No. 4,889,887 describes terpolymers of (meth) acrylamide, monomers based on (meth) acrylic esters and monomers based on (meth) acrylamides, which are used as constituents of acidic thickeners and their use in oil and natural gas production is described. HCl is added to terpolymers in order to crosslink them.

As can be seen from DE 35 44 909 already mentioned above, the polymers usually used for flocculation based on cationized (meth) acrylic acid esters have a number of disadvantages:

In particular, the shelf life of such polymers is very limited because dilute 0.1 to 0.3% aqueous solutions have to be prepared from these polymers for use as flocculants. Such solutions are not very durable due to the hydrolysis-prone ester groups in the polymers. For example, the document reports that the stability of acrylic derivatives in solution waters with pH values from 7.0 to 7.5 is only a few hours and that of methacrylic derivatives is approximately 24 hours.

In order to maintain the application properties and storage stability due to this hydrolysis instability, it is known to use products with such copolymers - for example dimethylammonium ethyl (meth) acrylate (ADAME quat), which is quaternized with methyl chloride or other ester-based cationic ones Monomers to add an organic or inorganic acid. Despite this measure, the activity of the solutions of such polymers decreases very quickly. The half-life here is only two to three days. Therefore, users who have e.g. Interrupt the dosing over the weekend, especially in the case of chamber filter press problems, to process the solution at a later time

Another disadvantage of such cationic polyelectrolytes is that they have a high acute aquatic toxicity depending on the charge density. From a charge of approx. 15% by weight, the fish toxicity of such polymers is <10 mg / l (OECD 203). For example, quaternized (meth) acrylamide-based copolymers have from one Cation activity of 20% by weight is so high in aquatic toxicity that such products can be labeled as environmentally hazardous. Chang et al. were able to show, however, that polymers based on quaternized (meth) acrylic acid esters are converted into the corresponding anionic polymers by hydrolysis, which have a significantly lower toxicity (cf. Chang et al., "Water Science Technology", vol. 44, no 2-3, 461-468, 2001).

It was therefore an object of the present invention to provide more environmentally compatible polymers which can be used for dewatering sewage sludge, drinking water treatment or paper production, which dissolve quickly and completely in an aqueous medium, are highly effective in use and have good storage stability, which Disadvantages of a rapid loss of effectiveness do not have and can be completely broken down into low-toxic products within a few days.

It has surprisingly been found that this object can be achieved by cationic water-soluble polyelectrolytes, in particular terpolymers, which can be obtained by polymerizing the monomers of (meth) acrylamide, a quaternized (meth) acrylamide derivative and a (meth) acrylic acid derivative and / or hydrolysis-stable cationic monomers , the composition of the polyelectrolytes by a toxicity index

with Q _T p = total cationic charge of the polymer Q _ME = charge fraction of the ester-type monomer.

Q _T p = total cationic charge of the polymer in the context of the present invention is understood to mean the molar fraction in mol% of all cationic monomers in the polymer.

Q _ME = charge fraction of the ester type monomer in the sense of the present invention is understood to mean the molar fraction in mol% of the ester type monomer in the polymer. The polyelectrolytes according to the invention have a total charge of 1 to 100 mol%, preferably 8 to 90 and particularly preferably 20 to 80 mol%, with a solution viscosity measured as a 1% solution in 10% NaCl solution of 10 to 2000 mPas, preferably 80 to 1500 mPas and particularly preferably have a solution viscosity of 100 to 1200 mPas.

Polyelectrolytes which contain 0.1 to 30% by weight, preferably 3 to 25% by weight and particularly preferably 7 to 20% by weight of a high-cationic, low-molecular weight polyelectrolyte are particularly preferred.

According to the invention, cationic monomers based on (meth) acrylic acid esters are preferably cationized esters of (meth) acrylic acid which contain a quaternized N atom. Quaternized dialkylaminoalkyl (meth) acrylates with d to C ₃ in the alkyl or alkylene groups are preferably used. Ammonium salts of dimethylamino-methyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminomethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and diethylaminopropyl (meth) acrylate in particular quaternized with methyl chloride. Dimethylaminoethyl acrylate which is quaternized with an alkyl halide, in particular with methyl chloride or benzyl chloride or dimethyl sulfate (ADAME quat), is particularly preferred.

Monomers based on (meth) acrylamides which contain a quaternized N atom are used as cationic monomers. Quaternized dialkylaminoalkyl (meth) acrylamides with C 1 -C ₃ in the alkyl or alkylene groups are preferably used. Dimethylaminopropylacrylamide which is quaternized with an alkyl halide, in particular methyl chloride or benzyl chloride or dimethyl sulfate, is particularly preferred.

In addition to the dialkylaminoalkyl (meth) acrylamides described above, hydrolysis-stable cationic monomers can be all monomers which are to be regarded as stable according to the hydrolysis test according to OECD, such as, for example, diallyldimethylammonium chloride or water-soluble, cationic styrene derivatives. According to the invention, particularly preferred as cationic polyelectrolytes are terpolymers of acrylamide, 2-dimethylammonium ethyl (meth) acrylate, which has been quaternized with methyl chloride (ADAME-Q) and 3-dimethylammonium propyl (meth) acrylamide, which has been quaternized with methyl chloride (DIMAPA-Q).

The polyelectrolytes according to the invention can be prepared by known processes, such as, for example, emulsion, solution, gel and suspension polymerization, preferably gel and solution polymerization. It is essential to the invention, however, that the composition of the polyelectrolytes is characterized by the above-mentioned toxicity index With

Q _T p = total cationic charge of the polymer Q _E = charge fraction of the ester-type monomer.

Such polyelectrolytes are preferably prepared by introducing the combination of the cationic monomers based on (meth) acrylic acid esters and monomers based on (meth) acrylamides and (meth) acrylamide and / or hydrolysis-stable cationic monomers in an aqueous solution and the polymerization initiated. During the polymerization, a solid gel forms from the monomer solution, which is then crushed, dried and ground.

The polyelectrolytes according to the invention are preferably polymerized from the monomers mentioned above in aqueous solution. The solution obtained can be used directly for the production of the products according to the invention.

The polymerization is preferably carried out as an adiabatic polymerization and can be started either with a redox system or with a photoinitiator. A combination of both start variants is also possible. The redox initiator system consists of at least two components - an organic or inorganic oxidizing agent and an organic or inorganic reducing agent. Compounds with peroxide units are frequently used, for example inorganic peroxides such as alkali metal and ammonium persulfate, alkali metal and ammonium perphosphates, hydrogen peroxide and its salts, in particular sodium peroxide, barium peroxide or organic peroxides such as benzoyl peroxide, butyl hydroperoxide or peracids such as peracetic acid. In addition, however, other oxidizing agents can also be used, for example potassium permanganate, sodium and potassium chlorate, potassium dichromate, etc. Sulfur-containing compounds such as sulfites, thiosulfates, sulfinic acid, organic thiols, such as, for example, ethyl mercaptan, 2-hydroxyethanethiol, 2-mercaptoethylammonium chloride and thioglycol can be used as reducing agents and others are used. In addition, ascorbic acid and low-valent metal salts can be used, preferably copper (I), manganese (II) and iron (II) salts. Phosphorus compounds can also be used, for example sodium hypophosphite. In the case of photopolymerization, the reaction is started with UV light, which causes the starter to decay. Benzoin and benzoin derivatives, such as benzoin ether, benzil and its derivatives, such as benzil ketals, acryldiazonium salts, azo initiators such as, for example, 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-amidinopropane) hydrochloride or acetophenone, can be used as starters. derivatives are used. The amount of the oxidizing and reducing components can range between 0.00005 and 0.5 percent by weight, preferably from 0.001 to 0.1 percent by weight based on the monomer solution and for photoinitiators between 0.001 and 0.1 percent by weight, preferably 0.002 to Move 0.05 percent by weight.

The polymerization is carried out batchwise in an aqueous solution in a polymerization vessel or continuously on an endless belt, as described, for example, in DE 35 44 770. This document is hereby introduced as a reference and is considered part of the disclosure. The process is started at a temperature between -20 and 50 ° C, preferably between -10 and 10 ° C, and carried out at atmospheric pressure without the addition of external heat, the heat of polymerization resulting in a maximum final temperature of 50 to dependent on the content of polymerizable substance 150 ° C is obtained.

After the end of the polymerization, the polymer present as a gel is comminuted.

The comminuted gel is then dried discontinuously in a forced-air drying cabinet at 70 to 150 ° C., preferably at 80 to 130 ° C. Drying can be carried out continuously in the same temperature ranges on a belt dryer or in a fluidized bed dryer. After drying, the product is ground to the desired grain size.

The water-soluble terpolymers of acrylamide, 2-dimethylammonium ethyl (meth) acrylate which has been quaternized with methyl chloride (ADAME-Q) and 3-dimethylammonium propyl (meth) acrylamide which has been quaternized with methyl chloride (DIMAPA-Q) are particularly fast according to the invention are very fast and are soluble without residue.

The advantage of this is that solutions of these products, as will be demonstrated in application tests below, are still highly effective even after 72 hours. In comparison, cationic polymers, in particular copolymers based on quaternized methacrylic acid esters, in particular of the ADAME quat type, have a marked loss of activity after 72 hours. In addition, such polymer solutions of the ADAME quat type already show a clear turbidity after 24 hours.

It was also found, completely surprisingly, that the combination of quaternized (meth) acrylamide derivative and a (meth) acrylic acid derivative according to the invention makes it possible to obtain polymers as cationic monomers which lose their toxicity after a short time in solution due to hydrolysis and charge neutralization.

It could be shown that the fish toxicity of the water-soluble polyelectrolytes, in particular terpolymers in solution, which can be obtained by polymerizing the monomers (meth) acrylamide, quaternized (meth) acrylamide derivative and a (meth) acrylic acid derivative and / or hydrolysis-stable cationic monomers, the composition of the polyelectrolytes through the above-mentioned toxicity index F | are markedly reduced from 6.2 mg / l to> 100 mg / l after 72 hours, although the application properties only changed slightly. It was also found that only terpolymers whose composition corresponds to the above equation for the toxicity index Fi have these properties.

In addition, the polyelectrolytes according to the invention have a significantly better dewatering performance than corresponding products of the prior art. As is shown experimentally below, a method according to EP 0 649 820 game 3 produced terpolymer with 22.5 mol% cationic monomer (DIMAPA-Q), 22.5 mol% acrylic acid and 55 mol% acrylamide in the sludge dewatering tests a significantly lower dewatering performance. Thus, despite a 25% higher dosage of the 0.1% solution after 1 hour of standing, the dewatering performance was significantly below that of a cationic terpolymer according to the invention. Even after the solution had stood for 3 days, the drainage performance of the terpolymer according to the invention was above that of the corresponding ADAME-acrylamide copolymer and of the amphoteric polymer according to EP 0649820.

The dissolving time for producing a 0.1% solution of the amphoteric polymer analogous to EP 0 649 820 was approximately 2 hours. A residue of approximately 20 g was found. The fish toxicity (OECD 203) of the product was above 100 mg / l.

Because of these advantageous properties, the polyelectrolytes according to the invention can be used with particular preference for dewatering sewage sludge, for cleaning waste water or treating drinking water or for producing paper or cardboard. In addition, such polyelectrolytes can also be used in water-in-water polymer dispersions, which are also the subject of the present invention.

In the following the invention is explained with the aid of examples. These explanations are only examples and do not limit the general idea of the invention.

Examples

Determination of the solution viscosity of the polymer

The viscosities were determined using a Brookfield viscometer on a 1.0% solution in 10% NaCl solution. The solving time was one hour.

Determination of the gel content of the polymer

To determine the insoluble fraction, 1 l of a 0.1% solution in tap water is added and the mixture is stirred at 300 rpm for 60 min. It is then filtered through a 0.315 mm sieve and rinsed with 5 l of water. The supernatant is transferred to a measuring cylinder and the volume is determined.

The following abbreviations are used:

ABAH: 2,2'-azobis (2-amidinopropane) hydrochloride DIMAPA quat: 3-dimethylammonium propyl (meth) acrylamide, which was quaternized with methyl chloride

ADAME quat: 2-dimethylammonium ethyl (meth) acrylate that has been quaternized with methyl chloride

Versenex 80 The DOW Chem. Comp.

Application methods:

Determination of the drainage effect using the sieve test method

This test method is adapted to the drainage process used in practice, namely continuous pressure filtration using filter presses or centrifugal dewatering in centrifuges.

This method usually tests organic cationic polymers with regard to their suitability for conditioning and dewatering of municipal or industrial sludges.

The sludge is conditioned with the flocculant solution to be tested under constant conditions (depending on the existing dewatering unit). After conditioning, the sludge sample is filtered (= dewatered) on a metal sieve (200 μm mesh size). The duration of the dewatering (t ^) is measured for a given amount of filtrate and the clarity of the draining filtrate in a clarifying wedge (optically).

Clarity: "0" = no clarification

Clarity: "46" = best clarification

Determination of the ionogenicity and the charge density of polymeric flocculants with the PCD device from Mütek

When examining e.g. Development products also require precise knowledge of the existing charge density / ionicity (cationic, anionic, nonionic) of a synthetic flocculant (FHM).

The PCD device (type: 03 pH) from Mütek (D-82211 Herrsching) can be used for both qualitative and quantitative determination. In polyelectrolyte titration, the counterions are compensated for by adding mutually charged polyions until the polymer chains no longer have any external charges. This neutral point corresponds to the isoelectric point or inflection point of the titration.

The polyelectrolyte requirement required for this neutralization then enables, with appropriate knowledge of the underlying polymer base of the product, a calculation of the ionicity.

Polymers According to the Invention:

The polymers according to the invention can be produced by customary polymerization processes. These are preferably produced after the gel polymerization. An example of this is the polymerization, as shown in Example 1:

Example 1 :

Polymer 1

240.0 g of 50% aqueous acrylamide solution were initially placed in a polymerization vessel and mixed with 406.0 g of water and 0.15 g of Versenex 80. After the addition of 350.0 g of 80% ADAME Quat solution, the pH was adjusted to 5.0 with 2.8 g of 50% sulfuric acid, the mixture was cooled to -0 ° C. and blown out with nitrogen. After the addition of 0.40 g of ABAH (2,2'-azobis (2-methylpropionamidine) dihydrochloride), the polymerization was started with UV light. The polymerization runs from -5 ° C to 80 ° C within 25 min. The polymer was ground with a meat grinder and dried at 100 ° C for 90 min. The product was ground to a grain size of 90-1400 μm.

Example 2:

Polymers 2 to 4 and 6 - terpolymers with ADAME-Quat and DIMAPA-Quat

The synthesis was again carried out as described in Example 1, only the cationic monomers and amounts of water were changed as described in the table.

Example 3:

Polymer 5 analogous to EP 0 649 820

240 g of 50% aqueous acrylamide solution were initially placed in a polymerization vessel and mixed with 429.0 g of water and 0.15 g of Versenex 80. After the addition of 233.3 g of 60% DIMAPA quat solution and 52.0 g of acrylic acid, the pH was adjusted to 5.0 with 45 g of 50% sodium hydroxide solution, the mixture was cooled to -0 ° C. and blown out with nitrogen. After the addition of 0.40 g of ABAH (2,2'-azobis (2-methylpropionamidine) dihydrochloride), the polymerization was started with UV light. The polymerization runs from -5 ° C to 80 ° C within 25 min. The polymer was ground with a meat grinder and dried at 100 ° C for 90 min. The product was ground to a grain size of 90-1400 μm.

Example 4:

Polymer 7 - Amphoteric terpolymer with sodium acrylate / DIMAPA quat

160.0 g of 50% aqueous acrylamide solution were initially placed in a polymerization vessel and mixed with 360.0 g of water and 0.15 g of Versenex 80. After the addition of 400.0 g of 60% DIMAPA quat solution and 80.0 g of acrylic acid, the pH was adjusted to 5.0 with 59 g of 50% sodium hydroxide solution, the mixture was cooled to -0.degree Blown out nitrogen. After the addition of 0.40 g of ABAH (2,2'-azobis (2-methylpropionamidine) dihydrochloride), the polymerization was started with UV light. The polymerization runs from -5 ° C to 80 ° C within 25 min. The polymer was ground with a meat grinder and dried at 100 ° C for 90 min. The product was ground to a grain size of 90-1400 μm.

Example 5:

Polymer 8 - Amphoteric terpolymers with sodium acrylate / ADAME quat

The synthesis was carried out as in Example 4, except that 300.0 g of ADAME quat (80% strength solution) and 390.0 g of water were used instead of DIMAPA quat.

Example 6:

Polymer 9

The polymerization was carried out as in Example 1, except that 275.0 g of ADAME quat, 360.0 g of acrylamide and 365.0 g of water were weighed out.

Example 7:

Polymer 10

334.4 g of 50% aqueous acrylamide solution were initially placed in a polymerization vessel and mixed with 296.5 g of water and 210 mg of Versenex 80. After 354.6 g of 60% DIMAPA-Quat solution had been added, the pH was adjusted to 5.0 with 8.0 g of 50% strength sulfuric acid and 0.30 g of formic acid, the mixture was cooled to -5 ° C. and blown out with nitrogen , After the addition of 0.40 g of ABAH (2,2'-azobis (2-methylpropionamidine) dihydrochloride), the polymerization was started with UV light. The polymerization runs from -5 ° C to 80 ° C within 25 min. The polymer was minced in a meat grinder and dried at 100 ° C for 90 min. The product was ground to a grain size of 90-1400 μm.

Example 8:

Polymer 11

The polymerization was carried out as described in Example 7, except that 240 g of acrylamide solution, 285.3 g of water and 466.7 g of DIMAPA quat were used. In addition, the polymerization was started at 7.5 ° C.

Example 9:

Polymer 12

The polymerization was carried out as in Example 8, except that it was started at 0 ° C. in order to obtain a higher viscosity.

Example 10:

Polymers 13 and 14

Example 11:

Polymer 15

The synthesis was again carried out as described in Example 6, but was started at 5 ° C.

Properties of the polymers

Example 12:

Polymers for dewatering a fiber suspension

Polymer 16

416.0 g of 50% aqueous acrylamide solution were initially placed in a polymerization vessel and mixed with 435.0 g of water and 0.15 g of Versenex 80. After the addition of 140.0 g of 80% ADAME Quat solution, the pH was adjusted to 5.0 with 0.1 g of 50% sulfuric acid, the mixture was cooled to 0 ° C. and blown out with nitrogen. After the addition of 0.40 g of ABAH (2,2'-azobis (2-methylpropionamidine) dihydrochloride), the polymerization was started with UV light. The polymerization runs from -5 ° C to 80 ° C within 25 min. The polymer was ground with a meat grinder and dried at 100 ° C for 90 min. The product was ground to a grain size of 90-1400 μm.

Polymers 17 to 20

These polymers were produced as in polymer 16, only with the modified weights indicated in the table below:

All polymers have a total cationic charge of 35 mass percent:

^* Shares in percent by mass

The polymers 18 to 20 are polymers according to the invention, while the polymers 16 and 17 are comparative examples.

Application tests

Hydrolysis tests: course of the cation activity as a function of time (pH: 9, RT)

Measured with Mütek PCD Dewatering of municipal sewage sludge using the sieve test method

Loss on ignition: 50.5%

Dry matter of the sludge (TS): 31 kg / m ³

El. Conductivity: 8.3 mS / cm ³

Fish toxicity of polymers (OECD 203) after 72 h at RT

no hydrolysis Dewatering of municipal sewage sludge using the sieve test method

1): Loss on ignition: 57.3% dry matter of the sludge (TS): 30 kg / m ³ ; El. Conductivity: 6.3 mS / cm ³

2): Loss on ignition: 55.9% dry matter of the sludge (TS): 26 kg / m ³ ; El. Conductivity: 6.4 mS / cm ³

Drainage of a fiber suspension

In these experiments, the polymers according to the invention were tested as retention aids for papermaking. This test works according to the recognized "Dynamic Drainage Jar" method. The fiber suspension is dewatered on a sieve with constant stirring - without building up a filter layer. The total and filler retention can be calculated by determining the solids content in the fiber sample and the filtrate This examination was carried out with a Mütek DFS 03. In each of the examples, 1 L of a 1% fiber suspension was dewatered. The table shows the mass of water released.

As can be seen from the table, comparable results were obtained for all products within the scope of the measurement accuracy in the drainage tests. Here, however, the polymers according to the invention have a significantly more favorable toxicity than the other products.

Drainage on a chamber filter press

An 80% by weight cationic terpolymer (20% by weight of acrylamide, 40% by weight of ADAME quat and 40% by weight of DIMAPA quat) with a viscosity of 300 mPas was used in a sewage treatment plant Combination Zetag® 7848 FS 40 (trade name of an emulsion polymer from Ciba Specialty Chemicals AG) and Zetag 7587 (80% by weight Adame-Quat and 20% by weight acrylamide) tested. 7 kg of terpolymer according to the invention per ton of solid were required for dewatering on a chamber filter press, while 8 kg of polymer were required for the combination (emulsion converted to polymer).

The dry matter content in the pressed sludge was the same.

Claims

claims

Claim 1: Polyelectrolytes obtainable by polymerizing the monomers of (meth) acrylamide, a quaternized (meth) acrylamide derivative, a (meth) acrylic acid derivative and / or hydrolysis-stable cationic monomers, the composition of the polyelectrolytes being characterized by a toxicity index

F, = (Q _TP - 2Q _ME ) / 10 <1 with

Q _T p = total cationic charge of the polymer

Q _ME = charge fraction of the ester-type monomer.

Claim 2:

Polyelectrolytes according to claim 1, characterized in that they have a total charge of 1 to 99 mol%.

Claim 3:

Polyelectrolytes according to claims 1 to 2, characterized in that the terpolymers have a solution viscosity of 10 to 2000 mPas.

Claim 4: Polyelectrolytes according to Claims 1 to 3, characterized in that the quaternized acrylamide derivative is 3-dimethylammonium propyl (meth) acrylamide, which is quaternized with methyl chloride (DIMAPA quat).

Claim 5: Polyelectrolytes according to Claims 1 to 4, characterized in that the quaternized acrylic acid derivative is 2-dimethylammonium ethyl (meth) acrylate, which has been quaternized with methyl chloride (ADAME quat). Claim 6:

Polyelectrolytes according to claims 1 to 5, characterized in that the terpolymers contain 0.1 to 20% of a high cationic, low molecular weight polyelectolyte.

Claim 7:

Polyelectrolytes according to Claims 1 to 6, characterized in that they are terpolymers which can be obtained by polymerizing the monomers of (meth) acrylamide, a quaternized (meth) acrylamide derivative and a (meth) acrylic acid derivative, and / or hydrolysis-stable cationic monomers.

Claim 8: polyelectrolytes according to Claims 1 to 7, characterized in that the production of the polymers is carried out by the gel polymerization process.

Claim 9:

Polyelectrolytes according to Claims 1 to 7, characterized in that the preparation of the polymers is carried out by the emulsion polymerization process.

Claim 10:

Polyelectrolytes according to Claims 1 to 7, characterized in that the polymers are prepared by the suspension polymerization process.

Claim 11:

Use of the polyelectrolytes according to claims 1 to 10 for dewatering

sewage sludge

Claim 12:

Use of the polyelectrolytes according to claims 1 to 10 for the purification of waste water or treatment of drinking water. Claim 13:

Use of the polyelectrolytes according to claims 1 to 10 for the production of

Paper or cardboard.

Claim 14:

Water-in-water polymer dispersions characterized in that they contain polyelectrolytes according to claims 1 to 10.