WO1997011144A1

WO1997011144A1 - Use of polycarboxylic acid half-amides as additive to washing and cleaning agents

Info

Publication number: WO1997011144A1
Application number: PCT/EP1996/004001
Authority: WO
Inventors: Richard Baur; Norbert Greif; Axel Kistenmacher; Knut Oppenländer
Original assignee: Basf Aktiengesellschaft
Priority date: 1995-09-20
Filing date: 1996-09-12
Publication date: 1997-03-27
Also published as: DE19534847A1

Abstract

The invention concerns the use of polycarboxylic acid half-amides obtained by reacting (a) polymers containing anhydride groups and having an average molecular mass Mw of between 200 and 100 000, and (b) aminocarboxylic acids comprising a primary or secondary amino group, taurine, C1-C18 alkyltaurines and/or aminophosphonic acid, as an encrustation-inhibiting additive to phosphate-free and phosphate-reduced washing and cleaning agents.

Description

Use of polycarboxylic acid halamides as an additive to detergents and cleaning agents

description

The invention relates to the use of polycarboxylic acid halamides which can be obtained by reacting anhydride group-containing polymers and compounds containing amino groups as an additive to detergents and cleaning agents.

From US-A-4 702 858 i.a. the use of polycarboxylic acid half amides is known as a graying-inhibiting additive to detergents which primarily requires washing action. According to one embodiment, copolymers with a molecular weight (weight average) of 5,000 to 500,000 are produced by radical copolymerization of acrylic acid and maleic anhydride in xylene. The copolymers are then converted to polycarboxylic acid halamides by reaction with amines such as tridecylamine or stearylamm.

From US-A-4 018 702 the use of reaction products of polymalic anhydride and iminodiacetate as a scale inhibitor is known.

The preparation of polymalic anhydride by radical polymerization of maleic anhydride in inert solvents is known, cf. GB-A-1 024 725, GB-A-1 411 063 and US-A-3 810 834. According to the process known from US-A-4 818 795, maleic anhydride is converted into aromatic hydrocarbons at temperatures of 60 up to 200 ° C. in the presence of 1 to 20% by weight, based on maleic anhydride, polymerized on peroxyesters. Polymalemic anhydrides with a low residual monomer content are obtained.

Processes for the preparation of copolymers containing maleic anhydride units are known from EP-A-0 264 627 and EP-B-0 276 464. The copolymerization takes place in the presence of peroxyesters as a catalyst in aromatic hydrocarbons, for example toluene, xylene, ethylbenzene and isopropylbenzene. Examples of comonomers which can be used are vinyl esters of saturated C 1 -C ₄ -carboxylic acids, ethylenically unsaturated C ₃ -C ₅ -carboxylic acids and compounds containing at least two monoethylenically unsaturated double bonds. The polymers containing maleic anhydride units, which are prepared by free radical polymerization in aromatic solvents, contain considerable amounts of solvents in bound form. EP-B-0 009 171 discloses the preparation of polymalic anhydride by polymerizing maleic anhydride in acetic anhydride with hydrogen peroxide as a catalyst.

The object of the present invention is to provide additives for use in detergents which are more effective than the polymers previously used for the incrustation-inhibiting action and the primary washing action.

The object is achieved according to the invention with the use of polycarboxylic acid halamides, which are obtained by reacting

(a) Polymers containing anhydride groups and having an average molecular weight M _{w of} from 200 to 100,000 and

(b) Aminocarboxylic acids which have a primary or secondary amino group, Taunn, C _x - to Ciβ "alkyltaurines and / or aminophosphonic acids

available smd, as an additive to detergents.

Containing anhydride groups as polymers with an average molecular weight M _w from 200 to 100,000 come polymers of Maiein ^* saureanhydrids into consideration, which are known for the most part from the above-given an¬ prior art. They are produced with particular advantage by polymerizing maleic anhydride, optionally in the presence of comonomers, in inert solvents in the presence of peroxyesters. Such processes are described, for example, in US-A-4,818,795, EP-A-0 264 627 and

EP-B-0 276 464. The polymerization is usually carried out at from 60 to 200 ° C. in the presence of 1 to 20% by weight, based on the monomers, of a peroxyester. The polymerization can be, for example, m benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, diisopropylbenzene,

Tetraalkylbenzenes, naphthalene, methyl indole, dodecyl benzene and mixtures of the aromatic solvents mentioned are carried out. In the radical polymerization of maleic anhydride, toluene, xylene, ethylbenzene, isopropylbenzene or mixtures thereof are preferably used as solvents. Both the homopolymers of maleic anhydride and the copolymers with other monomers can be used as component (a).

As comonomers, for example, come C ₂ - to Cι ₂ -01efme, preferably ^¬, C ₂ - to Ca and particularly preferably C ₂ - to C ₄ -α-01efme into consideration, for example ethylene, propylene, butene-1, isobutene, and Duso- buten. These copolymers are mainly alternating polymers, ie they contain maleic anhydride and the comonomer in a molar ratio of 1: 1. Also suitable as comonomers are styrene, C 1 -C ₄ -alkyl methyl ether, vinyl esters of saturated C 1 -C ₄ -monocarboxylic acids, acrylic acid, methacrylic acid or mixtures of the comonomers mentioned. Of the alkyl vinyl ethers, preference is given to methyl vinyl ether and ethyl vinyl ether. Preferred vinyl esters are vinyl acetate and methyl formate.

Also of interest are copolymers of maleic anhydride with 0.1 to 10% by weight, based on maleic anhydride, of at least one crosslinking agent containing two ethylenically unsaturated double bonds. Such crosslinkers include, for example, glycol diacrylates and glycol dimethacrylates such as butanediol diacrylate or the diacrylates and dimethacrylates of polyalkylene glycols, e.g. of polyethylene glycol with molar masses from 100 to 10,000. Other suitable crosslinking agents are, for example, butanediol divinyl ether, pentaerythritol triallyl ether, triallylsucrose and pentaallylsaccharose. If they are present during the polymerization, the crosslinking agents are preferably used in an amount of 0.2 to 5% by weight, based on maleic anhydride.

Particular preference is given to using component (a) polymaleic anhydrides which can be obtained by radical polymerization of maleic anhydride, optionally in the presence of copolymerizable comonomers in toluene, xylene, ethylbenzene or mixtures thereof, and which have an average molecular weight M _w of 300 have up to 3,000. Preferred copolymerizable comonomers are isobutene, diisobutene, ethylene and acrylic acid. The molar mass of the polymers containing anhyride groups is preferably 300 to 3,000. If the polymerization of the maleic anhydride is carried out with an aromatic solvent, up to 50% by weight, preferably up to 40% by weight, of the polymer can consist of chemically bound solvents which the polymers have been produced smd.

In the case of copolymers of maleic anhydride, the content of comonomers in the copolymer is, for example, 10 to 90, preferably 30 to 70 mol%.

The above-described polymers containing anhydride groups are reacted with aminocarboxylic acids which have a primary or secondary amino group, taurine, C 1 -C to CIB alkyl tauπnen and / or aminophosphonic acid. One can therefor acids, all amino or using mixtures of amino acids that eme pri ^¬ mare or secondary amino group include, for example Glyzm, alanine, ß-alanine, valine, leucine, methionm, cysteine, ammocaproic acid, caprolactam, asparagine, isoasparagm, glutamm, isoglutamm, aminodicarboxylic acids such as aspartic acid and glutamic acid, cysteine, N-methylamino acids such as N-methylglycine (sarcosine), as well as sarcosine, as well as Serine, threonm, proline, iminodiacetic acid and basic diaminocarboxylic acids such as lysine, lysm hydrochloride, arginine, histidine and α-aminocaprolactam. Amino carboxylic acids and sarcosine, aspartic acid, asparagine, alanine, glycine and mixtures of the compounds mentioned are preferably used. The implementation products of

(a) Polymalemic acid anhydrides, which are obtainable by radical polymerization of malic acid anhydride, optionally in the presence of comonomers copolymerizable therewith in toluene, xylene, ethylbenzene or mixtures thereof, and have an average molar mass M _w of 300 to 3000 and

(b) sarcosine, aspartic acid or mixtures thereof.

As ammosulfonic acids come, for example, taurine, Ci bis

Ci8 alkyl radicals such as methyl taurine, sulfanilic acid or other aromatic ammosulfonic acids. Suitable ammophosphonic acids, for example propylammomethylenephosphonic acid, generally alkylaminoalkylenephosphonic acids.

In the reaction of the polymers of group (a) containing anhydride groups with the compounds of group (b), when the reaction is complete, a carbonic acid halamide group is formed from an anhydride group. However, the reaction can also be carried out only partially, so that only a small part of the anhydride groups present in the copolymer is converted into half-amide groups, e.g. 70%. The remaining part of the anhydride groups of the polymer is then converted into dicarboxylic acid groups during the reaction. In the reaction of compounds (a) and (b), for example, the anhydride groups-containing polymers (a) are reacted in such a ratio with at least one compound of group (b) that 0 per mole of anhydride groups in the polymer (a) , 1 to 2, preferably 0.2 to 1 mol of the compounds (b) containing amino groups are used.

The reaction is preferably carried out in an aqueous medium. Advantageously, an aqueous solution of an alkali metal salt, preferably a sodium or potassium salt, of at least one compound (b) is initially introduced, and the polymeric compound (a) containing anhydride groups is added all at once, continuously or batchwise. The reaction is carried out, for example, in the temperature range from 30 to 100, preferably 50 to 80 leads. The pH of the reaction solution is, for example, 6 to 12. The reaction of the compounds (a) and (b) proceeds within about 30 minutes to 5 hours, with higher reaction temperatures leading to shorter residence times. The reaction can also be carried out at temperatures above 100 ° C., provided that the reaction is carried out under pressure in specially equipped apparatus. The sodium salt of an aminocarboxylic acid is usually initially introduced as a 40 to 50% strength aqueous solution, heated to a temperature of 70 to 80 ° C. and the polymers containing anhydride groups are added in portions. However, the reaction can also be carried out in tertiary amines such as tripropylamine or pyridine as solvents. When reacting iminodiacetic acid with a compound of group (a), it has proven advantageous to use tripropylamine or pyridine. After the reaction has ended, the amine is distilled off and the reaction product is isolated in the form of the sodium salt. The resulting polycarboxylic acid halamides can be characterized using IR spectra and using the KOH titer. The polycarboxylic acid halamides have, for example, molecular weights of 400 to 4500, preferably 500 to 2500.

The polycarboxylic acid halamides described above are usually used in washing and cleaning agents in an amount of 0.01 to 20, preferably 0.05 to 15,% by weight, based on the total weight of the respective formulation. The detergent formulations are predominantly phosphate-free or reduced phosphate detergents. Reduced phosphate detergents are understood to mean those formulations which contain at most 25, preferably at most 10% by weight of phosphate, calculated as pentasodium triphosphate.

The composition of washing and cleaning formulations can be very different. Detergents and cleaning agents usually contain 2 to 50% by weight of surfactants and optionally builders. This information applies to both liquid and powder detergents. Examples of the composition of detergent formulations which are common in Europe, the USA and Japan can be found, for example, in Chemical and Engn. News, Vol. 67, 35 (1989) tabulated. Further information on the composition of detergents and cleaning agents can be found in Ullmann's Encyclopedia of Technical Chemistry, Verlag Chemie, Weinheim 1983, 4th edition, pages 63-160. Detergent formulations can contain up to 60% by weight of an alkali silicate and up to 20% by weight of a detergent polymer. Suitable alkali metal silicates at ^¬ play, the amorphous sodium disilicates, which are described in EP-A 0,444,415 and DE-A 40 04 626, as well as crystalline layered silicates, which contain detergent formulations as builders according to EP-A 0 337 219 m and are used for softening water according to EP-B 0 164 514, and sodium silicates, which are dewatered from sodium silicate solutions and dried to water contents from 15 to 23, preferably 18 to 20% by weight available smd.

If necessary, detergents can also contain a bleaching agent, e.g. Sodium perborate which, if used, can contain up to 30% by weight in the detergent formulation. The detergents and cleaning agents can optionally contain other conventional additives, e.g. Complexing agents, citrates, opacifiers, optical brighteners, enzymes, perfumes, color transfer inhibitors, graying inhibitors and / or bleach activators.

Detergent and cleaning agent formulations, each containing 0.01 to 20, preferably 0.05 to 15% by weight, based on the total weight, of the compounds to be used according to the invention, apart from surfactants, can contain 15 to 50% by weight as additional constituents Builders and optionally co-builders, 5 to 35% by weight of bleach and optionally bleach activators, 3 to 30% by weight of auxiliaries such as enzymes, foam regulators, corrosion inhibitors, optical brighteners, fragrances, dyes or formulation auxiliaries, such as eg contain sodium sulfate. The detergents and cleaning agents can be in solid form, for example in the form of powder or granules, or in liquid form. For the so-called color detergents, the content of color transfer inhibitors and / or graying inhibitors in amounts of 0.05 to 5% by weight, preferably 0.2 to 2.5% by weight, is becoming increasingly important. Suitable color transfer inhibitors are, for example, water-soluble polymers such as polyvinylpyrrolidone, polyvinylimidazole, copolymers of vinylimidazole and vinylpyrrolidone and polyvinylpyrrolidone-N-oxide. Copolymers of Vmylimidazol and Vmylpyrrolidon are described for example in WO-A-94/26796 as a color transfer inhibitor. In addition, finely divided, crosslinked copolymers of Vmylimidazol and Vmyl ^¬ pyrrolidone with particle sizes of approx. 1 μm to 500, preferably 5 to 200 μm, are suitable as color transfer inhibitors.

Suitable graying inhibitors are known for example from US-A-4 746 456, GB-A-1 154 730 and DE-A-4 403 866. Further information on surfactants, bleaching agents and bleach activators in detergent formulations can be found in WO-A-94/24096 and WO-A-95/0585. Cleaners for hard surfaces include, for example, cleaners for cleaning metal, plastics, glass and ceramics, floor cleaners, sanitary cleaners, all-purpose cleaners in the household and in commercial applications, technical cleaners (for use in car washes or high-pressure cleaners), cold cleaners, dishwashers , Rinse aids, disinfectant cleaners, cleaners for the food and beverage industry, in particular as bottle cleaners, as CIP cleaners (cleaning-in-place) in dairies, breweries and other businesses of food manufacturers. Cleaners which contain the polymer mixtures according to the invention are particularly suitable for cleaning hard surfaces such as glass, plastic and metal. The cleaners can be alkaline, acidic or neutral. They usually contain tensides in amounts of about 0.2 to 50% by weight. These can be anionic, nonionic or cationic surfactants and mixtures of surfactants which are compatible with one another, for example mixtures of anionic and nonionic or of cationic and nonionic surfactants. Alkaline cleaners can contain soda, potash, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium sesquicarbonate, potassium sesquicarbonate, sodium hydroxide, potassium hydroxide, amine bases such as monoethanolamine, diethanolamine, triethanolamine, ammonia or silicate in amounts of up to 60% by weight, in some cases even up to 80% by weight. %. The cleaners can also contain citrates, gluconates or tartrates in amounts up to

Contain 80 wt .-%. They can be in solid or liquid form.

The polycarboxylic acid halamides to be used according to the invention can be referred to as co-builders. They bring about a significant reduction in the incrustation when washing textiles. They can also be called incrustation inhibitors.

In the examples, the parts mean parts by weight and the information in percent by weight, unless otherwise indicated.

Examples

Production of the polycarboxylic acid half-amides to be used according to the invention

Adduct 1:

278 parts of a 40% aqueous solution of the sodium salt of sarcosine are heated to a temperature of 70 ° C. and mixed at this temperature with 173 parts of oligomaleic anhydride with an average molecular weight M _w of 600, heated to 80 ° C. and for 1 hour stirred at 80 ° C. A homogeneous emulsion is obtained which can be would be diluted by water to a solids content of 50%. The acid number of the adduct is 1.455 meq KOH / g.

The oligomaleic anhydride was prepared according to Example 1 of 5 US-A-4 818 795 by polymerizing maleic anhydride in xylene. 0.7 mol of sarcosine Na salt was used per mole of anhydride groups in the polymer.

Adduct 2:

10 A mixture of 43 parts of β-alanine and 30 parts of water are mixed with 38.4 parts of 50% aqueous sodium hydroxide solution. The solution thus obtained is heated to a temperature of 70 ° C. Once this temperature is reached, 116 parts of a 61% solution of polymalic anhydride in ethylbenzene are added within

15 to 30 min. The reaction mixture is heated to 80 ° C. and stirred at this temperature for 1 hour. A mixture of water and ethylbenzene is then distilled off under reduced pressure (70 mbar), the temperature of the reaction mixture being 70 ° C. The solvent-free aqueous solution thus obtained becomes

20 adjusted to a solids content of 50% by adding water. The acid number is 1.230 meq KOH / g.

The polymalemic anhydride used had an average molecular weight M _w of 580. It was prepared as described in Example 7 of US Pat. No. 4,818,795.

Adduct 3:

A mixture of 54 parts of ethanolaminoacetic acid and 37 parts

Water is mixed with 36 parts of 50% aqueous sodium hydroxide solution.

30 sets. The solution is heated to a temperature of 70 ° C. As soon as this temperature is reached, 109 parts of the 61% strength polymaleic anhydride solution in ethylbenzene described above under adduct 2 are added within 25 min and the reaction mixture is stirred at a temperature of 80 ° C. for 1 hour. Subsequently

A mixture of ethylbenzene and water is distilled off until a solvent-free aqueous solution is obtained, which is diluted to a solids content of 50% by adding water. The acid number of the adduct is 1.125 meq KOH / g.

40 adduct 4:

40 parts of aspartic acid and 18 parts of water are mixed with 48 parts of 50% aqueous sodium hydroxide solution. The aqueous solution of the sodium aspartate is heated to 70 ° C. and at this temperature within 30 min with 73 parts of the adduct 2 described above.

45 written 61% solution of polymalic anhydride in ethyl benzene added. The reaction mixture is stirred at 80 ° C. for 1 hour and then under reduced pressure of ethylbenzene freed and adjusted to a solids content of 50% by adding water. The adduct has an acid number of 1.203 meq KOH / g. 1 mol of Na aspartate was used per mol of anhydride groups in the polymer. 5

Adduct 5:

53 parts of pyridine are placed in a stirred flask and 66.5 parts of iminodiacetic acid are added with stirring and the mixture is heated to a temperature of 70.degree. At this temperature you add

10 49 parts of the polymaleic anhydride described in the preparation of adduct 1 and heats the reaction mixture to a temperature of 130.degree. 400 parts of water and 120 parts of 50% strength aqueous sodium hydroxide solution are then added and the volatile constituents are removed to a temperature of up to 30 mbar

15 60 ° C. A sample of the dry reaction product is examined by IR spectroscopy. The anhydride band at 1780 cm " ¹ is no longer recognizable, but an amide band at 1630 cm ^{" 1 has} arisen. 1 mol of iminodiacetic acid Na salt was used per mole of anhydride groups in the polymer.

20th

Adduct 6:

89 parts of an alternating copolymer of isobutene and maleic anhydride with an average molecular weight M _w of 4000 are added to an aqueous sodium sarcosinate solution which is obtained by

25 mixing of 58 parts of sarcosine, 52 parts of 50% aqueous sodium hydroxide solution and 35 parts of water was obtained. The reaction mixture is stirred for 3 hours at a temperature of 80 ° C., then enough water is added that a 50% aqueous solution is formed. Per mole of anhydride groups in the copolymer

30 1 mole of sodium sarcosinate.

Adduct 7:

48 parts of the copolymer described under adduct 6

Isobutene and maleic anhydride are described as under adduct 6

35 rubbed with 42 parts of sarcosine, 20 parts of 50% aqueous sodium hydroxide solution and 27 parts of water. The molar ratio of anhydride groups in the copolymer to sodium sarcosinate was 1: 0.7. A 50% aqueous solution is prepared by adding water. A total of 150 parts are obtained.

40

Adduct 8:

The procedure is as described for the preparation of adduct 6, but 58 parts of the copolymer of isobutene and maleic anhydride given there, 11.2 parts sarcosine, 13.6 parts are used

45 water, 10 parts of 50% aqueous sodium hydroxide solution. By adding 27 parts of water, the reaction mixture is concentrated to a solid set at 50%. The molar ratio of anhydride units in the copolymer to sodium sarcosinate was 1: 0.3.

Adduct 9: 48 parts of the copolymer of isobutene and maleic anhydride described under adduct 6 are added to a solution heated to 70 ° C. to 51.5 parts of a 50% strength aqueous solution of tartar sodium salt and 3 hours at 80 ° C stirred. A solids concentration of 50% is set by adding water. The molar ratio of anhydride groups in the copolymer to taurine is 1: 0.5.

Adduct 10:

The procedure is as for the production of adduct 9, but using 44 parts of the alternating copolymer of isobutene and maleic anhydride, 66 parts of 50% aqueous taurine sodium salt solution and 44 parts of water. 154 parts of a 50% strength aqueous solution of the adduct are obtained, in which the molar ratio of anhydride groups to taurine is 1: 0.7.

Adduct 11:

The procedure is as described for the preparation of adduct 9, but using 34.3 parts of the alternating copolymer of isobutene and maleic anhydride and 73.5 parts of 50% aqueous taurine sodium salt solution. 142 parts of a 50% strength aqueous solution of the adduct are obtained, in which the molar ratio of the anhydride groups to taurine is 1: 1.

Some of the adducts described above were tested for their incrustation-inhibiting action in the formulation referred to below as detergent A.

Composition of detergent A:

6.0 parts by weight of sodium dodecylbenzenesulfonate

2.0 parts by weight of C ₆ / C ₈ alkyl sulfate

1.0 part by weight of soap

7.0 parts by weight of the addition product of 7 moles of ethylene oxide and 1 mole of C ₃ / C ₁₅ -oxoalcohol 3.5 parts by weight of sodium metasilicate 5.5 H ₂ 0

36.0 parts by weight of zeolite A

12.0 parts by weight of anhydrous sodium carbonate

15.0 parts by weight of sodium perborate monohydrate

3.5 parts by weight of tetraacetylethylenediamine 1.5 parts by weight of sodium carboxymethyl cellulose

3.0 parts by weight of sodium sulfate

4.5 parts by weight of water 5.0 parts by weight of polymer to be used according to the invention or, in the case of the comparative examples, polymer according to the prior art

Test fabrics made of cotton were washed with detergent formulation A. After the washing process, the ash content of the fabrics was determined by ashing 5 g of the test fabric at 700 ° C. for 2 hours.

The activity (W) of the detergent additive in formulation A is given in percent activity, where 0% activity is the ash content without incrustation inhibitor, i.e. without detergent additive (A-none) and 100% effect corresponds to the ash content of the fabric before washing (A-zero).

The effect W of the additive is calculated from the ascertained ash content (A additive) using the following approach:

(A additive) (A zero)

W = x 100 [%]

(A-none) (A-zero)

The following washing conditions were chosen:

Device: Launder-O-meter from Atlas

Number of washing cycles: 15 washing liquor: 250 g water hardness: 4 mmol per liter (Ca: Mg = 4: 1) washing time: 30 min at 60 ° C (including heating up time)

Fleet ratio: 1: 12.5 Test fabric: Cotton nettle fabric Detergent concentration: 4.5 g / 1

Ash zero value: 0.04% by weight EMPA 211 0.09% by weight Swiss Federal Material BW 221 0.17% by weight testing institute

St. Gallen, Switzerland

The results obtained are given in the following table. o se

io

1) The polymer according to Comparative Example 2 is the preliminary product of adduct 1 hydrolyzed and neutralized with sodium hydroxide solution,

2) the polymer according to Comparative Example 3 is the preliminary product of adduct 6 hydrolyzed and neutralized with sodium hydroxide solution. The preliminary product is to be understood as meaning the polymers containing copolymerized maleic anhydride. o H -fl * ^* **.

Claims

claims

1. Use of Polycarbonsaurehalbamiden by the implementation of

(a) Anhydride group-containing polymers having an average molecular weight M _w of 200 to 100,000 and

(b) Aminocarboxylic acids which have a primary or secondary ammo group, taurine, C _% - to Cis-alkyl taurine and / or aminophosphonic acids

are available as an additive to phosphate-free and phosphate-reduced washing and cleaning agents.

2. Use according to claim 1, characterized in that the anhydride group-containing polymers (a) are obtainable by radical polymerization of maleic anhydride and optionally monomers copolymerizable therewith in an aromatic solvent.

3. Use according to claim 1, characterized in that the anhydride group-containing polymers are obtainable by radical polymerization of maleic anhydride in toluene, xylene, ethylbenzene, isopropylbenzene or mixtures thereof.

4. Use according to claim 1, characterized in that the anhydride group-containing polymers (a) are obtainable by radical polymerization of maleic anhydride and C ₂ - to -C ₂ -01efins.

5. Use according to claim 1, characterized in that the anhydride group-containing polymers (a) by radical polymerization of maleic anhydride with C ₂ - to Cι ₂ -01efinen, styrene, Ci to C ₄ alkyl vinyl ethers, vinyl esters of saturated Ci to C ₄ monocarboxylic acids, acrylic acid, methacrylic acid or mixtures of the comonomers are obtainable.

6. Use according to claim 1, characterized in that sarcosine, aspartic acid, asparagine, alanine, glycine, taurine, methyl taurine or mixtures thereof are used as (b).

7. Use according to any one of claims 1 to 6, characterized labeled in ^¬ characterized in that Polymeri¬ containing anhydride groups sate (a) m a ratio with at least one Reacts compound of group (b) that 0.1 to 2 mol of the compounds (b) having amino groups are used per mole of anhydride groups in the polymer (a).

8. Use according to claim 1, characterized in that the reaction products of

(a) polymaleic anhydrides which, if appropriate in the presence of comonomers copolymerizable therewith, by radical polymerization of maleic anhydride, in

Toluene, xylene, ethylbenzene or mixtures thereof are available and have an average molecular weight M _w of 300 to 3000, and

(b) sarcosine, aspartic acid or mixtures thereof

starts.