EP1084224A1

EP1084224A1 - Aqueous bleaching agent with viscose structure

Info

Publication number: EP1084224A1
Application number: EP99926391A
Authority: EP
Inventors: Hans-Jürgen Riebe; Theodor Völkel; Florence Lambert; Josef Penninger
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1998-06-03
Filing date: 1999-05-25
Publication date: 2001-03-21
Anticipated expiration: 2019-05-25
Also published as: ATE231543T1; WO1999063042A1; DE59904101D1; ES2191434T3; DE19824708A1; EP1084224B1

Abstract

The invention aims at solving the problem of hydrogen peroxide wastage when the agent is poured on dirty textiles and the increased oxidative load on the textile when pretreatment agents containing peroxide are used in an aqueous bleaching agent serving as laundry pretreatment agent. This is substantially achieved by an agent containing 0.2 to 25 % by weight of hydrogen peroxide, complexing agents for heavy metals in a quantity of up to 5 % by weight, surfactants in a quantity of up to 15 % by weight, free-radical scavengers in a quantity of up to 0.1 % by weight and water in quantities ranging from 55 to 90 % by weight and a polysaccharide thickening active substance in quantities such that the substance has a viscosity in the range of from 200 mPa.s to 5,000 mPa.s at 20 DEG C and at rpm 20 (Brookfield rotational viscometer) and a viscosity at rpm 5 (Brookfield rotational viscometer) that is at least 1.5 higher than at rpm 50.

Description

Structurally viscous aqueous bleach

The present invention relates to an aqueous bleaching agent based on hydrogen peroxide, which is particularly suitable for use as a laundry pretreatment agent, but also as an additive in customary washing processes, its use as a laundry pretreatment agent and a washing process using such an agent.

In order to remove stubborn stains, so-called stains, from textiles, they are often treated with special pre-treatment agents before the actual washing process. As far as the problem of removing bleachable stains is concerned, peroxide-containing pretreatment agents are generally used. Because of the then eased application conditions, such pretreatment agents are normally liquid and are poured onto the stain directly or, if appropriate, after dilution with water. Through intensive and longer exposure time of the peroxide-containing agent, an improved removal of the bleachable stains from the textile is achieved if the textile is then subjected to a household washing process, which, in addition to machine washing processes, can also be used by hand washing.

Usual liquid peroxide-containing pretreatment agents are relatively low-viscosity, which means that they generally have viscosities not exceeding 200 mPa.s. In addition to the peroxide, they usually contain water and surfactants, which are said to improve the wettability of the stains when the agent is applied. The high wetting effect and the low viscosity of the agent cause the product to run strongly on the treated textile, so that even if the agent is applied carefully, a much larger area is usually wetted than the actual stain. This means that part of the peroxide applied to the textile is not available for bleaching the soiling, but is wasted, so to speak, because it is not in appropriate direct contact with the stain. A further problem arises when the aqueous pretreatment agent dries on the textile in that the evaporation of the water takes place increasingly at the edges of the liquid, which leads to concentration gradients of the liquid constituents in the sense of a chromatography effect. This results in a concentration of liquid constituents in the edge zone of the liquid. Substances originating from the textile surface, such as heavy metal ions, also migrate to the edge of the wetted surface and occur there in a relatively high concentration. This leads to increased heavy metal-catalyzed hydrogen peroxide decomposition in the edge area of the wetted surface and thus to an increased oxidative load on the textile fibers in this area, which can result in permanent changes in the color impression or even damage to the textile.

In international patent application WO 96/26999 it is proposed to counteract this problem by using chelating agents for iron, copper or manganese, whereas in European patent application EP 0 751 214 the use of certain polyamines is recommended in order to avoid damage to the dyeing and / or fibers becomes. Both do not lead to a completely satisfactory solution in all cases.

Surprisingly, it has now been found that both the problem of wasting hydrogen peroxide and that of the increased oxidative load on the textile can be solved by using peroxide-containing pretreatment agents which have been adjusted to an increased viscosity with the aid of a special thickening agent and have a certain structural viscosity , ie have a ^{non-Newtonian} flow behavior.

Structural viscosity is understood here to mean the effect that the liquid agent has a higher viscosity when exposed to low shear forces than when exposed to higher shear forces. Usually the change in viscosity is not directly proportional to the change in the shear forces, but the viscosity increases with shear forces. decreases in the low shear range more than in those in the high shear range. This property can be checked experimentally by measuring the viscosity under different shear conditions. One way of doing this is to use a conventional rotary viscometer at different speeds of rotation of the spindle.

The invention relates to a liquid water-containing bleaching or laundry pretreatment composition containing 0.2% by weight to 25% by weight of hydrogen peroxide, complexing agents for heavy metals in an amount of up to 5% by weight, surfactant in an amount of up to 15% by weight .-%, radical scavengers in an amount up to 0.1 wt .-% and water in amounts from 55 wt .-% to 90 wt .-% and so much of polysaccharide thickening agent that it is at 20 ° C. at 20 Revolutions per minute (Brookfield rotary viscometer) a viscosity in the range from 200 mPa.s to 5000 mPa.s, in particular 300 mPa.s to 3000 mPa.s and at 5 revolutions per minute (Brookfield rotary viscometer) a viscosity of at least 1.5, in particular 2 to 50 and particularly preferably 2.5 to 30 higher viscosity than at 50 revolutions per minute.

Several measurements are necessary to determine the intrinsic viscosity. When using conventional Brookfield rotary viscometers, it is generally not possible to measure the entire viscosity range using the same spindle, but instead use the spindle prescribed for the respective measuring range.

The agents according to the invention contain, as an essential component, hydrogen peroxide, which is responsible for the bleaching performance, in amounts of preferably 0.5% by weight to 20% by weight, in particular 2% by weight to 10% by weight. To produce such agents, it is also possible to start with more concentrated hydrogen peroxide.

An optionally modified polymer of saccharides such as glucose, galactose, mannose, gulose, old rose, allose, etc. can be considered as the polysaccharidic thickening agent. A water-soluble xanthan is preferred, as it is, for example, under the product names Kelzan®. Rhodopol®, Ketrol® or Rheozan® commercially available is used. Xanthan is understood to be a polysaccharide which corresponds to that which is produced by the bacterial strain Xanthomas campestris from aqueous solutions of glucose or starch (J. Biochem. Micobiol. Technol. Engineer. Vol. III (1961), pp. 51 to 63) . It consists essentially of glucose, mannose, glucuronic acid and their acetylation products and also contains minor amounts of chemically bound pyruvic acid. It is also possible to use water-soluble polysaccharide derivatives, as can be obtained, for example, by oxyalkylation with, for example, ethylene oxide, propylene oxide and / or butylene oxide, by alkylation with, for example, methyl halides and / or dimethyl sulfate, by acylation with carboxylic acid halides or by saponifying deacetylation. The polysaccharidic thickening active ingredient is preferably contained in agents according to the invention in amounts of 0.05% by weight to 2.5% by weight, in particular 0.1% by weight to 2% by weight. It not only contributes decisively to the viscosity, but also to the structural viscosity of the agents according to the invention. It is particularly advantageous that when such thickening agents, in particular xanthan, are used, the viscosity changes only insignificantly over a wide temperature range from about -5 ° C. to 40 ° C., and values in the abovementioned viscosity range are reversibly reversed even when leaving this temperature range. if you bring the agent back to room temperature.

Agents according to the invention contain one or more surfactants in amounts of preferably 0.1% by weight to 9% by weight, anionic surfactants, nonionic surfactants and mixtures thereof being particularly suitable. Suitable anionic surfactants are, in particular, those which contain sulfate or sulfonate groups. Suitable surfactants of the sulfonate type are preferably C ₉ -C, ₃ alkyl benzene sulfonates, olefin sulfonates, ie mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C _I2 -C ₁₈ monoolefins with terminal or internal double bond, obtained by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products. Also suitable are alkanesulfonates, which are for example derived from C ₁₂ -C _I8 alkanes by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization. The esters of α- Sulphofatty acids (ester sulphonates), for example the α-sulphonated methyl esters of hydrogenated coconut, palm kernel or tallow fatty acids, which by α-sulphonation of the methyl esters of fatty acids of vegetable and / or animal origin with 8 to 20 C atoms in the fatty acid molecule and subsequent neutralization water-soluble mono salts are considered. These are preferably the α-sulfonated esters of hydrogenated coconut, palm, palm kernel or tallow fatty acids, with sulfonation products of unsaturated fatty acids, for example oleic acid, in small amounts, preferably in amounts not above about 2 to 3% by weight. %, can be present. In particular, α-sulfofatty acid alkyl esters are preferred which have an alkyl chain with no more than 4 carbon atoms in the ester group, for example methyl esters, ethyl esters, propyl esters and butyl esters. In addition to the methyl esters of α-sulfofatty acids (MES), their saponified disalts can also be used. Other suitable anionic surfactants are sulfonated fatty acid glycerol esters, which are mono-, di- and triesters as well as their mixtures, such as those produced by esterification by a monoglycerol with 1 to 3 moles of fatty acid or in the transesterification of triglycerides with 0.3 to 2 moles of glycerol be preserved. As alk (en) yl sulfates, the alkali and especially the sodium salts of the sulfuric acid half esters of C ₁₂ -C ₁₈ fatty alcohols, for example from coconut fatty alcohol, tallow fatty alcohol, lauryl, myristyl, cetyl or stearyl alcohol or the C ₁₀ -C ₂₀ oxo alcohols and those half-esters of secondary alcohols of this chain length are preferred. Also preferred are alk (en) yl sulfates of the chain length mentioned which contain a synthetic, straight-chain alkyl radical produced on a petrochemical basis and which have a degradation behavior similar to that of the adequate compounds based on oleochemical raw materials. C ₁₂ -C ₁₆ alkyl sulfates and C ₁₂ -C ₁₅ alkyl sulfates and C ₄ -C ₁₅ alkyl sulfates are particularly preferred from a washing-technical point of view. 2,3-Alkyl sulfates, which are produced, for example, in accordance with US Pat. Nos. 3,234,258 or 5,075,041 and can be obtained as commercial products from the Shell Oil Company under the name DAN®, are also suitable anionic surfactants. Also suitable are the sulfuric acid monoesters of the straight-chain or branched C ₇ -C ₂₁ alcohols ethoxylated with 1 to 6 mol ethylene oxide, such as 2-methyl branched C ₉ -C _π alcohols with an average of 3.5 mol ethylene oxide (EO) or C ₁₂ - C ₁₈ fatty alcohols with 1 up to 4 EO. Fatty acid derivatives of amino acids, for example of N-methyl taurine (taurides) and / or of N-methyl glycine (sarcosides) are suitable as further anionic surfactants. The sarcosides or sarcosinates, and in particular sarcosinates of higher and optionally mono- or polyunsaturated fatty acids such as oleyl sarcosinate, are particularly preferred. The anionic surfactants can be in the form of their sodium, potassium or ammonium salts and also as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably in the form of their sodium or potassium salts, in particular in the form of the sodium salts.

The nonionic surfactants used are preferably alkoxylated, advantageously ethoxylated, in particular primary alcohols having preferably 8 to 18 carbon atoms and an average of 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol radical has a linear or preferably 2-methyl branching may be or may contain linear and methyl-branched radicals in the mixture, as are usually present in oxo alcohol radicals. In particular, however, alcohol ethoxylates with linear residues from alcohols of native origin with 12 to 18 carbon atoms. eg from coconut, palm, tallow or oleyl alcohol, and an average of 2 to 8 EO per mole of alcohol preferred. The preferred ethoxylated alcohols include, for example, C ₁₂ -C, alcohols with 3 EO or 4 EO, C ₉ -C _π alcohols with 7 EO, C ₁₃ -C ₁₅ alcohols with 3 EO, 5 EO, 7 EO or 8 EO, C ₁₂ -C ₁₈ alcohols with 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C _I2 -C ₁₄ alcohol with 3 EO and C ₁₂ -C, ₈ - alcohol with 7 EO. The degrees of ethoxylation given represent statistical averages, which can be an integer or a fraction for a specific product. Preferred alcohol ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). The nonionic surfactants also include alkyl glycosides of the general formula RO (G) _x in which R is a primary straight-chain or methyl-branched, in particular methyl-branched aliphatic radical having 8 to 22, preferably 12 to 18, carbon atoms, and G stands for a glycose unit with 5 or 6 carbon atoms, preferably for glucose. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is arbitrary Number - which can also take fractional values as an analytical quantity - between 1 and 10; x is preferably 1.2 to 1.4. Also suitable are polyhydroxy fatty acid amides of the formula (I) in which R ³ CO is an aliphatic acyl radical having 6 to 22 carbon atoms, R ^{4 is} hydrogen, an alkyl or hydroxyalkyl radical having 1 to 4 carbon atoms and [Z] is a linear or branched polyhydroxyalkyl radical with 3 to 10 carbon atoms and 3 to 10 hydroxyl groups:

R ⁴

R ³ -CO-N- [Z] (I)

The polyhydroxy fatty acid amides are preferably derived from reducing sugars with 5 or 6 carbon atoms, in particular from glucose. The group of polyhydroxy fatty acid amides also includes compounds of the formula (II)

R ⁵ -OR ⁶

! (ii)

R'-CO-N- [Z]

in which R ^{3 represents} a linear or branched alkyl or alkenyl radical having 7 to 12 carbon atoms, R ^{5 represents} a linear, branched or cyclic alkylene radical or an arylene radical having 2 to 8 carbon atoms and R ^{6 represents} a linear, branched or cyclic alkyl radical or Aryl radical or an oxy-alkyl radical having 1 to 8 carbon atoms, C 1 -C ₄ -alkyl or phenyl radicals being preferred, and [Z] for a linear polyhydroxyalkyl radical whose alkyl chain is substituted by at least two hydroxyl groups, or alkoxylated, preferably ethoxylated or propoxylated derivatives of this radical. [Z] is also preferably obtained here by reductive amination of a sugar such as glucose, fructose, maltose, lactose, galactose, mannose or xylose. The N-alkoxy- or N-aryloxy-substituted compounds can then, for example, according to the teaching of international patent application WO 95/07331, by reaction with fatty acid methyl esters in counterparts. were an alkoxide as a catalyst in the desired polyhydroxy fatty acid amides. Another class of preferably used nonionic surfactants, which are used either as the sole nonionic surfactant or in combination with other nonionic surfactants, in particular together with alkoxylated fatty alcohols and / or alkyl glycosides, are alkoxylated, preferably ethoxylated or ethoxylated and propoxylated, fatty acid alkyl esters, preferably with 1 to 4 carbon atoms in the alkyl chain, in particular fatty acid methyl esters, as described, for example, in Japanese patent application JP 58/217598 or which are preferably prepared by the process described in international patent application WO 90/13533. Nonionic surfactants of the amine oxide type, for example, ^{'N-cocoalkyl-N,} N-dimethylamine oxide and N-tallowalkyl-N, N- dihydroxyethylamine oxide, and the fatty acid alkanolamide may be suitable. The amount of these nonionic surfactants is preferably not more than that of the ethoxylated fatty alcohols, in particular not more than half of them. So-called gemini surfactants can be considered as further surfactants. These are generally understood to mean those compounds which have two hydrophilic groups per molecule. These groups are usually separated from one another by a so-called "spacer". This spacer is usually a carbon chain, which should be long enough that the hydrophilic groups have a sufficient distance so that they can act independently of one another. Such surfactants are generally characterized by an unusually low critical micelle concentration and the ability to greatly reduce the surface tension of the water. In exceptional cases, the term gemini surfactants is understood not only to mean "dimeric" but also "trimeric" surfactants. Suitable gemini surfactants are, for example, sulfated hydroxy mixed ethers according to German patent application DE 43 21 022 or dimer alcohol bis and trimeral alcohol tris sulfates and ether sulfates according to German patent application DE 195 03 061. End group-blocked dimeric and trimeric mixed ethers according to German patent application DE 195 13 391 are particularly characterized by their bi- and multifunctionality. For example, the end-capped surfactants mentioned have good wetting properties and are low-foaming, so that they are particularly suitable for use in machine washing or Cleaning procedures are suitable. Gemini polyhydroxy fatty acid amides or poly polyhydroxy fatty acid amides as described in international patent applications WO 95/19953, WO 95/19954 and WO 95/19955 can also be used.

In a preferred embodiment, an agent according to the invention contains a surfactant system composed of alkyl ether sulfate of the general formula R'O- (CH ₂ CH ₂ O) _n -SO ₃ X, in which R ^{1 is} a linear or branched chain alkyl or alkenyl radical with 6 to 22 C- Atoms, n is a number from 1 to 10 and X is an alkali or ammonium ion, and alkyl polyglycol ethers of the general formula R ² O- (C ₃ H ₆ O) _r (CH ₂ CH ₂ O) _m - (C ₃ H ₆ O ) _n -OH, in which R ^{2 is} a linear or branched chain alkyl or alkenyl radical having 6 to 22 carbon atoms and m is a number from 1 to 10 and 1 and n is a number from 0 to 10, in a weight ratio of 1:10 to 10: 1, in particular from 2: 1 to 5: 1.

Suitable complexing agents for heavy metals contained in agents according to the invention include aminocarboxylic acids and optionally functionally modified phosphonic acids. for example hydroxy or aminoalkanephosphonic acids. The aminocarboxylic acids which can be used include, for example, nitrilotriacetic acid, methylglycinediacetic acid and diethylenetriaminepentaacetic acid. The phosphonic acids include, for example, l-hydroxyethane-l, l-diphosphonic acid (HEDP) or the disodium salt or the tetrasodium salt of this acid. Ethylene diamine tetramethylene phosphonic acid (EDTMP), diethylene triamine pentamethylene phosphonic acid (DTPMP) as well as their higher homologs in question. The N-oxides corresponding to the nitrogenous compounds mentioned can also be used. Useful complexing agents also include ethylenediamine-N, N'-disuccinic acid (EDDS). The complexing agents mentioned in their acid form can be used as such or in the form of the sodium salts. Mixtures of aminocarboxylic acids with phosphonic acids are preferred. Complexing agents for heavy metals are preferably contained in agents according to the invention in amounts of 0.05% by weight to 1% by weight.

Among the known ingredients effective as radical scavengers, which are in the invention Agents preferably contained in amounts of 0.01% by weight to 0.1% by weight include phenols such as 1,6-di-tert-butyl-4-methylphenol (butylated hydroxytoluene, BHT), hydroquinones such as di- tert-butyl hydroquinone, catechols such as allyl catechol, alkylated diphenylamines or N-phenyl-α-naphthylamines and dihydroquinolines. BHT is used as the preferred radical scavenger. In order to be able to rapidly incorporate such normally poorly water-soluble substances into agents according to the invention, it has proven useful to incorporate them in the form of a solution in a water-miscible solvent, for example a lower alcohol such as ethanol or isopropanol. It is preferred to use them in such a concentrated manner that only small amounts of such solvents, in particular at most 0.5% by weight, are introduced into the agent according to the invention.

Agents according to the invention are preferably acidic and in particular have a pH in the range from 2 to 4. To set a desired pH value which does not result from the mixture of the other components, the agents according to the invention can contain system-compatible acids, in particular the above-mentioned aminocarboxylic or phosphonic acids, citric acid, acetic acid, tartaric acid, malic acid, lactic acid, glycolic acid, succinic acid, glutaric acid and / or adipic acid, but also mineral acids such as sulfuric acid, phosphoric acid or alkali hydrogen sulfates, or bases, in particular ammonium or alkali metal hydroxides.

In addition to the ingredients mentioned, agents according to the invention can contain all other ingredients customary in liquid detergents which are compatible with the essential constituents, in particular the hydrogen peroxide and the thickening system. These include, for example, foam regulator active ingredients, colorants and fragrances and, if desired, optical brighteners.

Agents according to the invention can be produced in a relatively simple manner by simply mixing their ingredients. They are homogeneous systems with high storage stability and good stain removal performance with little potential for textile damage. They are preferably used to pretreat soiled textiles before washing them. In addition or instead, you can also put them in Use the form of an additive to a detergent, especially for machine washing of textiles. In a washing process using agents according to the invention, the procedure is preferably such that a liquid agent according to the invention is applied undiluted to the soiled textile or to a part of the soiled textile which comprises the stain to be removed, and is preferably allowed to act there only for so long that it does not dry out, and the textile is washed using water or, if appropriate, an aqueous wash liquor which contains a customary detergent, in particular using a machine. A further amount of the agent according to the invention can be added to the customary detergent and / or the aqueous wash liquor.

Examples

Liquid bleach-containing laundry pretreatment agents B1 and B2, which were adjusted to a pH of 3 by adding small amounts of phosphonic acid, and which also have the viscosity given in the table (in mPa .s at 20 ° C).

Table 1: Composition (% by weight)

a) Texapon® NSO, manufacturer Henkel KGaA b) Arlipon® FT, manufacturer Henkel KGaA c) 1: 1 mixture of Na-hydroxyethane diphosphonate and Na-methylglycine diacetate d) Brookfield rotary viscometer, spindle no. 2, 20 revolutions per minute

1 ml or 2 ml of the agents Bl or B2, depending on the size of the stains, was applied to artificially produced, standardized soiling on cotton fabric, with spread over a rubber wiper and leave on for 10 minutes. The textile sample treated in this way was then washed together with 2 kg of clean laundry using a commercially available bleach-free mild detergent powder VI (dosage 68 g) (Miele Novotronic® 918, 1-cycle method, 40 ° C short program, water hardness 16 ° dH). The reflectance of the tissue samples was measured after drying; The following table shows the color distance value (ΔΔE) from the soiled fabric. For comparison, the values which are obtained without using the agent according to the invention are also given.

Table 2: Color difference values

It can be seen that when the agent according to the invention is used, significantly more soiling is removed than with the conventional detergent without prior application of the agent according to the invention.

Claims

claims

1. Liquid water-containing bleaching or laundry pretreatment agent containing 0.2% by weight to 25% by weight of hydrogen peroxide, complexing agent for heavy metals in an amount of up to 5% by weight, surfactant in an amount of up to 15% by weight , Radical scavengers in an amount of up to 0.1% by weight and water in amounts of 55% by weight to 90% by weight and so much of a polysaccharidic thickening agent that it is at 20 ° C. at 20 revolutions per minute (Brookfield rotational viscometer) has a viscosity in the range from 200 mPa.s to 5000 mPa.s, and at 5 revolutions per minute (Brookfield rotational viscometer) has a viscosity which is at least 1.5 times higher than at 50 revolutions per minute.

2. Composition according to claim 1, characterized in that it contains polysaccharide thickening agent 0.05 wt .-% to 2.5 wt .-%, in particular 0.1 wt .-% to 2 wt .-%.

3. Composition according to claim 1 or 2, characterized in that it contains 1.5% by weight to 20% by weight, in particular 2% by weight to 10% by weight, of hydrogen peroxide.

4. Composition according to one of claims 1 to 3, characterized in that it has a viscosity by a factor of 2 to 50, in particular 2.5 to 30, higher viscosity at 5 revolutions per minute than at 50 revolutions per minute.

5. Composition according to one of claims 1 to 4, characterized in that the polysaccharide thickening agent is a xanthan.

6. Composition according to one of claims 1 to 5, characterized in that it contains 0.1 wt .-% to 9 wt .-% surfactant.

7. Composition according to one of claims 1 to 6, characterized in that it is a surfactant system of alkyl ether sulfate of the general formula R'θ- (CH ₂ CH ₂ O) _n -SO ₃ X, in which R ^{1 is} a linear or branched-chain alkyl or alkenyl radical having 6 to 22 C atoms, n is a number from 1 to 10 and X is an alkali metal or ammonium ion, and alkyl polyglycol ether of the general formula R ² O- (C ₃ H ₆ O), - (CH ₂ CH ₂ O) _m - (C ₃ H ₆ O) _n - OH, in which R ^{2 is} a linear or branched chain alkyl or alkenyl radical with 6 to 22 C atoms and m is a number from 1 to 10 and 1 and n is a number from 0 to 10, in a weight ratio of 1:10 to 10: 1, in particular from 2: 1 to 5: 1.

8. Composition according to one of claims 1 to 7, characterized in that it contains 0.05% by weight to 1% by weight of complexing agent for heavy metals.

9. Composition according to one of claims 1 to 8, characterized in that it contains 0.01 wt .-% to 0.1 wt .-% radical scavenger.

10. Agent according to one of claims 1 to 9, characterized in that it is acidic and in particular has a pH in the range from 2 to 4.

1 1. Use of an agent according to one of claims 1 to 10 for pretreating soiled textiles before washing them.

12. Use of an agent according to any one of claims 1 to 10 as an additive to a detergent in the particular machine washing of textiles.

13. A method of washing textiles, characterized in that a liquid agent according to one of claims 1 to 10 is applied undiluted to the soiled textile or part of the soiled textile, and the textile using water or an aqueous washing liquor, the one Contains common detergent, in particular washes using a machine.

14. The method according to claim 13, characterized in that an agent according to any one of claims 1 to 10 is added to the usual detergent and / or the aqueous wash liquor in addition to the amount introduced via the textile.