DE69625471T2 - PRE-LAUNDRY TREATMENT WITH PEROXYBLE FABRIC COMPLEX FOR IRON, COPPER OR MANGANE FOR REDUCED TISSUE DAMAGE - Google Patents

Abstract

The present invention relates to the use of a liquid composition comprising a peroxygen bleach and a compound chelating copper and/or iron and/or manganese, for pretreating fabrics before said fabrics are washed, whereby the loss of tensile strength in said fabrics is reduced. The present invention further encompasses a process for pretreating soiled fabrics as well as compositions suitable to be used in said process.

Description

The present invention relates to the technique of pretreating soiled textiles before washing.

Compositions containing a peroxygen bleaching agent have been extensively described in laundry applications as laundry detergents, laundry additives or even laundry pre-tenders.

Indeed, it is known to use such peroxygen bleach-containing compositions in laundry pretreatment applications to promote the removal of encrusted stains/soils which are otherwise particularly difficult to remove, such as grease, coffee, tea, grass, mud/clay-containing soils and the like. However, we have found that a disadvantage associated with such peroxygen bleach-containing compositions is that these compositions can damage fabrics when used in pretreatment applications, i.e. when applied directly to the fabrics and left on the fabrics for extended periods of time to act thereon before the fabrics are washed.

It is therefore an object of the present invention to provide improved safety for textiles when textiles are pretreated with compositions containing peroxygen bleach, particularly in those applications in which these compositions are left in contact with the textiles for extended periods of time before these textiles are washed.

When pretreating textiles with compositions containing a peroxygen bleaching agent such as hydrogen peroxide, it has been found that the presence of metal ions such as copper and/or iron and/or manganese on the surface of textiles causes damage to the textiles, resulting in a reduction in the tensile strength of the textile fibers. It is suspected that the presence of metal ions such as copper and/or iron and/or manganese on the surface of textiles, in particular on cellulose fibers, catalyzes the radical decomposition of peroxygen bleaching agents such as hydrogen peroxide. This causes a radical reaction to form free radicals on the surface of the textile, resulting in a reduction in the tensile strength.

Therefore, we found it essential that this surface radical reaction be monitored in the pretreatment environment, thereby ensuring improved textile safety.

It has now been found that the use of a compound for chelating copper and/or iron and/or manganese ions selected from the group consisting of diethylenetriaminepentamethylenephosphonic acid (DTPMP), hydroxyethanediphosphonic acid (HEDP), ethylenediamine-N,N'-disuccinic acid (EDDS), methylglycinediacetic acid (MGDA), diethylenetriaminepentaacetic acid (DTPA), propylenediaminetetraacetic acid (PDTA), 2-hydroxypyridine- N-oxide (HPNO), or ethylenedinitrilotetrakis-(methylenephosphonic acid)-N,N-dioxide in a peroxygen bleach-containing composition substantially reduces damage to a textile pretreated with such a composition.

An advantage associated with the use of a peroxygen bleach-containing composition with such a compound to chelate copper and/or iron and/or manganese in the laundry pretreatment application is that color damage is also reduced.

A further advantage of the present invention is that it provides excellent washing performance on bleachable stains as well as on the removal of grease stains.

Another advantage of the present invention is that the compositions suitable for use according to the present invention also provide excellent performance when used in other applications apart from laundry pretreatment applications, such as in other washing applications, as a laundry detergent or laundry additive, or even in hard surface cleaning applications.

It has also been found that the use of a chelating agent such as ethylenedinitrilotetrakis- (methylenediphosphonic acid)-N,N'-dioxide and/or hydroxyethanediphosphonic acid (HEDP) with two electron donor groups capable of occupying adjacent coordination sites in the coordination sphere of the metal ion so as to form complexes with metal ions in which each metal ion is complexed by 3 molecules of chelating agents such as 2-hydroxypyridine-N-oxide, allows to prepare acidic liquid compositions suitable for the pretreatment of textiles, which exhibit improved chemical stability with extended pot life.

Compositions containing peroxygen bleaching agents have been extensively described in the prior art. EP-A-629691 discloses emulsions of nonionic surfactants with a polysiloxane compound, and as optional ingredients hydrogen peroxide or a water-soluble source thereof, and chelating agents. The only chelating agent disclosed is S,S-ethylenediaminodisuccinic acid (see Examples). Although a pretreatment application for the Compositions disclosed in EP-A 629691, the use of peroxygen bleach-containing compositions with a compound which chelates copper and/or iron and/or manganese for the pretreatment of textiles, whereby the reduction in tensile strength in the textiles is reduced, is nowhere disclosed.

EP-A-629690 discloses emulsions of nonionic surfactants with a terephthalate-based polymer, and as optional ingredients hydrogen peroxide or a water-soluble source thereof, and chelating agents. The only chelating agent disclosed is S,S-ethylenediaminodisuccinic acid (see Examples). Although a pretreatment application for the compositions is disclosed in EP-A 629691, the use of peroxygen bleach-containing compositions with a compound chelating copper and/or iron and/or manganese for pretreating textiles, thereby reducing the reduction in tensile strength in the textiles, is nowhere disclosed.

EP-A-209 228 discloses compositions containing a peroxide source such as hydrogen peroxide, an aminopolyphosphonate chelating agent and a radical scavenger. Diethylenetriaminepentamethylenephosphonic acid is explicitly disclosed. EP-A-209 228 also discloses that the hydrogen peroxide-containing compositions can be used as prespotters. However, nowhere is it mentioned that peroxygen bleach-containing compositions containing a compound chelating copper and/or iron and/or manganese for pretreating textiles make it possible to reduce the reduction in tensile strength in the textiles.

The present invention relates to a use as defined in claim 1.

The present invention is based on the finding that the damage to textiles resulting in a reduction in tensile strength is reduced when compositions containing a peroxygen bleach and a compound chelating copper and/or iron and/or manganese according to the present invention are used to pretreat soiled textiles, compared to the same compositions to pretreat the textiles, but without any compound chelating copper and/or iron and/or manganese.

By "pretreating soiled textiles" is meant that the liquid composition in its pure form is applied to the soiled textile and left there to act on the textile as described below in the method for pretreating soiled textiles according to the present invention before the textile is washed.

In other words, the use of a composition containing a peroxygen bleach with a compound containing copper and/or iron and/or manganese according to the present invention to substantially reduce the reduction in tensile strength caused by the presence of copper and/or iron and/or manganese on the fabric surface, even when the composition remains on the fabric for an extended period of time, e.g. 24 hours, prior to washing the fabric, and even when the fabric is contaminated by high levels of copper and/or iron and/or manganese.

The reduction in tensile strength of a textile can be measured using the tensile strength method, as can be seen in the examples below. This method consists in measuring the tensile strength of a given textile by stretching the textile until it breaks. The force, expressed in kg, necessary to make the textile break is the "ultimate tensile strength" and can be measured with the "stress-strain INSTRON machine". By "reduction in tensile strength" is meant the difference when comparing the tensile strength of a reference textile, i.e. a textile that has not been pretreated, and the tensile strength of the same textile after it has been pretreated according to the present invention. A reduction in tensile strength of zero means that no damage to the textile was observed.

An advantage associated with the present invention is that color damage is also reduced. Indeed, the color change and/or discoloration observed when pretreating soiled colored fabrics with a composition containing a peroxygen bleach with a compound that chelates copper and/or iron and/or manganese according to the present invention is reduced compared to the color change and/or discoloration observed when the same composition is used but without any such compound chelating copper and/or iron and/or manganese, even when this composition is left on the fabrics for a prolonged period of time before the fabrics are washed. Accordingly, the present invention also encompasses the use of a liquid composition comprising a peroxygen bleach and a compound which chelates copper and/or iron and/or manganese for pretreating a soiled colored textile before said textile is washed, thereby reducing color damage to said textile.

Likewise, with liquid compositions containing a peroxygen bleach and a compound chelating copper and/or iron and/or manganese, a reduction in tensile strength reduction and/or a reduction in color damage is obtained without compromising the bleaching performance or the stain removal performance provided by these compositions.

The present invention further comprises a method for pretreating soiled textiles with a liquid composition comprising a peroxygen bleaching agent and a compound which chelates copper and/or iron and/or manganese, the method comprising the steps applying the composition in its pure form to the textile and allowing the composition to remain in contact with the textile without allowing the composition to dry on the textile before washing the textile. The composition may typically remain in contact with the textile for a period of time from 1 minute to 24 hours, preferably from 1 minute to 1 hour and more preferably from 5 minutes to 30 minutes. Optionally, when the textile is soiled with encrusted stains/soils which would be relatively difficult to remove otherwise, the compositions according to the present invention may be rubbed and/or brushed more or less intensively, for example by means of a sponge or brush or simply by rubbing two pieces of textile against each other. By "washing" is meant herein simply rinsing the textiles with water, or the textiles may be washed with conventional compositions containing at least one surfactant, using a washing machine or simply by hand.

By "in their neat form" it is meant that the compositions described herein are applied to the fabrics to be pretreated without being subjected to any dilution, i.e. they are applied as described herein.

According to the method of pretreating soiled fabrics of the present invention, the liquid compositions used in this method should not be left on the fabrics to dry. Indeed, it has been found that water evaporation contributes to increasing the concentration of free radicals on the surface of the fabrics and, consequently, the speed of the chain reaction. It is also suspected that an autoxidation reaction occurs as a result of the evaporation of water when the liquid compositions are left on the fabrics to dry. This autoxidation reaction generates peroxy radicals which can contribute to the degradation of the cellulose. Consequently, not leaving the liquid compositions on the fabrics to dry as described herein in the method of pretreating soiled fabrics according to the present invention contributes to the advantages according to the present invention, i.e. i.e., to reduce the tensile strength reduction when textiles are pretreated with liquid compositions containing peroxygen bleaching agents.

As an essential element, the compositions suitable for use according to the present invention comprise a peroxygen bleaching agent. The preferred peroxygen bleaching agent is hydrogen peroxide, or a water-soluble source thereof, or mixtures thereof. Hydrogen peroxide is most preferably used in the compositions according to the invention. As used herein, a hydrogen peroxide source refers to any compound that generates hydrogen peroxide when that compound comes into contact with water.

Suitable water-soluble sources of hydrogen peroxide for use herein include percarbonates, persilicates, persulfates such as monopersulfate, perborates, and peroxyacids such as diperoxydodecanedioic acid (DPDA), magnesium perphthalic acid, and mixtures thereof.

Typically, the compositions suitable for use herein comprise 0.5 to 20% by weight of the total composition of said peroxygen bleach, preferably 2 to 15% by weight and most preferably 3 to 10% by weight. Indeed, the presence of the peroxygen bleach, preferably hydrogen peroxide, provides powerful cleaning benefits which are particularly evident in laundry applications.

As a second essential ingredient, the compositions suitable for use herein according to the present invention comprise a compound that chelates copper and/or iron and/or manganese. Typically, the compositions suitable for use herein comprise from 0.005 to 2% by weight of the total composition of said compound capable of chelating copper and/or iron and/or manganese or mixtures thereof, preferably from 0.01 to 1% by weight and most preferably from 0.01 to 0.5% by weight.

These compounds, which can chelate copper and/or iron and/or manganese, are selected from the group listed below and mixtures thereof.

Phosphonate chelators in the form of hydroxyethane diphosphonic acid (HEDP) and ethylenedinitrilotetrakis(methylenephosphonic acid)-N,N-oxide, as well as alkali metal ethane-1-hydroxydiphosphonates, ethylenediaminetetramethylenephosphonates, and diethylenetriaminepentamethylenephosphonates. The phosphonate compounds can be present either in their acid form or as salts of various cations at some or all of their acid functionalities. Phosphonate chelators are commercially available from Monsanto under the trade name DEQUEST®. Preferred phosphonate chelators used herein are diethylenetriaminepentamethylenephosphonates, hydroxyethane diphosphonic acid (HEDP) and ethylenedinitrilotetrakis(methylenephosphonic acid)-N,N-oxide.

It has been found that hydroxyethane diphosphonic acid and ethylenedinitrilotetrakis-(methylenephosphonic acid)-N,N-oxide are particularly resistant to protonation and oxidation. Therefore, hydroxyethane diphosphonic acid and ethylenedinitrilotetrakis-(methylenephosphonic acid)-N,N-oxide are particularly suitable for use in acidic liquid compositions as a compound for chelating copper and/or iron and/or manganese according to the present invention, thereby improving textile safety. Indeed, hydroxyethane diphosphonic acid and/or ethylenedinitrilotetrakis-(methylenephosphonic acid)-N,N-oxide make it possible to obtain liquid acidic compositions containing a peroxygen-containing bleaching agent with improved chemical stability compared to the same compositions, but without the chelating agent, or in comparison to the same compositions but with a different chelating agent, e.g., diethylenetriaminepentamethylenephosphonic acid instead of this chelating agent.

A preferred biodegradable chelating agent for use herein is ethylenediamine-N,N'- disuccinic acid, or alkali metal, or alkaline earth, ammonium or substituted ammonium salts thereof, or mixtures thereof. Ethylenediamine-N,N'-disuccinic acid, particularly the (S,S) isomer, has been described in detail in U.S. Patent 4,704,233, November 3, 1987, to Hartman and Perkins. Ethylenediamine-N,N'-disuccinic acid is, for example, commercially available under the trade designation ssEDDS® from Palmer Research Laboratories.

Aminocarboxylates which are usable according to the invention as compounds which chelate copper and/or iron and/or manganese are diethylenetriaminepentaacetic acid (DTPA), propylenediaminetetraacetic acid (PDTA), which is for example commercially available from BASF under the trade name Trilon FS®, and methylglycinediacetic acid (MGDA).

These chelating agents, which have two electron donor groups capable of occupying adjacent coordination sites in the metal ion coordination sphere, include chelating agents having at least one ionized carboxylate directly adjacent to one of the following groups: a non-ionized carboxylate, a hydroxyl group, an amino group or an N-oxide group. Particularly suitable for use herein is 2-hydroxypyridine N-oxide or mixtures thereof.

For example, 2-hydroxypyridine N-oxide is commercially available under the trade name 2-hydroxypyridine N-oxide from Pyrion Chemie (Germany).

According to the present invention, liquid compositions containing a peroxygen bleach and, as a compound chelating copper and/or iron and/or manganese, propylenediaminetetraacetic acid (PDTA), methylglycinediacetic acid (MGDA), diethylenetriaminepentamethylenephosphonate (DTPMP), hydroxyethanediphophonic acid (HEDP), ethylenediamine-N,N'-disuccinic acid (EDDS), 2-hydroxypyridine-N-oxide (HPNO), and/or ethylenedinitrilotetrakis-(methylenephosphonic acid), provide virtually no tensile strength reduction in fabrics pretreated therewith, i.e., the fabric durability is not reduced, even at extended contact times of the compositions with the fabrics, e.g., 24 hours.

The compositions according to the present invention are aqueous, liquid cleaning compositions. These aqueous compositions typically have a pH of from 1 to 9, preferably from 2 to 6 and most preferably from 3 to 5. The pH of the compositions can be adjusted by the use of organic or inorganic acids or alkalizing agents.

The compositions according to of the present invention may further contain a variety of optional ingredients such as free radical scavengers, surfactants, skeletal substances, stabilizers, other chelating agents, stain suspending agents, dye transfer agents, solvents, brighteners, perfumes, antioxidants, suds suppressors and dyes.

A preferred optional ingredient of the compositions according to the present invention is a radical scavenger or mixtures thereof. Suitable radical scavengers for use herein include the well-known substituted mono- and dihydroxybenzenes and their analogues, alkyl and aryl carboxylates and mixtures thereof. Preferred radical scavengers for use herein include butylhydroxytoluene, hydroquinone, di-ter-butylhydroxyquinone, mono-t-butylhydroxyquinone, tert-butylhydroxyanisole, benzoic acid, toluic acid, catechol, t-butylcatechol, benzylamine, 1,1,3-tris(2- methyl-4-hydroxy-5-t-butylphenyl)butane, commercially available under the trade name Topanol CA® ex ICI, as well as n-propyl gallate. Radical scavengers, when used, are typically present in amounts between 0.001 and 2% by weight of the total composition and preferably between 0.001 and 0.5% by weight.

The compositions according to the present invention may further contain any surfactant known to those skilled in the art, including nonionic, anionic, cationic, zwitterionic or amphoteric surfactants. The compositions according to the present invention preferably comprise any of the nonionic surfactants described below or mixtures thereof and/or any of the anionic surfactants described below or mixtures thereof. Typically, the compositions of the present invention may contain up to 50% by weight of the total composition of surfactant or mixtures thereof.

The compositions of the present invention may also comprise, as a highly preferred optional ingredient, a liquid hydrophobic bleach activator. By bleach activator herein is meant a compound which reacts with hydrogen peroxide to form a peracid. The peracid so formed is the activated bleach. By "hydrophobic bleach activator" herein is meant an activator which is not substantially and stably miscible with water. Typically, such hydrophobic bleach activators have an HLB below 11. Such suitable liquid hydrophobic bleach activators typically belong to the class of esters, amides, imides or anhydrides. A particular family of bleach activators of interest has been disclosed in EP 624 154 and particularly preferred in this family is acetyl triethyl citrate (ATC). ATC has the additional advantages of being environmentally friendly in that it ultimately breaks down into citric acid and alcohol. Furthermore, ATC shows good hydrolytic stability in the compositions herein and it is an effective bleach activator. Finally, it provides a good build-up capacity for the compositions. It is also possible to use mixtures of liquid hydrophobic bleach activators mentioned herein. The compositions mentioned herein may comprise up to 20% by weight of the total composition of bleach activator or mixtures thereof, preferably 2 to 10, most preferably 3 to 7% by weight.

When the peroxygen bleach-containing compositions according to the present invention further comprise a liquid hydrophobic bleach activator, it is highly desirable for stability reasons to prepare the compositions either as aqueous emulsions of surfactants comprising said liquid hydrophobic bleach activator or as a microemulsion of said liquid hydrophobic bleach activator in a matrix comprising water, the peroxygen bleach and a hydrophilic surfactant system comprising an anionic and a non-ionic surfactant.

In the embodiment of the present invention in which the peroxygen bleach-containing compositions of the present invention further comprise the bleach activator and are prepared as aqueous emulsions, the peroxygen bleach-containing emulsions comprise an emulsifying surfactant system of at least two different surfactants, i.e., at least one hydrophobic surfactant having an HLB up to 9 and at least one hydrophilic surfactant having an HLB above 10, to emulsify the liquid hydrophobic bleach activator. Indeed, these two different surfactants must have different HLB (hydrophilic-lipophilic balance) values to form stable emulsions, and preferably the difference in the value of the two HLBs is at least 1, preferably at least 3. In other words, by appropriately combining at least two of the surfactants with different HLBs in water, stable emulsions are formed, i.e., emulsions that do not significantly separate into different layers after standing at 50ºC for at least two weeks.

The emulsions according to the present invention comprise 2 to 50% by weight of the total composition of the hydrophilic and hydrophobic surfactants, preferably 5 to 40% by weight, and more preferably 8 to 30% by weight. The emulsions according to the present invention comprise at least 0.1% by weight of the total emulsion of the hydrophobic surfactant or mixtures thereof, preferably at least 3% and more preferably at least 5% and at least 0.1% by weight of the total emulsion of the hydrophilic surfactant or mixtures thereof, preferably at least 3% and more preferably at least 6%.

Preferred for use herein are the hydrophobic nonionic surfactants and hydrophilic nonionic surfactants. The hydrophobic nonionic surfactants to be used herein have an HLB up to 9, preferably below 9, more preferably below 8, and the hydrophilic surfactants have an HLB above 10, preferably above 11, more preferably above 12. In fact, the hydrophobic nonionic surfactants to be used herein have excellent grease-reducing properties, that is, they exhibit a solvent effect that contributes to the removal of hydrophobic stains. The hydrophobic surfactants act as carriers the hydrophobic brighteners onto the textiles, thereby enabling these brighteners to act in close proximity to the surface of the textile from the beginning of the wash.

Suitable nonionic surfactants for use herein include alkoxylated fatty alcohols, preferably fatty alcohol ethoxylates and/or propoxylates. Indeed, a wide variety of such alkoxylated fatty alcohols are commercially available, having very different HLB (hydrophilic lipophilic balance-hydrophilic-lipophilic balance) values. The HLB values of such alkoxylated nonionic surfactants depend significantly on the chain length of the fatty alcohol, the nature of the alkoxylation and the degree of alkoxylation. Hydrophilic nonionic surfactants tend to have a high degree of alkoxylation and a short chain fatty alcohol, while hydrophobic surfactants tend to have a low degree of alkoxylation and a long chain fatty alcohol. Surfactant catalogues are available which list a number of surfactants, including nonionics, together with their corresponding HLB values.

Suitable chemical processes for preparing the nonionic surfactants for use herein include condensation of the corresponding alcohols with alkylene oxide in the desired proportions. Such processes are well known to those skilled in the art and have been extensively described in the art. Alternatively, a wide variety of alkoxylated alcohols suitable for use herein are commercially available from various suppliers.

Preferred hydrophobic nonionic surfactants used according to the present invention are surfactants having an HLB up to 9 and corresponding to the formula RO-(C2H4O)n(C3H6O)mH, wherein R is a C6 to C22 alkyl chain or a C6 to C28 alkylbenzyl chain, and wherein n + m is from 0.5 to 5, and n is from 0 to 5, and m is from 0 to 5, and preferably n + m is from 0.4 to 4, and n and m are from 0 to 4. The preferred R chains for use herein are the C8 to C22 alkyl chains. Correspondingly suitable hydrophobic nonionic surfactants for use herein are Dobanol® 91-2.5 (HLB = 8.1; R is a mixture of C₉- and C₁₁₅-alkyl chains, n is 2.5 and m is 0), or Lutensol® TO3 (HLB = 8; R is a mixture of C₁₃- and C₁₅-alkyl chains, n is 3 and m is 0), or Tergitol® 25L3 (HLB = 7.7; R is in the range of C₁₂- to C₁₅-alkyl chain length, n is 3 and m is 0), or Dobanol® 23-3 (HLB = 8.1; R is a mixture of C₁₂- and C₁₃-alkyl chains, n is 3 and m is 0), or Dobanol® 23-2 (HLB = 6.2; R is a mixture of C₁₂ and C₁₃ alkyl chains, n is 2 and m is 0), or mixtures thereof. Preferred herein are Dobanol® 23-3, or Dobanol® 23-2, Lutensol® TO3, or mixtures thereof. The Dobanol® surfactants are commercially available from SHELL. The Lutensol® surfactants are commercially available from BASF and the Tergitol® surfactants are commercially available from UNION CARBIDE. Other suitable hydrophobic nonionic surfactants for use herein are non-alkoxylated surfactants. An example is Dobanol® 23 (HLB < 3).

Preferred hydrophilic nonionic surfactants used according to the present invention are surfactants having an HLB above 10 and corresponding to the formula RO-(C₂H₄O)n(C₃H₆O)mH, wherein R is a C₆ to C₂₂ alkyl chain or a C₆ to C₂₈ alkylbenzyl chain, and wherein n + m is from 5 to 11, and n is from 0 to 11, and m is from 0 to 11, and preferably n + m is from 6 to 10, and n and m are from 0 to 10. Throughout the specification, n and m refer to the average of the ethoxylation/propoxylation. The preferred R chains for use herein are the C8 to C22 alkyl chains. Correspondingly suitable hydrophilic nonionic surfactants for use herein are Dobanol® 23-6.5 (HLB = 11.9; R is a mixture of C₁₂- and C₁₃-alkyl chains, n is 6.5 and m is 0), or Dobanol® 25-7 (HLB = 12; R is a mixture of C₁₂- to C₁₅-alkyl chains, n is 7 and m is 0), or Dobanol® 45-7 (HLB = 11.6; R is a mixture of C₁₄- and C₁₅-alkyl chains, n is 7 and m is 0), or Dobanol® 91-5 (HLB = 11.6; R is a mixture of C₁₄- to C₁₅-alkyl chains, n is 5 and m is 0), or Dobanol® 91-6 (HLB = 12.5; R is a mixture of C₉ to C₁₁₁ alkyl chains, n is 6 and m is 0), or Dobanol® 91-8 (HLB = 13.7; R is a mixture of C₉ to C₁₁₁ alkyl chains, n is 8 and m is 0), or Dobanol® 91-10 (HLB = 14.2; R is a mixture of C₉ to C₁₁₁ alkyl chains, n is 10 and m is 0), or mixtures thereof. Preferred herein are Dobanol® 91-10, or Dobanol® 45-7, Dobanol® 23-6.5, or mixtures thereof. The Dobanol® surfactants are commercially available from SHELL. Apart from the hydrophilic nonionic surfactants, other hydrophilic surfactants can also be used in the emulsions of the present invention, such as anionic surfactants described below.

The emulsions according to the present invention may further comprise other surfactants, which, however, should not significantly alter the weighted average HLB value of the entire emulsion.

In a particularly preferred embodiment of the emulsions of the present invention, wherein the emulsions contain acetyl triethyl citrate as bleach activator, an adequate nonionic surfactant system would contain a hydrophobic nonionic surfactant having, for example, an HLB of 6, such as for example Dobanol® 23-2 and a hydrophilic nonionic surfactant having, for example, an HLB of 15, such as Dobanol® 91-10. Other suitable nonionic surfactant systems include, for example, a Dobanol® 23-6.5 (HLB approximately 12) and a Dobanol® 23 (HLB below 6) or a Dobanol® 45-7 (HLB = 11.6) and Lutensol® TO3 (HLB = 8).

In the embodiment of the present invention in which the peroxygen bleach-containing compositions of the present invention contain the bleach activator and are prepared as microemulsions, the peroxygen bleach-containing microemulsions of the present invention comprise a hydrophilic surfactant system comprising an anionic surfactant and a nonionic surfactant. A key factor in stably incorporating the hydrophobic activator is that at least one of the surfactants must have a different HLB value from that of the hydrophobic activator. Indeed, if all of the surfactants had the same HLB value as that of the hydrophobic activator, a stable single phase could be formed and thus the chemical stability of the bleach/bleach activator system could be lowered.

Preferably, at least one of the surfactants has an HLB value that differs from that of the bleach activator by at least 1.0 HLB units, preferably 2.0.

Suitable anionic surfactants herein include water soluble salts or acids of the formula ROSO₃M, wherein R is preferably a C₁₀-C₂₄ hydrocarbon, preferably an alkyl or hydroxyalkyl having a C₁₀-C₂₀ alkyl moiety, more preferably a C₁₂-C₁₈ alkyl or hydroxyalkyl, and M is hydrogen or a cation, e.g. B., an alkali metal cation (e.g., sodium, potassium, lithium), or an ammonium or substituted ammonium cation (e.g., methyl-, dimethyl-, and trimethylammonium cations and quaternary ammonium cations such as tetramethylammonium and dimethylpiperidine cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like). Typically, alkyl chains of C₁₂₋₁₆ are preferred for lower wash temperatures (e.g., below about 50°C) and C₁₆₋₁₈ alkyl chains are preferred for higher wash temperatures (e.g., above about 50°C).

Other suitable anionic surfactants for use herein are water-soluble salts or acids of the formula RO(A)mSO₃M, wherein R is an unsubstituted C₁₀-C₂₄ alkyl or hydroxyalkyl group having a C₁₀-C₂₄ alkyl moiety, preferably C₁₂-C₂₀ alkyl or hydroxyalkyl, more preferably C₁₂-C₁₈ alkyl or hydroxyalkyl, A is an ethoxy or propoxy moiety, m is greater than zero, typically between about 0.5 and about 6, more preferably between about 0.5 and about 3, and M is H or a cation which is, for example, a metal cation (e.g., sodium, potassium, lithium, calcium, magnesium, etc.), an ammonium or substituted ammonium cation. Both alkyl ethoxylated sulfates and alkyl propoxylated sulfates are contemplated herein. Specific examples of substituted ammonium cations include methyl, dimethyl, trimethylammonium and quaternary ammonium cations such as, for example, tetramethylammonium, dimethylpiperidinium and cations derived from alkanolamines such as, for example, ethylamine, diethylamine, triethylamine, mixtures thereof and the like. Exemplary surfactants are C12-C18 alkyl polyethoxylate (2,25) sulfate C12-C18E(2,25)M), C12-C18 alkyl polyethoxylate (3,0) sulfate C12-C18E(3,0), and C12-C18 alkyl polyethoxylate (4,0) sulfate C12-C18E(4,0)M), wherein M is suitably selected from sodium and potassium.

Other anionic surfactants useful for detersive purposes may also be used herein. These may include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of soap, C9-C20 linear alkylbenzenesulfonates, C8-C22 primary or secondary alkylsulfonates, C8-C24 olefinsulfonates, sulfonated polycarboxylic acids prepared by sulfonation of the pyrolyzed product of alkyl metal citrates, e.g. as described in British Patent Specification No. 1,082,179, C8-C24 alkyl polyglycol ether sulfates (containing up to 10 moles of ethylene oxide); Alkyl ester sulfonates such as C₁₄₋₁₆-methyl ester sulfonates; acylglycerol sulfonates, fatty oleyl glycerol sulfonates, alkylphenol ethylene oxide ether sulfates, paraffin sulfonates, alkyl phosphates, Isothionates such as the acyl isothionates, N-acyl taurates, alkyl succinates and sulfosuccinates, monoesters of sulfosuccinate (particularly saturated and unsaturated C₁₂-C₁₈ monoesters), diesters of sulfosuccinate (particularly saturated and unsaturated C₆-C₁₄ diesters), sulfates of alkyl polysaccharides such as the sulfates of alkyl polyglucoside (the nonionic, non-sulfurized compounds being described below), branched primary alkyl sulfates, alkyl polyethoxycarboxylates such as those of the formula RO(CH₂CH₂O)kCH₂OO-M⁺, where R is a C₈-C₂₂ alkyl, k is an even number from 0 to 10, and M is a soluble, salt-forming cation. Resin acids and hydrogenated resin acids are also suitable, such as rosin, hydrogenated rosin, and resin acids and hydrogenated resin acids present in or derived from tall oil. Further examples are given in "Surface Active Agents and Detergents" (Volumes I and II by Schwartz, Perry and Berch). A variety of such surfactants are also generally disclosed in U.S. Patent 3,929,678, issued December 30, 1975 to Laughlin, et al., at column 23, line 58 through column 29, line 23 (incorporated herein by reference).

Suitable nonionic surfactants for use in the microemulsions herein include the hydrophilic nonionic surfactants as defined hereinbefore.

The preferred preparation of the microemulsions of the present invention comprising a liquid hydrophobic bleach activator involves premixing the surfactants with water and then adding the other ingredients including hydrogen peroxide and the hydrophobic bleach activator. Notwithstanding this preferred order of addition, it is important that during mixing of the ingredients the microemulsions are kept constantly under agitation at relatively high agitation energies, preferably at 750 revolutions per minute for 30 minutes, most preferably at 1000 revolutions per minute.

In the embodiment of the present invention in which the compositions are formulated as microemulsions, the compositions are macroscopically transparent in the absence of opacity enhancing agents and dyes. Upon centrifugation examination, the microemulsions herein were observed to show no phase separation after 15 minutes at 6000 revolutions per minute. Upon microscopic examination, the microemulsions appeared as a dispersion of droplets in a matrix. The matrix is the hydrophilic matrix described above and the droplets are formed by the liquid hydrophobic bleach activator. We observed that the particles had a size typically around or below 3 microns in diameter.

The compositions suitable for use according to the present invention may further comprise a foam suppressor such as 2-alkylalkanol, or mixtures thereof, as a highly preferred optional ingredient. Particularly suitable for use in the present invention are the 2-alkylalkanols having a 6 to 16, preferably 8 to 12 Carbon atoms and a terminal hydroxyl group, wherein the alkyl chain is substituted in the α-position by an alkyl chain containing 1 to 10, preferably 2 to 8, and more preferably 3 to 6 carbon atoms. Such suitable compounds are, for example, commercially available in the Isofol® series such as Isofol® 12 (2-butyloctanol) or Isofol® 16 (2-hexyldecanol). Typically, the compositions useful herein comprise 0.05 to 2% by weight of the total composition of a 2-alkylalkanol, or mixtures thereof, preferably 0.1 to 1.5% and most preferably 0.1 to 0.8%.

Although the preferred application of the compositions described herein is laundry pretreatment, the compositions according to the present invention can also be used as a laundry detergent or laundry detergent enhancer as well as a household cleaner in the bathroom or kitchen. When used as a hard surface cleaner, such compositions are easy to rinse and provide good shine properties on the cleaned surfaces.

The present invention is further illustrated by the following examples.

A) Experimental data

The following compositions were prepared by mixing the listed ingredients in the listed proportions (wt.% unless otherwise stated).

50 ppm copper per gram of textile

Pretreatment 24 hours

S,S EDDS is ethylenediamine-N,N'-disuccinic acid (S,S isomer).

DTPMP is diethylenetriamine pentamethylene phosphonate, sold by Monsanto under the trade name DEQUEST®.

MGDA is methylglycinediacetic acid

PDTA is propylenediaminetetraacetic acid, sold by BASF under the trade name FS®.

Composition I comprises hydrogen peroxide only and is free of compounds that chelate copper and/or iron and/or manganese. Compositions II to VI are representative of the present invention and comprise hydrogen peroxide and a compound that chelates copper and/or iron and/or manganese.

The following test was performed:

A tensile strength test procedure was performed on the above compositions. This test procedure was performed on metal contaminated textiles.

Cotton tapes (dimension 12.5 x 12.5 cm²) with a copper concentration of 50 ppm per gram of cotton were pretreated according to the present invention. In fact, the cotton tapes were pretreated with 2 ml of each of the compositions described herein. The compositions were left in contact with the tapes for 24 hours before being rinsed with water. After that, the damage to the textiles, i.e. the cotton tapes, was examined by stretching the tapes until they broke. The force necessary to break the tapes, i.e. the final tensile strength, was measured in the wet state with the "stress-strain INSTRON machine". The lower the force necessary to break the tapes, the worse the damage caused to the textiles. Regarding the results, a good confidence level (standard deviation = 2-5 kg) is obtained using five repetitions for each test.

The above-mentioned tensile strength reduction for the various compositions tested is expressed in percent and is obtained by comparing the tensile strength of a given textile as reference, i.e., a textile that has not been pretreated, with the tensile strength of the same textile, measured after the textile has been pretreated as mentioned above.

The above results clearly demonstrate the unexpected safety improvement, ie, the reduction in tensile strength reduction, obtained by using liquid compositions according to the present invention with a peroxygen bleach and a compound chelating copper and/or iron and/or manganese, compared to using the same compositions but without any compound chelating copper and/or iron and/or manganese. chelated (composition I). In fact, practically no reduction in tensile strength is observed when textiles are pretreated with compositions according to the present invention (see compositions II to VI), even with a prolonged contact period, ie, 24 hours, and in the presence of a high concentration of copper on the surface of the textile, ie, 50 ppm per gram of cotton textile.

B) Examples

The following compositions were prepared by mixing the listed ingredients in the listed proportions (wt.% unless otherwise stated).

S,S EDDS is ethylenediamine-N,N'-disuccinic acid (S,S isomer).

DTPMP is diethylenetriamine pentamethylene phosphonate, sold by Monsanto under the trade name DEQUEST®.

MGDA is methylglycinediacetic acid

PDTA is propylenediaminetetraacetic acid, sold by BASF under the trade name FS®.

HPNO is 2-hydroxypyridine N-oxide.

HEDP is hydroxyethane diphosphonic acid.

DTPA is diethylenetriaminepentaacetic acid.

The compositions in Examples VII-XIX are in accordance with the present invention. A pretreatment process was carried out in accordance with the present invention with Compositions VII-XIX with virtually no reduction in tensile strength of the treated fabrics, even when the compositions were left to act on the fabrics for 24 hours before the fabrics were washed.

Claims (5)

1. Use of a compound capable of complexing copper and/or iron and/or manganese ions in an aqueous liquid composition of pH 1-9 comprising a peroxygen bleaching agent, and wherein the liquid composition is used for pretreating a soiled textile before the textile is washed, characterized in that the compound capable of complexing copper and/or iron and/or manganese ions is used in the composition to reduce the loss of tensile strength in the textile resulting from the pretreatment compared to the loss of tensile strength resulting from the pretreatment of the soiled textile with the same composition without the compound, and wherein the compound is selected from the group consisting of ethylenediamine-N,N'-disuccinic acid or alkali metal salts thereof or alkaline earth metal salts thereof, ammonium or substituted ammonium salts thereof, or diethylenetriaminepentaacetic acid or methylglycinediacetic acid or diethylenetriaminepentamethylenephosphonic acid or hydroxyethanediphosphonic acid or propylenediaminetetraacetic acid or 2-hydroxypyrridine-N-oxide or ethylenedinitrilotratetrakis(methylenephosphonic acid)-N,N-oxide or mixtures thereof. 2. Use or method according to at least one of the preceding claims, wherein the liquid composition comprises 0.005 to 2% by weight of the total composition of the compound complexing copper and/or iron and/or manganese or mixtures thereof, preferably 0.01 to 1% by weight and more preferably 0.01% to 0.5%. 3. Use or method according to at least one of the preceding claims, wherein the peroxygen bleaching agent is hydrogen peroxide. 4. Use or method according to at least one of the preceding claims, wherein the composition comprises 0.5 to 20% by weight of the total composition of the peroxygen bleach or mixtures thereof, preferably 2% to 15% and more preferably 3% to 10%. 5. Use or method according to at least one of the preceding claims, wherein the composition further comprises a surfactant up to a content of 50% by weight of the total composition.