GB2423093A - Detergent comprising EDDS and a peroxygen bleach and use thereof - Google Patents

Abstract

A detergent and a process for washing a fabric dyed with a bleach sensitive dye by contacting the coloured fabric with a detergent comprising ethylenediamine succinic acid (EDDS) and a peroxygen bleach, such as percarbonate or hydrogen peroxide. Optionally the washing composition comprises a bleach activator, such as tetra acetyl ethylene diamine (TAED). At least 70% of the chelating agent present is EDDS and EDDS can be present in an amount of at least 0.1 wt%. The peroxygen bleach can be present in an amount of 5-20 wt%. The fabric can be in contact with the washing composition for a period of at least 20 minutes at a temperature of at least 50 {C. EDDS is used for preventing bleaching of a fabric dyed with a bleach sensitive dye.

Description

PROCESS

This invention relates to a process for washing a dyed fabric. The process relates to washing a fabric the dye of which is sensitive to bleach.

Detergent compositions have been studied in great detail by leaders in the detergent market. It was identified in the mid 1980's that phosphonates present as chelating agents in laundry detergents may accumulate in the environment. Governments legislated against the use of such components. The chelate ethylenediamine-N,N'-disuccinic acid (EDDS) represented by the formula:

O A

OH ( OH

OH

H II

and in particular the (S,S) isomeric form was identified as an alternative, US 4704233 teaches that EDDS provides superior stain removal of tea, grape juice, blood, and grass.

Further modifications to these basic detergent compositions have been taught in the art.

For example WO 9403553 teaches peroxide stabilisation, especially at temperatures greater than 60 C compared to EDTA. WO 9403554 teaches improved storage stability of bleach compositions, particularly acidic compositions. It further relates to removal of inorganic deposits from fabric e.g. Ca, Mg, but also Zn, Fe, Mn, Cu by use of EDDS in combination with layered sodium silicates. WO 9606908 teaches that EDDS as "builder" at a concentration of greater than 10% controls Ca hardness.

WO 9621714 discusses that Cu and Ni interact with fabric dyes and change their perceived hue in the rinse stage. Dyes darken and become drab. Also optical brighteners are affected reducing fluorescence of whites. Chelants such as EDDS are taught to prevent this. This may result from superior Cu and transition metal chelation.

WO 9528463 teaches that one can reduce the amount of expensive per-oxygen bleach components (such as perborate and TAED) by using EDDS. In WO 9720907 it is discussed that EDDS has an oxidisable amino linkage which is denatured at fabric surface by hydrophobic bleaches. However, WO 9720907 teaches that EDDS is still effective in solution to sequester transition metal ions and prevent bleach decomposition.

WO 9900478 relates to use of EDDS to prevent heavy metal ions binding to enzyme active site thus preventing OH radical destruction of the enzyme.

In WO 9902636 it is taught that transition metals progressively build up on fabric in multi- cycles which reduces whiteness and cleanness of fabric, in addition to impacting on the stability of bleach system. EDDS and a cellulase are taught to prevent this build-up. WO 9913040 discloses using EDDS Mg salt prevents the EDDS from removing transition - metal from a spray drying tower during processing. This increases stability of the formulation and chelation ability during the wash US 5929012 teaches that Cu, Fe and Mn on a fabric surface cause fabric damage and loss of tensile strength. Cellulosic materials are vulnerable as a result of radical decomposition of H202 and free radical formation. EDDS is a preferred biodegradable chelant.

The present invention alleviates the problems of the prior art.

In a first aspect the present invention provides a process for washing a fabric dyed with a bleach sensitive dye, said process comprising contacting the bleach sensitive dyed fabric with a washing composition comprising (i) ethylenediaminedisuccinic acid (EDDS) or a salt thereof; (ii) a peroxygen bleach; and optionally (iii) a bleach activator In a second aspect the present invention provides use of ethylenediaminedisuccinic acid (EDDS) or a salt thereof for preventing or reducing bleaching of a fabric dyed with a bleach sensitive dye by a bleach.

In a third aspect the present invention provides a detergent composition comprising (i) ethylenediaminedisuccinic acid (EDOS) or a salt thereof; (ii) a peroxygen bleach; and optionally (iii) a bleach activator.

We have surprisingly found that by that by providing a process/use/composition in which a bleaching agent is present and in which EDDS is present it is possible to wash fabric dyed with dyes which would otherwise be unacceptable bleached by the bleaching agent.

Laundry detergents containing bleaching agents are better than laundry detergents not containing bleaching agents at removing unwanted stains. It is normal to wash white clothes with a detergent containing bleaching agents for this reason. However, coloured fabrics can not normally be washed using a detergent containing bleach because it will fade the dyes or change the shades of the clothing. The fading or shade change may be worse after multiple washes with a detergent containing bleach, and is worse for darker colours. A change in shade happens when a piece of clothing dyed with a mixture of bleach sensitive and bleach insensitive dyes is washed in a detergent containing bleach. It is known that certain dyes are more susceptible to fading than others when washed with a detergent containing bleach, and these are well-known to those skilled in the art as "bleach-sensitive dyes". Surprisingly, we have found that if a bleach-containing laundry detergent is formulated with EDDS the fading of bleach- sensitive dyes is much reduced. The advantage of this invention is that a detergent containing bleach can be formulated that can be used on coloured fabrics, especially those fabrics that are dyed with bleachsensitive dyes. Such a detergent has the advantage of giving the superior stain removal of the bleach whilst protecting the colours from fading or shade change.

The scope of the term "bleach sensitive" is understood by one skilled in the art.

For ease of reference these and further aspects of the present invention are now discussed under appropriate section headings. However, the teachings under each section are not necessarily limited to each particular section.

PREFERRED ASPECTS

EDDS

In one preferred aspect the EDDS is (S,S)-ethylenediaminedisuccinic acid or a salt thereof.

In one preferred aspect the EDDS is ethylenediaminedisuccinic acid.

In one preferred aspect the EDDS is (S,S)-ethylenediaminedisuccinic acid.

The EDDS may be present in any amount necessary to achieve the aims of the present invention. In one aspect the EDDS comprises at least 50 wt% of chelating agents present in the washing composition based on the content of chelating agents, such as at least 60 wt%, or at least 70 wt%, or at least 80 wt%, or at least 85 wt%, or at least 90 wt%, or at least 92 wt%, or at least 95 wt%, or at least 98 wt%, or at least 99 wt%, of chelating agents present in the washing composition based on the content of chelating agents We have surprisingly found that not only is the presence of EDDS important for achieving the advantages of the present invention but the absence of other chelating agents such as phosphonate chelating agents may also be important in achieving these advantages. Thus in one preferred aspect the washing composition is substantially free of phosphonate chelating agents. By substantially free it is meant that phosphonate chelating agents are not present in an amount such that the functionality of the EDDS is effected.

In one preferred aspect the washing composition is substantially free of chelating agents other than EDDS. By substantially free it is meant that other chelating agents are not present in an amount such that the functionality of the EDDS is effected.

In one aspect the EDDS is present in an amount of at least 0.1 wt% based on the washing composition. Typical amount are at least 0.2 wt% based on the washing composition, at least 0.4 wt% based on the washing composition, 0.05 to 0.5 wt% based on the washing composition, and 0.1 to 0.4 wt% based on the washing composition.

As noted above, the EDDS may be provided in salt form. The EDDS salt may be selected from calcium, magnesium, ammonia, ammonium compounds (including ammonium hydroxide), organic amines, sodium hydroxide, potassium hydroxide and mixtures thereof.

In one aspect the EDDS may be prepared in accordance with the teaching of EDDS for use in the present invention may be prepared, for instance, by the process disclosed US-A-3158635. US-A-3158635 discloses reacting maleic anhydride (or ester or salt) with a polyamine corresponding to the desired polyamino disuccinic acid under alkaline conditions. The reaction yields a number of optical isomers, for example, the reaction of ethylenediamine with maleic anhydride yields a mixture of three optical isomers [R,R], [S,S] and [S,R] ethylenediamine disuccinic acid (EDDS) because there are two asymmetric carbon atoms in ethylenediamine disuccinic acid. These mixtures are used as mixtures or alternatively separated by means within the state of the art to obtain the desired isomer(s). Alternatively, [S,S] isomers are prepared by reaction of such acids as L-aspartic acid with such compounds as 1,2-dibromoethane as described by Neal and Rose, "Stereospecific Ligands and Their Complexes of Ethylenediaminedisuccinic Acid", Inorganic Chemistry, v. 7. (1968), pp. 2405-2412.

Peroxvqen Bleach The peroxygen bleach may be any suitable peroxygen bleach. Suitable compounds are disclosed in WO 94/03553 as peroxy compounds.

The peroxygen bleach may be hydrogen peroxide or any of the addition compounds of hydrogen peroxide, or organic peroxyacid, or mixtures thereof. By addition compounds of hydrogen peroxide it is meant compounds which are formed by the addition of hydrogen peroxide to a second chemical compound, which may be for example an inorganic salt, urea or organic carboxylate, to provide the addition compound. Examples of the addition compounds of hydrogen peroxide include inorganic perhydrate salts, the compounds hydrogen peroxide forms with organic carboxylates, urea, and compounds in which hydrogen peroxide is clathrated.

Examples of inorganic perhydrate salts include perborate, percarbonate, perphosphate, persulfate and persilicate salts. The inorganic perhydrate salts are normally the alkali metal salts. Salts in which hydrogen peroxide is clathrated are described in GB-A-1494953.

Sodium percarborate is a suitable inorganic perhydrate for use in the present invention.

This may be incorporated as either the monohydrate of empirical formula NaBO2.H202.3H20.

The compositions of the invention may and any compositions into which they may be incorporated may be of essentially any physical form such as solid, including powders, bars and granules, or fluid, including liquids, gels and pastes. When the peroxygen bleach is hydrogen peroxide however, the bleaching composition will generally comprise a concentrated solution of the hydrogen peroxide together with the EDDS. When the peroxygen bleach is an inorganic perhydrate salt the composition will generally be solid, preferably granular in nature. The inorganic perhydrate salt may be included in such a granular composition as the crystalline solid without additional protection. For certain perhydrate salts however, the preferred executions of such granular compositions utilize a coated form of the material which provides better storage stability for the perhydrate salt in the granular product.

Sodium percarbonate, is perhydrate which may be included in compositions in accordance with the invention, is an addition compound having a formula corresponding to 2Na2C03.3H202, and is available commercially as a crystalline solid.

Potassium peroxymonopersulfate is another inorganic perhydrate salt of usefulness in the compositions. The corresponding organic peroxyacid, namely peroxymonopersulfuric acid is also useful.

In a preferred aspect the peroxygen bleach is a percarbonate.

In a preferred aspect the peroxygen bleach is a perborate salt.

In a preferred aspect the peroxygen bleach is a sodium perborate.

The peroxygen bleach may be present in any suitable amount. In one aspect the peroxygen bleach is present in an amount of 5-20 wt% based on the washing composition. More preferably it is present in amounts of 5-15 wt% based on the washing composition, 7-15 wt% based on the washing composition, 8-14 wt% based on the washing composition, 10-14 wt% based on the washing composition, 11-13 wt% based on the washing composition, or approximately 12 wt% based on the washing composition.

Bleach Activator The bleach activator of the present invention is optional. However in one aspect of the present invention, the bleach activator is present.

The bleach activator may be any suitable bleach activator. Suitable compounds are disclosed in WO 94/03553 as peroxy acid bleach precursors.

The bleach activator may contain one or more N-or 0-acyl groups, which precursors can be selected from a wide range of classes. Suitable classes include anhydrides, esters, imides and acylated derivatives of imidazoles and oximes, and examples of useful materials within these classes are disclosed in GB-A-1586789, GB-A-836988, GB-A- 864,798, GB-A-1147871 and GB-A-2143231 and imides such as are disclosed in GB-A- 855735 and GB-A-1246338.

Suitable bleach activators are the N,N,N1,N1 tetra acetylated compounds disclosed in WO 94/03553. Examples include tetra acetyl methylene diamine (TAMD) in which x 1, tetra acetyl ethylene diamine (TAED) in which x=2 and tetraacetyl hexylene diamine (TAHD) in which x=6. These and analogous compounds are described in GB-A- 907356.

The most preferred bleach activator is TAED.

Another preferred class of bleach activators are the amide substituted compounds disclosed in Wa 94/03553 ather bleach activators include sodium nonanoyloxy benzene sulfonate, sodium trimethyl hexanoyloxy benzene sulfonate, sodium acetoxy benzene sulfonate and sodium benzoyloxy benzene sulfonate as disclosed in, for example, EP-A-0341 947.

The bleach activator may be present in any suitable amount. In one aspect the bleach activator is present in an amount of 0.2-3.0 wt% based on the washing composition. More preferably the bleach activator is present in an amount of 0.4-2.5 wt%, preferably in an amount of 0.5-2.2 wt%, preferably in an amount of 0.5-2.0 wt%, preferably in an amount of 0.8-2.0 wt%, preferably in an amount of 1.0-2.0 wt%, preferably in an amount of 1.2-2.0 wt%, preferably in an amount of 1.4-2.0 wt%, preferably in an amount of 1.6-2.0 wt%, preferably in an amount of 1.7-1.9 wt%, preferably in an amount of approximately 1.8 wt% based on the washing composition.

In one aspect the peroxygen bleach and the bleach activator are present in amounts such that in the absence of the EDDS bleaching of the bleach sensitive dyed fabric would occur.

Fabric/Bleach Sensitive In one aspect the fabric is dyed predominantly with or only with a bleach sensitive dye. In this aspect the present invention is particularly advantageous as the invention allows for washing of the fabric with a bleach which would otherwise be detrimental to the colour of the fabric. Until now fabrics dyed predominantly with or only with a bleach sensitive dyes could not be effectively washed with a bleaching detergent without unacceptable loss of colour.

In one preferred aspect the fabric is dyed only with a bleach sensitive dye. This aspect offers yet further advantages. Previously it had been possible to dye materials with bleach sensitive and bleach insensitive dyes. If the bleach sensitive dye were to be bleached and to lose its colour this colour loss would be masked by the colour of the bleach insensitive dye. The present invention allows for washing of fabrics dyed only with bleach sensitive dyes. Alternatively the invention avoids the need to dye with both bleach sensitive and bleach insensitive dyes.

In one preferred aspect the fabric is dyed with a bleach sensitive dye and bleach insensitive dye. This aspect offers further advantages. Previously on washing materials dyed with bleach sensitive and bleach insensitive dyes, the bleach sensitive dye would lose colour. This would result is loss of the strength of colour (i.e. fading) if the bleach sensitive dye and bleach insensitive dye were of the same colour. However if the bleach sensitive dye and bleach insensitive dye were of different colours, fading of the bleach sensitive dye would result in change of shade of the fabric. For example a brown colour may be provided by a black bleach sensitive dye and a red bleach insensitive dye. Fading of the black bleach sensitive dye would result in fabric turning from brown to red. The present invention allows for washing of fabrics dyed combinations of bleach sensitive dye and a bleach insensitive dyes without fading or change of shade.

In one aspect the bleach sensitive dye is a reactive dye. By the term "reactive dye" it is meant a dye having a reactive site on the dye molecule that reacts with a functional group on a fibre of a fabric to bind the dye covalently under the influence of heat and pH.

Such dyes are commonly based on azo, metallized azo, anthraquinone, phthalocyanine and metal-complex formazon derivatives. The reactive site in the dyes include either a mobile leaving group or a polarizable double bond In one aspect the bleach sensitive dye is selected from the bleach sensitive dyes listed in BS EN ISO 105-C092003.

In one aspect the fabric is dyed predominantly with or only with a bleach sensitive dye selected from the bleach sensitive dyes listed in BS EN ISO 105-C09:2003. Th

In a preferred aspect the fabric is dyed only with a bleach sensitive dye selected from the bleach sensitive dyes listed in BS EN ISO 105-C092003.

In one aspect the bleach sensitive dye is selected from Sulphur Black 1 (AISE 1), Reactive Black 5 (AISE 20), Reactive Orange 16 (AISE 22), Reactive dye trichromat (Brown/grey) (AISE 29), and Azoic combination (Orange) (AISE 7).

In one aspect the fabric is dyed predominantly with or only with a bleach sensitive dye selected from Sulphur Black I (AISE 1), Reactive Black 5 (AISE 20), Reactive Orange 16 (AISE 22), Reactive dye trichromat (Brown/grey) (AISE 29), and Azoic combination (Orange) (AISE 7).

In a preferred aspect the fabric is dyed only with a bleach sensitive dye selected from Sulphur Black I (AISE 1), Reactive Black 5 (AISE 20), Reactive Orange 16 (AISE 22), Reactive dye trichromat (Brown/grey) (AISE 29), and Azoic combination (Orange) (AISE 7).

AISE numbers refer to those accorded by the International Association for Soaps, Detergents and Maintenance Products (AISE).

Washing Suitable washing periods and temperatures could be ascertained by one skilled in the art.

In one aspect the washing composition is contacted with the fabric for a period of at least minutes, such as 20 minutes, 30 minutes, 40 minutes, or 50 minutes.

In one aspect the washing composition is contacted with the fabric at a temperature of at least 30 C, such as at least 40 C, at least 50 C, or at least 60 C.

The present invention will now be described in further detail by way of example only with reference to the accompanying figures in which:- Figure 1 is a graph; Figure 2 is a graph; Figure 3 is a photo; Figure 4 is a graph; Figure 5 is a graph; Figure 6 is a photo; Figure 7 is a photo; Figure 8 is a photo; Figure 9 is a photo; and Figure 10 is a photo.

The process of this invention is illustrated by the following Examples. In each of the examples "EDDS" means (S,S)-ethylenediaminedisuccinic acid, i.e. a compound of formula:

OH

OH HNkOH

H

EXAMPLES

Example 1. Dye Damage testing in hydrogen peroxide based systems in Tap water Standard test cloths 10cm2 of the appropriate bleach sensitive dyes (as supplied by University of Manchester, Textile Department) were prepared. The list of dyes and concentrations are shown in Table 1.

Table 1. Dye set used Dye Wt% Property Sulphur Black 1 (AISE 1) 4 Bleach Sensitive Reactive Black 5 (pale shade) (AISE 20) 1 Bleach Sensitive Reactive Orange 16 (AISE 22) 4 Bleach Sensitive Reactive Blue 71 4 Control Dye Wt% Property Reactive Violet 5 3 Chelate Sensitive Reactive Red 123 4 Metal Sensitive (Cu) Reactive Yellow 135 4 Metal Sensitive (Cu) 1450m1 of standard tap water (typical composition:- 40ppm Ca, 9ppm, Mg, <1 ppm Fe, I ppm <Cu, <1 ppm Ni and <lppm Mn) was heated in a 5L glass beaker to 40 C. To the water 50m1 of 30 wt% hydrogen peroxide (Fisher) was added and the temperature allowed to stabilise at 40 C. To these mixtures the appropriate chelate solutions were added to give equal molar concentrations. The chelates employed are listed in Table 2 with the concentrations used EDDS - as supplied by Associated Octel DTPMP - as supplied by Solutia under the name Dequest 2066 IDS - is iminodisuccinic acid as supplied by Bayer under the name Baypure CX100 MGDA - is methylglycine diacetic acid a supplied by BASF under the name Trilon M. The pH was adjusted to 10 using 20% sodium hydroxide solution.

Table 2. Experiment Conditions Experiment Chelate Mass added (g) I No Chelate n/a 2 EDDS 0.01 875 3 DTPMP 0.00625 4 MGDA 0.00436 IDS 0.00630 The tests cloths were added to the beaker and agitated at 150rpm for 1 hour. The cloths were removed and rinsed in tap water for 15 minutes before being dried for 6 hours at 40 C in fan oven.

The cloth's colour and brightness were measured using a flash photometer (Minolta DP- 301). The difference in brightness (L space) was compared to the original sample of cloth No Chelate EDDS DTPMP IDS MGDA Sulphur Black 1 (AISE 1) 13.74 7.67 13.43 16.40 13.48 Reactive Black 5 (AISE 20) 3.02 0 93 2.38 3.75 2.80 Reactive Orange 16 (AISE22) -1.33 0.12 -1.91 -2.86 -1.87 Reactive Blue 71 -0.28 -0.79 -1.94 - 1.31 -209 Reactive Violet5 2.10 1.15 1.61 1.98 1.55 Reactive Red 123 -2 74 -2.67 -3.52 -5.52 -5.22 Reactive Yellow 135 -5.13 -1.68 -6.76 -7.69 -6. 60 The data are also represented graphically in Figures 1 to 3.

Example 2. Testing in per-acetic acid based systems using a modified C09 Test The effect, of incorporating each chelant into a detergent formulation, on the oxidative- bleach fading of a series of dyed substrates has been studied, using the BS EN ISO 105-C09:2003 test. This test has been designed to predict the fading that a dyed substrate might experience after multiple machine launderings (see Journal of Society of Dyers and Colourists, Vol. 12, 1996, p.287).

When carrying out the standard BS EN ISO 105-C09:2003 test, a standard detergent base is used, which contain 0.8% (by weight) of Dequest 2066. Dequest 2066 is diethylene triamine pentamethyl phosphonic acid (DTPMP) a phosphonate To this is added the sodium perborate and TAED. For the purpose of this evaluation an alternative detergent base was provided without any chelant and to which known quantities of either Dequest 2066 (DTPMP) or EDDS could be added.

The test was carried out using the sample test cloths as in Example 1. To the de-ionised water, 10 wt% of the chelant free detergent base, 12 wt% Sodium Perborate and 1.8 wt% TAED were added. The liquor ratio was 100:1 The appropriate chelant was added as well as lppm Cu ions and lOOppm Ca ions. DTPMP (Dequest 2006) was used at 0.4%, 0.2% and 0.1% weight on detergent and EDDS (Octaquest E30) at 0.2%, 0.1% and 0.05%.

The fabric cloths were added and heated to 60 C over 20 minutes with stirring. The mixture was held at 60 C for 30 minutes. The cloths were removed from wash and rinsed in cold water. The brightness and colour of the cloths were again measured using a flash photometer.

The results obtained are shown in Figures 4 to 10. The flash photometer readings are provided below.

Chelant Concentration Test No. A Reactive Black 5 (AISE 20) DE* DL* 0.4% Dequest 2 10.14 6.48 0.2% Dequest 3 10.12 6.34 0.1% Dequest 4 6.96 4.23 0.2% Octaquest 5 1.64 0.78 0.1% Octaquest 6 1.59 0.64 0.05% Octaquest 7 1.75 0.98 0.1%Dequest 8 855 549 0.05% Octaquest ________________ _______________ _______________ Chelant Concentration Test No. B Sulphur Black 1 (AISE 1) DE* DL* 0.4% Dequest 2 17.62 17.51 0.2% Dequest 3 17.20 17.09 0.1%Dequest 4 14.26 14.17 0 2% Octaquest 5 8.93 8.86 0.1% Octaquest 6 8.30 8.23 0 05% Octaquest 7 8.20 8.13 0.1%Dequest 8 1675 1664 0.05% Octaquest ________________ _______________ _______________ Chelant Concentration Test No. C Reactive Orange 16 (AISE 22) DE* DLE* 0.4% Dequest 2 13.31 7.64 0.2%Dequest 3 12.79 7.37 0.1%Dequest 4 8.84 4.90 0.2% Octaquest 5 2.38 0.58 0.1% Octaquest 6 2.03 0.63 0.05% Octaquest 7 1.71 0.67 0.1%Dequest 8 1255 665 0.05% Octaquest ________________ ________________ ________________ Chelant Concentration Test No. D Reactive Violet 5 DE* DLE* 0.4% Dequest 2 3.76 3.64 0.2% Dequest 3 3.16 3.09 0.1% Dequest 4 2.09 2.09 0.2% Octaquest 5 1.55 1.55 0.1%Octaquest 6 1.41 1.41 0.05% Octaquest 7 1.70 1.69 0.1%Dequest 8 292 284 0.05% Octaquest ________________ _______________ _______________

___________________________________________ __________________________

Chelant Concentration Test No. E Reactive Yellow 135 DE* DLE* 0.4% Dequest 2 4.62 1.32 0.2%Dequest 3 4.38 1.11 0.1%Dequest 4 6.00 -1.22 0.2% Octaquest 5 3.92 -0.87 0.1%Octaquest 6 4.71 -1.36 0.05% Octaquest 7 6.76 -2.20 0.1%Dequest 8 519 -019 0.05% Octaquest.

Chelant Concentration Test No. F Reactive Red 123 DE* DLE* 0.4%Dequest 2 1.96 0.21 0.2% Dequest 3 2.77 -0.36 0.1%Dequest 4 4.66 -1.28 0.2% Octaquest 5 3.60 -0.86 0 1% Octaquest 6 3.22 -0.68 0.05% Octaquest 7 3.47 -0.66 0.1%Dequest 8 376 085 0.05% Octaquest. - Notes 1) Illuminant = D65 100 2) Positive DL* values indicate shade is lighter than the original, negative DL* values indicate shade is darker than the original.

3) All tests carried out in the presence of 1 ppm Cu2+ and 100 ppm Ca2+ All publications mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described methods and system of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in chemistry or related fields are intended to be within the scope of the following claims.

Claims (1)

1. A process for washing a fabric dyed with a bleach sensitive dye, said process comprising contacting the bleach sensitive dyed fabric with a washing composition comprising (i) ethylenediaminedisuccinic acid (EDDS) or a salt thereof (ii) a peroxygen bleach; and optionally (iii) a bleach activator.

2. A process according to claim 1 comprising a bleach activator.

3. A process according to claim 1 or 2 wherein the EDDS is (S,S)ethylenediaminedisuccinic acid or a salt thereof.

4. A process according to claim 1, 2 or 3 wherein the EDDS comprises at least 70 wt% of chelating agents present in the washing composition based on the content of chelating agents.

5. A process according to any one of the preceding claims wherein the EDDS comprises at least 90 wt% of chelating agents present in the washing composition based on the content of chelating agents.

6. A process according to any one of the preceding claims wherein the washing composition is substantially free of phosphonate chelating agents.

7. A process according to any one of the preceding claims wherein the washing composition is substantially free of chelating agents other than EDDS.

8. A process according to any one of the preceding claims wherein the EDDS is present in an amount of at least 0.1 wt% based on the washing composition.

9. A process according to any one of the preceding claims wherein the EDDS is present in an amount of at least 0.2 wt% based on the washing composition.

10. A process according to any one of the preceding claims wherein the EDDS is present in an amount of at least 0.4 wt% based on the washing composition.

11. A process according to any one of the preceding claims wherein the peroxygen bleach is a hydrogen peroxide.

12 A process according to any one of the preceding claims wherein the peroxygen bleach is a percarbonate.

13 A process according to any one of the preceding claims wherein the peroxygen bleach is present in an amount of 5-20 wt% based on the washing composition.

14. A process according to any one of the preceding claims wherein the bleach activator is tetra acetyl ethylene diamine (TAED).

15. A process according to any one of the preceding claims wherein the bleach activator is present in an amount of 0.2-3.0 wt% based on the washing composition.

16. A process according to any one of the preceding claims wherein the fabric is dyed predominantly with or only with a bleach sensitive dye.

17 A process according to any one of the preceding claims wherein the fabric is dyed only with a bleach sensitive dye.

18. A process according to any one of the preceding claims wherein the bleach sensitive dye is selected from Sulphur Black 1 (AISE 1), Reactive Black 5 (AISE 20), Reactive Orange 16 (AISE 22), Reactive dye trichromat (Brown/grey) (AISE 29), and Azoic combination (Orange) (AISE 7).

19. A process according to any one of the preceding claims wherein the peroxygen bleach and the bleach activator are present in amounts such that in the absence of the EDDS bleaching of the bleach sensitive dyed fabric would occur.

20. A process according to any one of the preceding claims wherein the washing composition is contacted with the fabric for a period of at least 20 minutes.

21. A process according to any one of the preceding claims wherein the washing composition is contacted with the fabric at a temperature of at least 50 C.

22. Use of ethylenediaminedisuccinic acid (EDDS) or a salt thereof for preventing or reducing bleaching of a fabric dyed with a bleach sensitive dye by a bleach.

23. Use according to claim 22 wherein the bleach is a component of a washing composition.

24. Use according to claim 23 wherein the washing composition comprises a bleach activator.

25. Use according to claim 22, 23 or 24 wherein the bleach is a peroxygen bleach.

26. Use according to any one of claims 22 to 25 characterised by the features of any one of claims 2 to 21.

27. A detergent composition comprising (i) ethylenediaminedisuccinic acid (EDDS) or a salt thereof (ii) a peroxygen bleach; and optionally (iii) a bleach activator.

28. A detergent composition according to claim 27 characterised by the features of any one of claims 2 to 21.

29. A process as substantially described herein with reference to any one of the

Examples

32. A use as substantially described herein with reference to any one of the Examples.

31. A composition as substantially described herein with reference to any one of the

Examples.