WO2002050228A1

WO2002050228A1 - Stain treatment composition

Info

Publication number: WO2002050228A1
Application number: PCT/EP2001/012345
Authority: WO
Inventors: Stephen Norman Batchelor; Neil Jones
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2000-12-19
Filing date: 2001-10-24
Publication date: 2002-06-27
Also published as: GB0030956D0; AU2002221748A1

Abstract

The invention is based on the finding that a mixture of long and short chain DTI polymers gives improved removal of dyes from fabrics. It provides a fabric treatment composition which comprises one or more dye transfer inhibiting polymers, wherein the overall distribution of the molecular weight of said polymers is polymodal and whereby the composition is effective both at scavenging a dye from a fabric and at preventing redeposition of said dye. The present invention also extends to methods for treatment of fabrics which comprise treating the fabric with a composition according to the present invention. Preferred materials for the DTI polymer in either weight range include poly (ethylene glycol) (PEG), poly(vinyl pyridine carboxyl methyl betaine) (PVPCMB), poly(vinyl pyrrolidone) (PVP), N-oxide modified PVP (PVP-NO).

Description

STAIN TREATMENT COMPOSITION

Technical Field

The present invention provides a composition and a method for the treatment of stains. More particularly, the invention relates to the treatment of stains on fabrics which have been caused by dye transfer.

Background of the Invention

Dye transfer is a familiar problem in fabric laundering. It occurs most commonly when a lightly-coloured garment is washed together with a strongly coloured garment which contains a 'non-fast' dye.

Typically, dye is released from the strongly coloured garment during the washing process and transfers onto the lightly coloured garment bringing about a change of colour in that garment . As dyes are substantive to textile fibres removal of the dye from the lightly coloured garment can be difficult, particularly if the lightly coloured garment and the dyestuff have a high affinity for each other.

Dye transfer may occur over the whole of an article or may simply occur over parts of it . The latter problem can occur when wet coloured articles are left in contact with light or non-coloured articles. Related problems occur when localised staining of an article occurs with a dyestuff such as when the cap of a pen becomes detached in a pocket and leakage of ink into fabric occurs .

Previous solutions to this problem have involved treating the lightly coloured garment with a dilute bleach solution. However this is a chemically harsh process and can damage some fabrics .

A more modern approach to dye transfer in washing machines has been to prevent dye transfer before it occurs. Dye transfer inhibitors are known in the laundry art . Typically these materials function in one of two ways. Some inhibitors are effective at bleaching any dyestuff which comes into solution thus preventing its redeposition in a coloured form. Other inhibitors simply bind with the dye to prevent redeposition on the fabric surface: the complex of inhibitor and dye is then removed during rinsing. Despite these advances, incidents of dye transfer still occur when white and coloured garments are washed together under conditions which promote dye transfer.

Similar techniques to those used to prevent the redeposition of dyes have been used to prevent soil redeposition. Indeed, the function of surfactants in the wash is largely to prevent redeposition of soil which has been removed from the articles being washed by mechanical action. Other non- surfactant materials used to prevent the re-deposition of soils and dyes by a complex-forming route have included poly (ethylene glycol) , poly (vinyl pyridine carboxyl methyl betaine) and poly (vinyl pyrrolidone) . In the present specification these and similar, non-surfactant polymers which share the functionality of preventing soil or dye transfer are known in the art as dye transfer inhibiting or DTI' polymers.

Brief Description of the Invention

The present invention is based on the finding that a mixture of long and short chain DTI polymers gives improved removal of dyes from fabrics .

The penetrative ability of polymers in labyrinthine spaces is party described by the well-known Einstein viscosity equation [n] = k (v/m) , where [n] is the limiting viscosity index, k is a constant, v is the hydrodynamic volume and m is the molecular weight of the polymer. For many polymers m. [n] plotted against elution volume give a relatively straight line (see Polymer Letters Vol. 5 pp. 753-759 (1967) ) .

Accordingly, the present invention provides a fabric treatment composition which comprises one or more dye transfer inhibiting polymers, wherein the overall distribution of the molecular weight of said polymers is polymodal and whereby the composition is effective both at scavenging a dye from a fabric and at preventing redeposition of said dye. In a further aspect, the present invention provides a fabric treatment composition which comprises one or more dye transfer inhibiting polymers, wherein one of the polymers is such that the product of limiting viscosity (in cm³gm^"1) and molecular weight (in Daltons) is greater than 1000 and the other polymer has a corresponding product of less than 1000.

While it is not intended to restrict the scope of the invention by reference to any theory of operation, it is believed that longer-chain polymers are more effective at holding dyes in solution, while shorter chain polymers are effective at penetrating fabric and scavenging dye molecules from the fabric. Thus, in the invention, the shorter chain DTI polymers will effectively act as a shuttle' system to scavenge and transfer the dye from the fabric to the longer chain polymer which then prevents its redeposition by binding to the dye and holding it in solution.

It is believed that this is reflected in the product of viscosity and molecular weight by virtue of the relationship discussed above, such that for typical fabrics such as cotton and other cellulosics (i.e. those materials which are prone to staining) , DTI polymers falling within the required ranges of [n] .m >1000 and [n] .m < 1000 will have the required balance of properties.

The present invention also extends to methods for treatment of fabrics which comprise treating the fabric with a composition according to the present invention. Detailed Description of the Invention

By 'polymodal' is meant that the population of DTI polymers present in the composition does not exhibit a single, relatively sharp, molecular weight peak. Preferably, the compositions contain discrete populations of low molecular weight materials which are effective at scavenging and transporting dye and higher molecular weight materials which are effective at holding dye in solution or suspension. The composition could also comprise a continuous population which contained both the low and the high molecular weight materials, although for practical reasons it is preferred that the composition comprise a mixture of two or more polymers of differing mean molecular weights. Compositions having a bimodal distribution of molecular weights are preferred.

Polymer materials:

Preferred materials for the DTI polymer in either weight range include poly (ethylene glycol) ('PEG'), poly (vinyl pyridine carboxyl methyl betaine) ('PVPCMB), poly (vinyl pyrrolidone) ('PVP'), N-oxide modified PVP ('PVP-NO').

The polymers of the low and high molecular weight type can be of the same molecular type or can differ. It is preferred that each is of the same molecular type (such as both are PVP) , although the use of mixtures of two or more different types of polymers (such as PEG/PVP or PVP/PVPCMB) is not excluded. Suitable combinations include PEG600 (where 600 is the mean molecular weight) together with PEG20000.

Preferably at least one peak in the molecular weight distribution is below 100,000 and at least one peak is above 100,000.

Preferably, at least one molecular weight peak is in the range 500-50,000, more preferably 3500-40,000. Suitable materials having mean molecular weights in this range include PVP10000; PEG600; PVP3500; and PVPCMB40000

Preferably at least one molecular weight peak is in the range 100,000-10,000,000, more preferably 100,000-500,000. Suitable materials having mean molecular weights in this range include PVP360000 and PVPCMB140000.

Preferred combinations include PVP10000 with PVP360000; PEG600 with PVP360000; PVP3500 with PVP360000; PVPCMB40000 with PVP360000 and PVP3500 with PVPCMB140000.

Preferably the ration of the high molecular weight to the low molecular weight polymer falls in the range 1:4 to 4:1, more preferably 1:2 to 2:1.

While some compositions exhibit synergy in that the overall dye removal effect of mixtures is better than that would be expected by simply taking the ratio of the effects of the polymers present, preferred compositions are those in which the effect of the mixture of polymers is better than that of either of the components taken alone. Preferably, the compositions are applied to the articles being treated in the form of an aqueous liquor. Typical levels of polymer in the compositions of the invention are such that the in-use concentration of the polymer in the treatment liquor is 0.01-l%wt for each of the low and high molecular weight polymers .

The compositions of the invention may be used before, during or after a conventional laundry process and are preferably packaged and labelled as such. The laundry process includes large and small scale processes, and is preferably a domestic process.

It is preferable that the compositions are packaged and presented in a manner suitable for occasional use rather than being used systematically as a part of a normal laundering process . Consequently, the compositions would be used for the laundering of garments or other articles which had become coloured due to dye transfer, the intention being to largely or wholly restore the initial appearance of the articles. In addition to utility in treating whole articles the compositions of the invention may be used in localised or 'spot' treatment of stains. However, use of the compositions of the invention as components of a regular-use laundry detergent composition is not excluded.

When the compositions of the invention are to be used before or after the laundry process, they may be in the form of a spray or foaming product. Conveniently, this may be applied directly to a stained or coloured area. When the compositions of the invention are to be used during the laundry process, they may be used at any convenient stage of the process, such as, for example, in a pre-wash composition, in the main wash detergent composition and/or a rinse composition.

Compositions according to the invention preferably comprise a textile compatible carrier.

In the context of the present invention the term 'textile compatible carrier' means a component which can assist in the interaction of the polymers with the fabric. The carrier can also provide benefits in addition to those provided by the polymer e.g. softening, cleaning etc. The nature of the carrier will depend upon at what stage of the laundry process the composition of the invention is used. The carrier may be water or a detergent-active compound or a fabric softener or conditioning compound or other suitable detergent or fabric treatment agent .

If the composition of the invention is to be used in a laundry process as part of a conventional fabric treatment product, such as a detergent composition, the textile- compatible carrier will typically be a detergent-active compound. Whereas, if the fabric treatment product is a rinse conditioner, the textile-compatible carrier will be a fabric softening and/or conditioning compound. Detergent Active Compounds :

If the composition of the present invention is in the form of a detergent composition (such as a main wash composition) , the textile-compatible carrier may be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric and zwitterionic detergent active compounds, and mixtures thereof.

Many suitable detergent active compounds are available and are fully described in the literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch.

The preferred textile-compatible carriers that can be used are soaps and synthetic non-soap anionic and nonionic compounds .

Anionic surfactants are well-known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of C₈-Cι₅; primary and secondary alkyl sulphates, particularly C₈-Cι₅ primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.

Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C₈-C₂o aliphatic alcohols ethoxylated with an average of from 1 to

20 moles of ethylene oxide per mole of alcohol, and more especially the Cι₀-Cι₅ primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non-ethoxylated nonionic surfactants include alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide) .

Cationic surfactants that may be used include quaternary ammonium salts of the general formula RιR₂R₃R₄-\.⁺ X^" wherein the R groups are independently hydrocarbyl chains of C1-C2₂ length, typically alkyl, hydroxyalkyl or ethoxylated alkyl groups, and X is a solubilising anion (for example, compounds in which Ri is a C₈-C₂₂ alkyl group, preferably a C₈-Cιo or Ci₂-C₁₄ alkyl group, R₂ is a methyl group, and R₃ and R₄, which may be the same or different, are methyl or hydroxyethyl groups) ; and cationic esters (for example, choline esters) and pyridinium salts.

The total quantity of detergent surfactant in the composition is suitably from 0.1 to 60 wt%, e.g. 0.5-55 wt%, such as 5-50 wt%.

Preferably, the quantity of anionic surfactant (when present) is in the range of from 1 to 50% by weight of the total composition. More preferably, the quantity of anionic surfactant is in the range of from 3 to 55% by weight, e.g. 5 to 30% by weight.

Preferably, the quantity of anionic surfactant is in the range of from 3 to 35% by weight, e.g. 5 to 30% by weight. Preferably, the quantity of nonionic surfactant when present is in the range of from 2 to 25% by weight, more preferably from 5 to 20% by weight.

Amphoteric surfactants may also be used, for example amine oxides or betaines .

The compositions may suitably contain from 10 to 70%, preferably from 15 to 70% by weight, of detergency builder. Preferably, the quantity of builder is in the range of from 15 to 50% by weight.

The detergent composition may contain as builder a crystalline aluminosilicate, preferably an alkali metal aluminosilicate, more preferably a sodium aluminosilicate.

The aluminosilicate may generally be incorporated in amounts of from 10 to 70% by weight (anhydrous basis) , preferably from 25 to 50%. Aluminosilicates are materials having the general formula:

0.8-1.5 M₂0 A1₂0₃. 0.8-6 Si0₂

where M is a monovalent cation, preferably sodium. These materials contain some bound water and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 Si0₂ units in the formula above. They can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature. Fabric Softening and/or Conditioner Compounds:

The compositions of the invention may be in the form of a rinse composition, such as a fabric conditioner composition.

If the fabric care composition or the laundry rinse composition of the present invention is in the form of a fabric conditioner composition, the textile-compatible carrier will be a fabric softening and/or conditioning compound (hereinafter referred to as "fabric softening compound"), which may be a cationic or nonionic compound.

The softening and/or conditioning compounds may be water insoluble, non-polymeric, quaternary ammonium compounds. The compounds may be present in amounts of up to 8% by weight (based on the total amount of the composition) in which case the compositions are considered dilute, or at levels from 8% to about 50% by weight, in which case the compositions are considered concentrates.

Compositions suitable for delivery during the rinse cycle may also be delivered to the fabric in the tumble dryer if used in a suitable form. Thus, another product form is a composition (for example, a paste) suitable for coating onto, and delivery from, a substrate e.g. a flexible sheet or sponge or a suitable dispenser (such as a container having apertures therein, for example) during a tumble dryer cycle.

Suitable cationic fabric softening compounds are substantially water-insoluble quaternary ammonium materials comprising a single alkyl or alkenyl long chain having an average chain length greater than or equal to C₂o or, more preferably, compounds comprising a polar head group and two alkyl or alkenyl chains having an average chain length greater than or equal to C₁₄. Preferably the fabric softening compounds have two long chain alkyl or alkenyl chains each having an average chain length greater than or equal to Cι₆. Most preferably at least 50% of the long chain alkyl or alkenyl groups have a chain length of Cι₈ or above. It is preferred if the long chain alkyl or alkenyl groups of the fabric softening compound are predominantly linear.

Quaternary ammonium compounds having two long-chain aliphatic groups, for example distearyldimethyl ammonium chloride and di (hardened tallow alkyl) dimethyl ammonium chloride, are widely used in commercially available rinse conditioner compositions. Other examples of these cationic compounds are to be found in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch. Any of the conventional types of such compounds may be used in the compositions of the present invention.

The fabric softening compounds are preferably compounds that provide excellent softening, and are characterised by a chain melting Lβ to Lα transition temperature greater than 25 °C, preferably greater than 35 °C, most preferably greater than 45 °C. This Lβ to Lα transition can be measured by DSC as defined in "Handbook of Lipid Bilayers" , D Marsh, CRC Press, Boca Raton, Florida, 1990 (pages 137 and 337) . Substantially water-insoluble fabric softening compounds are defined as fabric softening compounds having a solubility of less than 1 x 10^"3 wt % in demineralised water at 20°C. Preferably the fabric softening compounds have a solubility of less than 1 x 10^"4 wt %, more preferably less than 1 x 10^"

Especially preferred are cationic fabric softening compounds that are water-insoluble quaternary ammonium materials having two C₁₂-₂₂ alkyl or alkenyl groups connected to the molecule via at least one ester link, preferably two ester links. An especially preferred ester-linked quaternary ammonium material can be represented by the formula II:

(CH2)p-T-R₂

wherein each Ri group is independently selected from Cι_ alkyl or hydroxyalkyl groups or C₂- alkenyl groups ; each R₂ group is independently selected from C₈.₂₈ alkyl or alkenyl groups ; and wherein -R₃- is a linear or branched alkylene group of 1 to 5 carbon atoms , T is

0 O

11 11

-O-C- or -C-0-;

and p is 0 or is an integer from 1 to 5 Di (tallowoyloxyethyl) dimethyl ammonium chloride and/or its hardened tallow analogue is especially preferred of the compounds of formula (II) .

A second preferred type of quaternary ammonium material can be represented by the formula (III) :

wherein Ri, p and R₂ are as defined above.

It is advantageous if the quaternary ammonium material is biologically biodegradable.

Preferred materials of this class such as 1,2 -bis (hardened tallowoyloxy) -3-trimethylammonium propane chloride and their methods of preparation are, for example, described in US 4 137 180 (Lever Brothers Co) . Preferably these materials comprise small amounts of the corresponding mono- ester as described in US 4 137 180, for example, 1-hardened tallowoyloxy-2-hydroxy-3-trimethylammonium propane chloride,

Other useful cationic softening agents are alkyl pyridinium salts and substituted imidazoline species. Also useful are primary, secondary and tertiary amines. The compositions may alternatively or additionally contain water-soluble cationic fabric softeners, as described in GB 2 039 556B (Unilever) .

The compositions may comprise a cationic fabric softening compound and an oil, for example as disclosed in EP-A-0829531.

The compositions may alternatively or additionally contain nonionic fabric softening agents such as lanolin and derivatives thereof.

Lecithins are also suitable softening compounds.

Nonionic softeners include Lβ phase forming sugar esters (as described in M Hato et al Langmuir 12, 1659, 1966, (1996) ) and related materials such as glycerol mono-stearate or sorbitan esters. Often these materials are used in conjunction with cationic materials to assist deposition (see, for example, GB 2 202 244 ) . Silicones are used in a similar way as a co-softener with a cationic softener in rinse treatments (see, for example, GB 1 549 180) .

The compositions may also suitably contain a nonionic stabilising agent. Suitable nonionic stabilising agents are linear C₈ to C₂₂ alcohols alkoxylated with 10 to 20 moles of alkylene oxide, Cι₀ to C₂o alcohols, or mixtures thereof. Advantageously the nonionic stabilising agent is a linear C₈ to C₂₂ alcohol alkoxylated with 10 to 20 moles of alkylene oxide. Preferably, the level of nonionic stabiliser is within the range from 0.1 to 10% by weight, more preferably from 0.5 to 5% by weight, most preferably from 1 to 4% by weight. The mole ratio of the quaternary ammonium compound and/or other cationic softening agent to the nonionic stabilising agent is suitably within the range from 40:1 to about 1:1, preferably within the range from 18:1 to about 3:1.

The composition can also contain fatty acids, for example C₈ to C₂₄ alkyl or alkenyl mono-carboxylic acids or polymers thereof. Preferably saturated fatty acids are used, in particular hardened tallow C₁₆ to C₁₈ fatty acids. Preferably the fatty acid is non-saponified, more preferably the fatty acid is free, for example oleic acid, lauric acid or tallow fatty acid. The level of fatty acid material is preferably more than 0.1% by weight, more preferably more than 0.2% by weight. Concentrated compositions may comprise from 0.5 to 20% by weight of fatty acid, more preferably 1% to 10% by weight. The weight ratio of quaternary ammonium material or other cationic softening agent to fatty acid material is preferably from 10:1 to 1:10.

The fabric conditioning compositions may include silicones, such as predominantly linear polydialkylsiloxanes, e.g. polydimethylsiloxanes or aminosilicones containing amine- functionalised side chains; amphoteric surfactants; smectite type inorganic clays; zwitterionic quaternary ammonium compounds; and nonionic surfactants. Preferably, the silicone component is a dimethylpolysiloxane with amino- alkyl groups . The fabric conditioning compositions may also include an agent which produces a pearlescent appearance, e.g. an organic pearlising compound such as ethylene glycol distearate, or inorganic pearlising pigments such as microfine mica or titanium dioxide (Ti0₂) coated mica.

The fabric conditioning compositions may be in the form of emulsions or emulsion precursors thereof.

Other optional ingredients include emulsifiers, electrolytes (for example, sodium chloride or calcium chloride) preferably in the range from 0.01 to 5% by weight, pH buffering agents, and perfumes (preferably from 0.1 to 5% by weight) .

Further optional ingredients include one or more of non- aqueous solvent, perfume carriers, fluorescers, colourants, hydrotropes, antifoaming agents, enzymes, optical brightening agents, opacifiers, anti-shrinking agents, anti- wrinkle agents, anti-spotting agents, germicides, fungicides, anti-oxidants , UV absorbers (sunscreens), heavy metal sequestrants, chlorine scavengers, dye fixatives, anti-corrosion agents, drape imparting agents, antistatic agents and ironing aids. This list is not intended to be exhaustive.

Fabric Treatment Products :

The composition of the invention may be in the form of a liquid, solid (e.g. powder or tablet), a gel or paste, spray, stick or a foam or mousse. Examples include a soaking product, a rinse treatment (e.g. conditioner or finisher) or a main-wash product. The composition may also be applied to a substrate (e.g. a flexible sheet) or used in a dispenser which can be used in the wash cycle or the rinse cycle.

The fabrics which may be treated in the present invention may be in the form of garments and preferably comprise cellulosic fibres, preferably from 1% to 100% cellulosic fibres (more preferably 5% to 100% cellulosic fibres, most preferably 40% to 100% such as 75% to 100%) . When the fabric contains less than 100% cellulosic fibres, the balance comprises other fibres or blends of fibres suitable for use in garments such as polyester or polyamide, for example. Preferably, the cellulosic fibres are of cotton or regenerated cellulose such as viscose.

The invention will now be described by way of example only and with reference to the following non-limiting examples.

Examples

Cotton that had been dyed with Direct Green 26 to a level of 5% on weight of fabric was soaked in hot water to prepare a solution of dye for dye transfer. White mercerised cotton was subjected to dye transfer by immersion in the resultant solution.

The dyed cotton was removed from the solution and the excess solution removed by using a spin dyer. The cotton was thoroughly rinsed using cold deionised water and the excess water removed by spin dying. The cotton was allowed to dry at ambient temperature. The levels of dye transferred to the cotton were measured using a Datacolour International Spectraflash™ SF600.

Solutions of DTI polymer were made by dissolving the desired level of polymer in 50ml deionised water in a polythene bottle. The bottle was sealed, placed in a Gallenkamp™ shaker water bath and allowed to equilibrate to 40°C at 100 oscillations per minute. When the solution of the polymer solution had reached 40°C, four pieces each 5cm x 5cm (total weight 1.6g) was added to the bottle and the contents washed at 40°C for 30 minutes under agitation. The washed cloths were rinsed using deionised water and the excess water remover using a spin dyer. The fabric was allowed to dry at ambient temperature.

The level of dye in solution was determined using a Perkin Elmer™ UV/Vis spectrometer using deionised water as the reference. The level of direct green 26 in solution was determined at wavelength of 630nm and was normalised by subtracting the adsorbance measured at a wavelength of

800nm.

Similar methods were used for Direct Blue 71, at a different wavelength.

The amount of fading of the washed cloths was measured using a Datacolour International Spectraflash SF600. Results are quoted as dE. Example 1

Effect of poly (vinyl pyrrolidone) and poly (ethylene oxide) molecular weights on stripping direct green 26 dye from fabric. Examples using mixtures of polymer are shown in bold.

Table 1

*High dE represents a greater loss of dye from the fabric

From these results it can be seen that poly (ethylene glycol) , 'PEG' is less effective at stripping dyes from fabric than poly (vinyl pyrrolidone) , 'PVP' . However the combination of 0.5%PEG and 0.5%PVP gave levels of dye strip close to the parent PVP.

The results also show how a combination of low and high molecular weight polymer generally exhibits a synergistic dye stripping benefit .

Example 2

Effect of the combination of a low and high molecular weight poly (vinyl pyrrolidone) s on stripping Direct Green 26 from fabric .

Table 2

Example 2 demonstrates the effect of combining a low molecular weight PVP (3500) and a high molecular weight PVP (360000) . Combination in all cases increases the amount of dye released into solution from the fabric over the result obtained with the individual PVP's. Example 3

Effect of the combination of a low and high molecular weight poly (vinyl pyrrolidone) on dye stripping from fabric

Table 3

Examples 3 shows that combinations of PVP's gave higher levels of dye strip over what would be expected from either PVP.

Example 4

Table 4

This example again shows that the some benefit is obtained over the expected results of mere admixture. While the combination of the polymers is not as good as the low molecular weight PVP alone, the results of using the mixture are significantly closer to the results obtained with the low molecular weight PVP taken alone.

Example 5 : Other polymers .

This example uses DTI-1 2OB - poly (vinyl pyridine carboxyl methyl betaine) average molecular weight 140000 and DTI-1 20C - poly (vinyl pyridine carboxyl methyl betaine) average molecular weight 40000

Table 5

*A lower dE indicates that more dye has been stripped from the fabric . Example 5 shows the effect of PVP and poly (vinyl pyridine carboxyl methyl betaine) and combination of the level of dye stripping. It can be seen that for the second, third and fourth sub-examples the best results were obtained when the combination of polymers was used.

Example 6 :

Effect of the combination of a low and high molecular weight poly (vinyl pyrrolidone) on dye stripping (in this case Direct Blue 71) from fabric

Table 6

Examples 6 shows that combinations of PVP's gave higher levels of dye strip over what would be expected from either PVP.

Claims

1. A fabric treatment composition which comprises one or more dye transfer inhibiting polymers, wherein the overall distribution of the molecular weight of said polymers is polymodal, and whereby the composition is effective both at scavenging a dye from a fabric and at preventing redeposition of said dye.

2. A fabric treatment composition which comprises one or more dye transfer inhibiting polymers, wherein one of the polymers is such that the product of limiting viscosity (in cm³gm^"1) and molecular weight (in Daltons) is greater than 1000 and the other polymer has a corresponding product of less than 1000.

3. Composition according to Claim 1 or 2, wherein the dye transfer inhibiting polymer is selected from the group comprising poly (ethylene glycol, poly (vinyl pyridine carboxyl methyl betaine), poly (vinyl pyrrolidone),

N-oxide modified PVP ('PVP-NO'), and mixtures thereof.

4. Composition according to any preceding Claim, wherein at least one peak in the molecular weight distribution is below 100,000 and at least one peak is above 100, 000.

5. Composition according to any preceding Claim, comprising polymer with at least one molecular weight peak is in the range 500-50,000, preferably 3500-40, 000. - 21

6. Composition according to any preceding Claim, comprising polymer with at least one molecular weight peak is in the range 100,000-10,000,000, preferably 100,000-500,000.

7. Composition according to any preceding Claim, wherein the ratio of the high molecular weight to the low molecular weight polymer falls in the range 1:4 to 4:1, more preferably 1:2 to 2:1.

8. Composition according to any preceding Claim, comprising a surfactant.

9. Composition according to any preceding Claim, comprising a fabric softening and/or conditioning agent .

10. A fabric treatment method which comprises the step of contacting the fabric with a composition according to any one the preceding claims.

11. A method according to claim 10 wherein the in-use concentration of the polymer in a treatment liquor is 0.01-l%wt for each of the low and high molecular weight polymers .