The present invention relates to fabric care compositions, such as laundry detergent compositions and laundry rinse compositions, which comprise an oxazoline-ring functionalised material. The invention also relates to a method of treating fabric using the compositions of the invention and to the use of oxazoline-ring functionalised materials in the treatment of fabric which comprises oxidised cellulose to provide a colour care benefit to the fabric.

It is known that the laundry process is harsh to fabrics. Repeated wash and wear cycles produce the problems of progressive colour loss and mechanical damage to laundered fabrics.

A specific problem is oxidative damage to the fabrics, especially cotton based fabrics. Oxidising species are present in the laundering process due to the wide-ranging inclusion of oxidation sources (such as bleaches) in detergents, or oxidising species present in the water supply (such as chlorine based disinfectants added as part of the water treatment process).

Oxidising species are able to oxidise the hydroxyl groups present in cellulose to produce carboxylic acids/carboxylate groups. This is disadvantageous because cellulose oxidation leads to the weakening of the fibres in the cellulosic fabric, which in turns leads to pilling, fuzzing and/or fibrillation of the fabric and manifests as a fading of colour due to poorer light scattering from the fabric (see for example "The Kinetics of Cellulose Fibre Degradation and Correlation with some Tensile Properties", G. Testa, A. Sardella, E. Rossi, C. Bozzi, A. Seves, Acta Polymer 45 47-49 1994).

Cellulose oxidation also leads to enhanced complexation with transition metals such as copper, which catalyses further cellulose oxidation, and iron which causes yellowing of white fabrics (see "Catalytic Effects in the Alkaline Oxidation of Cellulose", W.A. Bell, Nature 186 963-964 18 June 1960 and "The Complexation of Fe(III)-ions in Cellulose Fibres: A Fundamental Property", A. Kongdee, T. Bechtold, Carbohydrate Polymers 56 2004 47-53).

Poly(2-ethyl-2-oxazoline) is known in the laundry field as a dye transfer inhibitor, i.e. in that it will bind to dye released during the laundry process to prevent the dye being transferred from one part of the fabric to another.

Examples in the art of such use of this material can be seen in US 6,525,013 and EP 0 668 902.

US 6,525,013 discloses fabric care and laundry detergent compositions which comprise low molecular weight modified and unmodified amines which provide enhanced fabric care benefits. The compositions may additionally comprise a polymer comprising poly(2-ethyl-2-oxazoline) for use as a fabric abrasion polymer and dye transfer inhibitor.

EP 0 668 902 relates to compositions and processes useful for inhibiting the transfer of dyes, released into laundering solution from coloured fabrics, from one fabric to another. Poly(2-ethyl-2-oxazoline is an example of one such material.

However, these poly(2-ethyl-2-oxazoline) materials lose their oxazoline ring functionality during polymerisation, so they do not comprise oxazoline in the form of a ring.

The present invention arises from the surprising finding that treatment of fabrics with an oxazoline material which is included in a polymer having at least two oxazoline-ring moieties provides a colour benefit to laundered fabrics.

Accordingly, the present invention provides a laundry treatment composition comprising:

1. a) an oxazoline material which is included in a polymer having at least two oxazoline-ring moieties; and,
2. b) at least one textile compatible carrier selected from the group consisting of detersive surfactants and rinse conditioners.

In a preferred embodiment the detersive surfactant is chosen from anionic and/or nonionic surfactants.

In another preferred embodiment the rinse conditioner is a quaternary ammonium compound.

In a preferred embodiment the polymer has a glass transition temperature of less than 30°C. Preferably the polymer is an oxazoline ring-functionalised poly(styrene-acrylic) polymer.

A further aspect of the present invention provides a method of treating fabric comprising:

1. a) provision of a composition comprising an oxazoline material which is included in a polymer having at least two oxazoline-ring moieties, and a textile compatible carrier selected from the group consisting of detersive surfactants and rinse conditioners, which composition is dissolved or dispersed in an aqueous medium;
2. b) contacting fabric which comprises fibres of oxidised cellulose with the aqueous medium of a); and,
3. c) drying the treated fabric.

A yet further aspect of the invention relates to the use of an oxazoline material which is included in a polymer having at least two oxazoline-ring moieties in the treatment of fabric which comprises oxidised cellulose to provide a colour care benefit to the fabric.

All percentages used herein refer to weight percentages by weight of laundry treatment composition unless otherwise stated.

Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about".

The laundry treatment composition may take many varied forms, for example a main wash detergent composition, or a rinse conditioner. The composition may alternatively be in the form of a spray or a foaming product, for application before or after the laundry process. Preferably the laundry treatment composition is a main wash composition or a rinse conditioner composition.

The oxazoline material is included in a polymer having at least two oxazoline-ring moieties.

The oxazoline material may be copolymerised as part of a polymer chain. For example a long chain polymer comprising side chains which in turn comprise oxazoline rings. Therefore the oxazoline material still bears at least two oxazoline-ring moieties, and preferably more. Examples of these materials are oxazoline ring-functionalised poly(styrene-acrylic) polymers, available from Nippon Shokubai as EPOCROS(Trademark).

For the avoidance of doubt, oxazoline polymers which do not contain any oxazoline ring moieties are outside the scope of this invention.

Preferably, the material is a polymer having at least two oxazoline groups with a glass transition temperature of below 30°C, examples being Epocros^™ K-2020E and Epocros^™ K-2010E.

The compositions of the invention, when applied to fabric, can be cured at ambient temperature (full curing taking between 1 and 14 days) or at elevated temperature, for example a tumble dryer (curing taking between 30 minutes and 4 hours) or by ironing (curing taking between 1 and 10 minutes) or a combination of these methods.

The level of oxazoline material present in the laundry treatment composition is from 0.1 to 30 wt.%. The inclusion levels are based on actual oxazoline comprising material actives, as the material can be provided as an emulsion, or dispersion of solids in a liquid. The laundry compositions may be in concentrated form, whereby the aforementioned inclusion levels are appropriate, or it may take a dilute form, whereby preferred inclusion levels of the oxazoline material are 0.01 to 10 wt.%.

The oxazoline ring moiety is believed to function as a reactive agent for oxidised cellulose, by ring-opening reaction of the oxazoline ring with a carboxylic acid (or carboxylate) present in oxidised cellulose. The reaction forms an amide ester link between the oxidised cellulose and the oxazoline material.

This reaction reduces the amount of oxidised cellulose present in the fabric, so reducing the amount of associated oxidative damage to the fabric and thus reducing the colour negative. By reacting at the carboxylic acid group, the site of the damage is effectively masked from further chemical processes. The reaction also removes any propensity for the site to bind transition metals such as iron(III), thus reducing yellowing.

The oxazoline material has two or more oxazoline moieties and can be used to crosslink oxidised cellulose.

The fabric treated may be any cellulose-fibre containing fabric. These encompass cotton, cotton-rich fabrics and polyester-cotton fabric mixes. Preferably the fabric comprises at least 50% cellulosic fibres.

The method of treating fabric comprises the following steps:

1. a) provision of a composition comprising an oxazoline material which is included in a polymer having at least two oxazoline-ring moieties, and a textile compatible carrier selected from the group consisting of detersive surfactants and rinse conditioners, which composition is dissolved or dispersed in an aqueous medium;
2. b) contacting fabric which comprises fibres of oxidised cellulose with the aqueous medium of a); and,
3. c) drying the treated fabric.

The drying step of the method starts the curing process of the polymer.

The fabrics can be cured at ambient temperature (full curing taking between 1 and 14 days) or at elevated temperature, for example a tumble dryer (curing taking between 30 minutes and 4 hours) or by ironing (curing taking between 1 and 10 minutes) or a combination of these methods.

The curing process occurs such that the oxazoline groups react with the carboxylate groups present on the oxidatively-damaged cellulose of the fabric.

Preferably the aqueous medium provided in part a) of the method is a main wash or rinse liquor from a laundering process.

Laundering process used herein refers solely to the wash and rinse process. This process may be done by machine (automatic, semi-automatic or manual), or by hand.

The compositions of the invention may be used outside this defined laundry process (either by a pre- or post treatment in reference to the main wash and rinse), but preferably the composition is applied as part of the laundry process as defined.

The use of an oxazoline material which is included in a polymer having at least two oxazoline-ring moieties in the treatment of fabric which comprises oxidised cellulose to provide a colour care benefit to the fabric can be achieved in various ways.

The oxazoline material which is included in a polymer having at least two oxazoline-ring moieties can be part of a cellulosic textile substantive material, which binds to one surface of the cellulosic textile, and allows reaction with oxidised cellulose to take place via an oxazoline ring moiety. Having at least two oxazoline rings to enable cellulosic crosslinking to occur via each oxazoline ring.

The colour care benefit provided to the fabric can be the reduction in colour fading of the fabric, or dye transfer inhibition. Preferably the colour care benefit is the reduction in colour fading of the fabric.

In the context of the present invention the term "textile compatible carrier" includes a component which can assist in the interaction of the cellulose cross-liking agent with a textile. The carrier is selected from a detersive surfactant or a rinse conditioner compound.

If the textile compatible carrier is a detersive surfactant, then preferably it is selected from anionic, nonionic, cationic, zwitterionic or amphoteric detersive surfactants.

More preferably the detersive surfactant is an anionic and/or nonionic surfactant.

The composition comprises between 2 to 70 wt% of a detersive surfactant, most preferably 10 to 30 wt %. The detersive surfactant may be chosen from the surfactants described "Surface Active Agents" Vol. 1, by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, in the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981. Preferably the surfactants used are saturated.

Suitable nonionic detergent compounds which may be used include, in particular, the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are C₆ to C₂₂ alkyl phenol-ethylene oxide condensates, generally 5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and the condensation products of aliphatic C₈ to C₁₈ primary or secondary linear or branched alcohols with ethylene oxide, generally 5 to 40 EO.

Suitable anionic detergent compounds which may be used are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radicals.

Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher C₈ to C₁₈ alcohols, produced for example from tallow or coconut oil, sodium and potassium alkyl C₉ to C₂₀ benzene sulphonates, particularly sodium linear secondary alkyl C₁₀ to C₁₅ benzene sulphonates; and sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum. The preferred anionic detergent compounds are sodium C₁₁ to C₁₅ alkyl benzene sulphonates and sodium C₁₂ to C₁₈ alkyl sulphates. Also applicable are surfactants such as those described in EP-A-328 177 (Unilever), which show resistance to salting-out, the alkyl polyglycoside surfactants described in EP-A-070 074, and alkyl monoglycosides.

Suitable amphoteric surfactants are amine oxides or betaines.

Preferred surfactant systems are mixtures of anionic with nonionic detergent active materials, in particular the groups and examples of anionic and nonionic surfactants pointed out in EP-A-346 995 (Unilever). Especially preferred is surfactant system that is a mixture of an alkali metal salt of a C₁₆ to C₁₈ primary alcohol sulphate together with a C₁₂ to C₁₅ primary alcohol 3 to 7 EO ethoxylate.

The nonionic detergent is preferably present in amounts greater than 10%, e.g. 25 to 90 wt % of the surfactant system. Anionic surfactants can be present, for example, in amounts in the range from about 5% to about 40 wt % of the surfactant system.

If the textile compatible carrier is a rinse conditioner compound, then preferably the textile compatible carrier is a cationic compound.

Preferred cationic compounds are quaternary ammonium compounds.

It is advantageous if the quaternary ammonium compound is a quaternary ammonium compound having at least one C₁₂ to C₂₂ alkyl chain.

It is preferred if the quaternary ammonium compound has the following formula: in which R¹ is a C₁₂ to C₂₂ alkyl or alkenyl chain; R², R³ and R⁴ are independently selected from C₁ to C₄ alkyl chains and X^- is a compatible anion. A preferred compound of this type is the quaternary ammonium compound cetyl trimethyl quaternary ammonium bromide.

A second class of materials for use with the present invention are the quaternary ammonium of the above structure in which R¹ and R² are independently selected from C₁₂ to C₂₂ alkyl or alkenyl chain; R³ and R⁴ are independently selected from C₁ to C₄ alkyl chains and X^- is a compatible anion.

Other suitable quaternary ammonium compounds are disclosed in EP 0 239 910 (Proctor and Gamble).

The cationic compound may be present from 1.5 wt % to 50 wt % of the total weight of the composition. Preferably the cationic compound may be present from 2 wt % to 25 wt %, a more preferred composition range is from 5 wt % to 20 wt %.

Compositions suitable for delivery during the rinse cycle may also be delivered to the textile 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 during a tumble dryer cycle.

The composition may comprise one or more builders. Such materials may suitably be aluminosilicates, silicates, carbonates, citrates, polycarboxylates, complexing agents, and phosphates.

Where builder is present, the compositions may suitably contain from 10 to 70 wt.% of detergency builder. Preferably the total level of builder is less than 20 wt.%.

Examples of suitable zeolites are: zeolite A, zeolite B (also known as zeolite P), zeolite C, zeolite X, zeolite Y and also the zeolite P-type as described in EP-A-0,384,070.

The composition may also comprise a complexing agent such as: ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, alkyl- or alkenylsuccinic acid, nitrilotriacetic acid, or, mixtures thereof.

Alternatively, or additionally to the aluminosilicate builders, phosphate builders may be used. In this art the term 'phosphate' embraces diphosphate, triphosphate, and phosphonate species. Other forms of builder include silicates, such as soluble silicates, metasilicates, layered silicates (e.g. SKS-6 from Hoechst).

For low cost formulations carbonate (including bicarbonate and sesquicarbonate) and/or citrate may be employed as builders.

The composition may comprise one or more polymers. Examples are: carboxymethylcellulose, poly(ethylene glycol), poly(vinyl alcohol), poly(vinylpyridine-N-oxide), polycarboxylates (such as polyacrylates, maleic/ acrylic acid copolymers and lauryl methacrylate/acrylic acid copolymers), and mixtures thereof. The composition may additionally comprise soil release polymers such as block copolymers of polyethylene oxide and terephthalate.

The composition may additionally comprise a dye transfer inhibition agent. These prevent migration of dyes, especially during long soak times. Such agents are preferably selected from polyvinylpyrridine N-oxide (PVNO), polyvinyl pyrrolidone (PVP), polyvinyl imidazole, N-vinylpyrrolidone and N-vinylimidazole copolymers (PVPVI), and copolymers thereof, and/or mixtures thereof.

The amount of dye transfer inhibition agent if present, in the composition will be from 0.01 to 10 %, preferably from 0.02 to 5 %, more preferably from 0.03 to 2 %, by weight of the composition.

Additional colour benefits can be obtained by the incorporation of enzymes. Enzymes contemplated for use in laundry detergent compositions include proteases, alpha-amylases, cellulases, lipases, peroxidases/oxidases, pectate lyases, mannanases, or mixtures thereof.

The compositions of the invention may also contain optional colour care benefit agents. Preferred colour care benefit agents are polysaccharides. Typically, the wash/rinse liquor will comprise around 0.01 g/L of a polysaccharide colour care benefit agent.

Preferably the polysaccharide is a beta 1-4 polysaccharide; more preferably a cellulose derivative, such as a hydroxy C2-C4 alkyl derivative. More preferably the hydroxy C2-C4 alkyl derivative is a hydroxy ethyl derivative.

Preferably the degree of substitution (DS) of the polysaccharide is 1.5-2.25. Preferably the molecular weight of the polysaccharide is 100,000 to 500,000 Dalton.

The composition may also contain other conventional detergent ingredients such as e.g. fabric conditioners including clays or silicones, foam boosters, anti-corrosion agents, soil-suspending agents, anti-soil redeposition agents, dyes, anti-abrasion agents, anti-microbials, stabilisers, tarnish inhibitors, or perfumes.

Further optional ingredients include non-aqueous solvents, perfume carriers, fluorescers, colourants, hydrotropes, antifoaming agents and opacifiers.

In addition, compositions may comprise one or more of anti-shrinking agents, anti-wrinkle agents, anti-spotting agents, germicides, fungicides, anti-oxidants, UV absorbers (sunscreens), heavy metal sequestrants, chlorine scavengers, dye fixatives, anti-abrasion agents, anti-corrosion agents, drape imparting agents, antistatic agents and ironing aids. The lists of optional components are not intended to be exhaustive.

In order that the invention may be further understood and carried forth into practice it will be described below with reference to non-limiting examples.

Indanthrene, Remazol and Procion refer to the various dyes used in the examples:-

• Indanthrene Blue RS (Vat Blue 4)
• Remazol Brilliant Orange 3R (Reactive Orange 16)
• Procion Yellow H-EXL (Reactive Yellow 138:1)
• Procion Crimson H-EXL (Reactive Red 231)
• Procion Navy H-EXL
• Remazol Brilliant Yellow RNL (Reactive Orange 107)
• Remazol Red RB (Reactive Red 198)
• Remazol Blue BB (Reactive Blue 220)
• Remazol Brilliant Yellow RNL (Reactive Orange 107)
• Remazol Red RB (Reactive Red 198)
• Remazol Black B (Reactive Black 5)

A load comprising 4 panels of each of the following were washed 10 times in a front loading washing machine (Whirlpool Electronic AWM6100-6K, 40°C cotton cycle) using Prenton water and 100g Persil Performance to generate damage on the cloth. The fabrics were tumble dried (Miele Novotronic T430) after every wash. 1. BP1-K 2% Indanthrene Blue RS 2. BP2-K 4% Remazol Brilliant Orange 3R 3. BP3-K 3.85% Procion Yellow H-EXL 1.35% Procion Crimson H-EXL 2.41% Procion Navy H-EXL 4. BP4-K 1.6% Remazol Brilliant Yellow RNL 1.2% Remazol Red RB 1.2% Remazol Blue BB 5. BP5-K 2.2% Remazol Brilliant Yellow RNL 1.3% Remazol Red RB 1.3% Remazol Black B 1. BP3-W 3.85% Procion Yellow H-EXL 1.35% Procion Crimson H-EXL 2.41% Procion Navy H-EXL 2. BP4-W 1.6% Remazol Brilliant Yellow RNL 1.2% Remazol Red RB 1.2% Remazol Blue BB 3. BP5-W 2.2% Remazol Brilliant Yellow RNL 1.3% Remazol Red RB 1.3% Remazol Black B

The fabrics were cut into 100 x 50cm pieces, folded into 50 x 50cm double panels and overlocked around the three remaining edges. Four pieces of each cloth were used (total 32 pieces, weight 2.1kg).

After the washes were complete, four new loads were prepared containing:

• 1 piece of each of the washed fabrics detailed above,
• 1 new piece of each of the fabrics detailed above, and,
• 900g of non-fluorescent woven cotton sheeting.

Total load weight was 2.0kg. Standard colour measurements (CIELAB coordinates, reflectance and K/S spectra, UV excluded, 400nm cut-off) were taken of all the coloured fabrics using a Datacolor Spectraflash SF600+ spectrometer.

The loads were then washed in the same Whirlpool machine using the same wash program using the following products:

The fabrics were tumble dried (Miele Novotronic T430) after each wash cycle. The fabrics were measured after the 9^tn wash using the Spectraflash spectrometer using the same conditions as before.

The parameter ΔΔL* (Delta Delta L*) is measured on a reflectance spectrophotometer. After calibrating the machine using the standard black trap and white tile, the colour coordinates of the white tile are measured and used as the reference standard. The coloured fabrics used in the test are then measured against this standard. The measurements are known as the CIELAB space coordinate system based around the theory of the three opponent pairs of colour vision:

• L* = lightness (0 = black, 100 = white)
• a* = red-green (-a = green, +a = red)
• b* = blue-yellow (-b = blue, +b = yellow)

For each fabric, an average of these values is then calculated. After washing, the measurements are repeated. The changes in these values can thus be calculated. Given that the dyes used are stable and no bleach is present in the system, the largest change occurs in the lightness parameter - the actual shade of the fabric remains relatively constant but the fabric becomes lighter.

Analysis of the data showed that the major changes were in the lightness (L*), as the reactive dyes used are known for their light/oxidative stability and thus no major changes in shade (which would be evident in the a and b colour coordinates). Thus, a small ΔΔL* shows that the fabric has become only slightly lighter while a negative ΔΔL shows that the fabric has actually become darker.

9 wash Delta Delta L* (ΔΔL*) measurements (95% confidence limits in brackets):-

• K = Knitted fabric, W = Woven fabric,
• washed = fabric already washed 10 times, new = new fabric

In all cases, the combination of Comfort and K2010E shows the largest benefit.

In four cases the combination has actually made the fabric slightly darker (producing a negative ΔΔL* value).

The polymer can be incorporated into main wash powders or liquids (most preferably those based around cationic surfactants) or rinse conditioner products.