Such compositions comprise various aromatic compounds, commonly known as developers (also known as precursors or primary intermediates), together with various other compounds, commonly known as couplers. These are referred to as oxidative hair colouring agents because they require an oxidising agent for formation of colour.

In our earlier publications W098/52519, W098/52520, W098/52521, W098/52522 and W098/52523 we describe specific hair colouring compositions which use defined types of oxidative hair colouring agents. In particular, in these publications it is essential that the couplers are selected from three groups (A), (B) and (C), which give cyan, yellow and magenta colours respectively when coupled with a developer. The"magenta"couplers (C) are pyrazolone derivatives having an active leaving group Z.

These publications include various specific examples of pyrazolones. These include 1-phenyl, 3-methyl pyrazolone ; 3- methyl pyrazolone; 1-phenyl pyrazolone; and 1,3-dimethyl pyrazolone.

It is essential that the composition comprises at least one developer selected from amino aromatic systems capable of being oxidised and thereafter undergoing only a single electrophilic attack (single electrophilic attack developers). According to these publications the combination of the chosen couplers and this specific type of developer has the advantage that the reaction chemistry is closely defined, because each developer molecule reacts only once with a single coupler molecule. Thus it is possible to predict with precision the compounds which will

be present in the hair at the end of the colour forming reaction.

GB 1,025,916 also describes combinations of developers and couplers of this general type, but itself has disadvantages overcome by the international publications discussed above.

We have found that although these compositions have significant advantages, there is room for improvement. In particular, we find that the colours produced, although vibrant and easily predictable tend to give higher fade under the influence of ultraviolet light (UV fade) than would be desirable. Thus when the consumer\'s hair has been coloured, over a period of weeks there is a noticeable fading in the colour, if exposed to substantial amounts of UV.

It would be desirable to improve the UV fade resistance properties of compositions which contain the pyrazolone couplers.

Various other publications have disclosed the use of pyrazolones in hair colouring compositions. For instance FR 1426889 discloses 1-phenyl, 3-methyl pyrazolone in an example. EP-A-951,900 discloses various 1-phenyl pyrazolones. US 3, 884, 627 mentions 1,3-dimethyl pyrazolone in a long list of hair colouring components and does not exemplify its use.

Corbett in J. Dyes and Pigments 1998 reviews oxidation hair dye literature and mentions in passing that N-phenyl, 3-ethyl pyrazolone may be used in combination with para- phenylene diamine (PPD).

None of these references is concerned with the problems which arise with the combination, essential in the international publications discussed above, of a defined pyrazolone coupler with a single electrophilic attack developer, namely reduced W fade resistance.

According to the invention we provide a hair colouring composition comprising one or more developers selected from amino aromatic systems capable of being oxidised and thereafter undergoing at least two electrophilic attack reactions, and one or more couplers selected from of the formula I: in which X is a non-leaving substituent, and Z is an active leaving group, and Y is an active leaving group or a non-leaving substituent, such that in the presence of an oxidising agent the or each developer reacts with the or each coupler substantially only at the position having the active leaving group Z and, if Y is an active leaving group, Y, provided that if X is phenyl then Y is not ethyl or methyl.

The invention also provides a hair colouring kit comprising the defined developer and the defined coupler separately packaged.

The invention also provides a method for colouring hair comprising applying to the hair the defined developer and the defined coupler.

We find surprisingly that the choice of developers which are not the single electrophilic attack developers essential in the earlier international publications and GB 1,025,916 significantly improves the W fade resistance of the resulting colour.

Consequently, the invention also provides the use of the defined developers to improve the W fade resistance of compositions comprising the defined developers.

It is unclear precisely why this benefit arises, but nevertheless it is a demonstrable benefit, as will be seen below.

In the invention the developer is an amino aromatic compound which has a structure such that it is capable of being oxidised by an oxidising agent. The structure is also such that the oxidised developer is capable of undergoing electrophilic attack on at least two other molecules. Suitable developers of this type include aminoaromatic systems in which there are two primary amine groups.

The defined type of coupler is such that in the presence of an oxidising agent the majority couple with the developer at only one position. Certain couplers, having an additional active leaving group Y, also react at the Y position.

The coupler is of the same general type as disclosed in W098/52519, W098/52520, W098/52521, W098/52522 and W098/52523 as magenta couplers. However, we now find that certain magenta couplers not specifically disclosed in those publications have particular advantages. These preferred materials are discussed in more detail below. The couplers produce a magenta colour on reacting with a developer molecule. The defined coupler may be the only coupler in the composition but preferably other types of coupler are also used to give a range of different colours.

The coupler is of a specific formula which has an active leaving group Z (and optionally Y) at a defined site.

By an"active leaving group we mean any group which can be removed (under the conditions prevailing during the hair- dyeing process) so that the developer reacts at that position in the coupler molecule. A bond between the coupler and developer molecule is thus formed at the site of the active leaving group. Examples of active leaving groups are H, PhO, Cl, Br, alkoxy (RO) such as phenoxy PhO, and RS- in which R is alkyl or aryl, but any leaving group which

leaves during the reaction so as to allow coupling between developer and coupler is suitable.

If Y is an active leaving group it may be any of those listed above for Z.

Generally Y is a non-leaving substituent. Preferably also Z is H.

X can be H, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, alkaryl, aralkyl,-R\'NHCOR,-R\'CONHR,-R\'OH,-R\'S02R, -R\'SO2NHR or-R\'OR. R is H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkaryl or aralkyl, and R\'is alkylene, cycloalkylene, alkenylene, cycloalkenylene, arylene, alkarylene or aralkylene (or substituted versions of any of these). Suitable substituting groups include OH,-OR, Cl, Br, F,-CO2H,-CO2R,-NH2, and-COR.

X is preferably selected from methyl and phenyl.

Y may be Ht-OH,-CO2H,-CO2R, F, Cl, Br,-CN,-N02, CF3, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkaryl, aralkyl,-NH2,-NHR,-NR2,-NHCOR,-R\'NHCOR,- CONHR,-R\'CONHR,-R\'OH,-SO2R,-S02NHR,-R\'S02R,-R\'S02NHR,- SO3H,-OR,-R\'OR or-COR. R is H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkaryl or aralkyl, and R\'is alkylene, cycloalkylene, alkenylene, cycloalkenylene, arylene, alkarylene or aralkylene (or substituted versions of any of these). Suitable substituting groups include OH, -OR, Cl, Br, F,-CO2H,-C02R,-NH2, and-COR.

Preferably Y is selected from phenyl and NHCOR in which R is alkyl and is preferably selected from phenyl and N- acetyl.

In preferred coupler compounds X is methyl and Y is phenyl; X is phenyl and Y is NHCOR, preferably N-acetyl; X is methyl and Y is NHCOR, preferably N-acetyl; X is methyl or phenyl and Y is NHCOPhNH2 ; X is phenyl and Y is phenyl.

In the invention when X is phenyl then Y is not ethyl or methyl. Preferably when X is phenyl then Y is not

hydrogen. Preferably also when X is phenyl then Y is not amino.

Preferred compounds of the formula I are novel for use in hair colouring compositions. Thus according to a further aspect of the invention we provide a hair colouring composition comprising one or more developers and one or more couplers selected from 1-methyl, 3-N-acetyl pyrazolone; 1-methyl, 3-phenyl pyrazolone; 1-phenyl, 3-N-acetyl pyrazolone; and 1-methyl, 3-phenyl pyrazolone.

The defined couplers can be used in amounts of from for instance 0.01 to 4%, preferably 0.01 to 2%, more preferably 0.03 to 3, eg 0.03 to 2%, and in some compositions not more than 1 or 0.5%.

The developer is an amino aromatic system capable of being oxidised and thereafter undergoing at least two electrophilic attack reactions. It can for instance be selected from ortho or para-disubstituted benzene compounds, disubstituted pyridine compounds, disubstituted pyrimidines and diaminosubstituted pyrazoles. Preferably it is para- phenylene diamine.

Preferably the composition contains no developers which are amino aromatic systems capable of being oxidised and thereafter undergoing only one electrophilic attack reaction (single electrophilic attack developers).

Developer is often included in the composition in amounts of from 0.01 to 7%, preferably 0.01 to 5% by weight based on total composition applied to the hair. Preferred amounts of developer are from 0.3 to 4%, eg 0.3 to 2%, preferably 0.4 to 3%, eg 0.4 to 1. 5%.

For both developers and couplers the solubility properties can be important. The developer and coupler compounds themselves should have solubility such that they can be formulated in appropriate concentrations. They preferably have solubility of at least 5 g/100 ml deionised water at pH about 10 and 25°C.

The compositions of the invention may contain any other suitable oxidative dye materials, for instance other couplers of the general types disclosed in W098/52522 and the other PCT publications in this series referred to above, and other oxidative dye compounds.

An optional component of the composition is an antioxidant. It may be selected from for instance sulphites such as sodium sulphite, hydroquinone, sodium bisulphite, sodium metabisulphite, thioglycolic acid, sodium dithionite, erythrobic acid and other mercaptans, ascorbic acid and n- propyl gallate.

If used, antioxidant is included in an amount of at least 0.01 and usually not more than 3 or 4 wt. %, based on total weight of composition applied to the hair.

For the developers and couplers to be effective in forming colour they require the presence of an oxidising agent. This oxidising agent is normally included in the composition just before it is applied to the hair. Normally the composition of the invention will be supplied in at least two individual packages such as bottles, the oxidising agent being included in one package and the developers and couplers being included in another.

A preferred oxidising agent is hydrogen peroxide.

This is often used in amounts up to 10 wt. %, based on composition applied to the hair. Other oxidising agents which may be used include other inorganic peroxygen oxidising agents, preformed organic peroxyacid oxidising agents and other organic peroxides such as urea peroxide, melamine peroxide, and mixtures of any of these.

Suitable oxidising agents are preferably water-soluble, that is they have a solubility of at least about 5g in 1,000 ml of deionised water at 25°C ("Chemistry"C. E. Mortimer, 5th Edition, page 277).

Usually the colouring compositions of the invention have pH above 7, in particular above pH 8 or 9. A pH of from 9 to 12 is often suitable. The systems of the

invention can also be incorporated into low pH (eg pH 1 to 6) hair colouring systems.

In practice the composition of the first aspect of the invention may be supplied to the consumer as a single package containing developer and coupler in a single unit such as a bottle.

It is also possible to supply the composition so that the developers are individually packaged and the couplers are individually packaged. Couplers may be supplied as a preformed mixture selected to give a particular colour.

Alternatively they can be supplied separately for mixing by the consumer to give a variety of different hair colours.

In all cases, the essential components are mixed to form the composition of the invention before application to the hair.

Generally oxidising agent is individually packaged separately from any of the colouring components. It is often mixed with these to form a component of the hair colouring composition before application to the hair.

Alternatively it can be applied to the hair separately either before or after the hair colouring composition.

The developers, couplers and oxidising agent, and any other materials to be applied to the hair as components of the composition of the invention, may be provided in any suitable physical form. A preferred physical form is liquid. The liquid may be of low viscosity, for instance it may be water thin, or it may be of higher viscosity. The material may be suspended in a gel network. The gel may be solid or of low viscosity.

The materials for colouring the hair are often formulated so that when they are mixed to form the composition of the invention for application to the hair they form a product of cream-like consistency, which is convenient for application to the hair. The final composition which is applied to the hair is often in the form of an emulsion.

Each individual material may be supplied in a form such that the composition containing it has a pH of above or below 7. For instance it may be from pH 1 to 11. In order to assist solubility of the various components, particularly developers and couplers, in a water-based carrier, the carrier may have a pH of above 6.1 or 6.5 or even above 7, for instance from pH 8 or 9 to pH 10 or 11. A pH as supplied of from 1 to 6 can assist in improving stability of the components.

The materials may be provided such that the pH of the final composition when mixed for application to the hair has a pH below 7 even though one of the components used to form it has a pH of above 7. Alcohols such as ethanol in amounts of from for instance 5 to 10 or 25% may be included to aid solubility of the developers and, particularly, the couplers in a water-based carrier.

The compositions may contain other optional ingredients. These can include other oxidative and non- oxidative colouring agents, buffering agents, hair swelling agents, catalysts for the oxidising agent, thickeners, diluents, enzymes, surfactants (especially anionic amphoteric, non-ionic or zwitterionic surfactants), proteins and polypeptides and derivatives thereof; water-soluble or solubilizable preservatives; dye removers; H202 stabilisers; moisturising agents; solvents; anti-bacterial agents; low temperature phase modifiers; viscosity control agents; hair conditioning agents; enzyme stabilisers; Ti02 and TiO2- coated mica; perfumes and perfume solubilizers; chelating agents. Other optional materials include anti-dandruff actives such as ZPT. Details of suitable optional ingredients can be found in W098/52522.

Examples In the following examples various standard tests are used as follows.

I Assessment of Initial Colour and Colour Change (Measurement of hE)

The equipment used to measure both the initial colour and colour change of substrates (hair/skin) dyed with colouring compositions of the present invention is a Hunter Colourquest spectrophotometer. The value used to express the degree of colour change on any particular substrate is Delta E (AE). Delta E, as defined herein, is represented by a factual sum of L, a, and b values such that: AE = (AL\'+ Aa\'+ Ab\') % and L is measure of lightness and darkness (colour intensity), wherein L = 100 is equivalent to white, and L = 0 is equivalent to black. Further,"a"is a measure of the red and green quotients (colour hues) such that positive equates to red and negative to green and"b"is a measure of the yellow and blue quotients (colour hues) such that positive equates to yellow and negative equates to blue.

Hunter Colourquest measurements can be carried out on the Hunter Labscan Colourimeter which is a full scanning spectrocolorimeter with a wavelength of from 400-700 nanometers which records the colour of test hair switches (tresses) in terms of"L","a"and"b"values. The machine is set to: mode-0/45; port size-1 inch; view size-1 inch; light-D65; field of view-10° ; UV lamp/filter- none. The hair is placed in a sample holder designed to hold the hair in uniform orientation during measurement.

Equivalent colorimeters can be used, but it must be ensured that the hair does not move during measurement. The hair must be spread to cover the 1 inch port during colour measurement. Dots are placed on the switch holder to guide the positioning of the holder at the port. The dots are lined up with a mark on the port and readings are taken at each spot.

Eight measurements are run per switch, 4 on each side, and three switches are run per treatment.

II Standard Hair Switch

The compositions according to the present invention can be used to colour hair of all colours, types and condition.

For the purposes of illustration various test hair switches can be tested herein. Two of these standard hair switches can be measured in terms of their approximate L, a, b values.

L a b Light brown (permed and bleached) about 60 about 9 about 32 40% grey dark brown 35-37 4.5-5.5 11.5-12.7 Yak hair (virgin or permed and/or bleached) can also be used. It has values of: L = about 82 to 83, a = about-0.5 to 0.7, b = about 11 to 12.

III Hair Switch Colouring Method To colour hair, a 4 gramme switch of about 8 inch long hair (or a 2 gramme switch of 4 inch long hair) is hung over a suitable container. The test colouring product is then prepared (ie, where applicable the separate bottle components are mixed together) and about 2 grammes of product per gramme hair is applied directly to the test hair switch. The colourant is massaged through the hair switch for up to about 1 minute and then left on the hair switch for up to about 30 minutes. After rinsing with running water for about 1 or 2 minutes the coloured hair switch is then cleansed (according to the shampoo protocol IV below) and dried. Drying can be effected either naturally (without heat assistance) or using a drier. The colour development (initial colour) of the coloured, cleansed, dried test hair switch can then be assessed using the Hunter Colourquest spectrophotometer.

IV Hair Switch Cleansing Method A 4 gramme, 8 inch test switch (or a 2 gramme, 4 inch test switch) of coloured hair is clamped over a suitable container and rinsed thoroughly for about 10 seconds using

warm water (at about 100°F at about 1.5 gallons/minute pressure). Shampoo (about 0.1 ml non-conditioning shampoo per gramme hair) can then be applied directly to the wet test switch using a syringe. After lathering the hair for about 30 seconds the hair is rinsed in running water for about 30 seconds. The shampoo and lathering process is then repeated with a final 60 second rinse. Excess water can be removed (squeezed) from the test switch using the fingers.

The test switch is then dried either naturally, or using a pre-heated dryer box at about 140°F (for about 30 minutes).

Example 1 Hair switches were dyed with the coupler and developer system specified below, washed and dried. Samples were then subjected to 21 hours in a Xenotester. E = 44 W/m2 (equivalent to 7 days European sunlight) @ 300-400 nm, 65% Relative humidity, 40-50°C, turning mode. Lab measurements were recorded before and after exposure for a delta E fade to be calculated.

Results are shown below in Table 1.

Table 1 Combination L a b delta E change Before virgin: PPD + 16. 39 5. 19-0.11 1,3-dimethylpyrazolin- 5-one After virgin: PPD + 19. 90 5. 47 1. 99 4. 10 1,3-dimethyl pyrazolin- 5-one Before virgin: 25.19 23.53-0.25 Dichloroparaamino phenol + 1,3- dimethylpyrazolin-5- one After virgin: 30.48 23. 16 2.43 5. 94 Dichloroparaamino phenol + 1,3- dimethylpyrazolin- 5-one

These results clearly show the W fade benefits given by PPD (paraphenylene diamine) in comparison with dichloroparaaminophenol together with a preferred pyrazolone coupler.