The present invention relates to bleaching compositions comprising radical initiators. More particularly the invention relates to laundry treatment compositions for the spot or other direct treatment of soiled articles and to a process using the said compositions.

Typical laundry stains contain chromophores based on carotenoids, phenolics and phytoestrogens. Radical photoinitiators are known as stain bleaches for laundry application. These are materials, which on exposure to light generate reactive radicals. In turn, these radicals cause chemical changes in the stain, which decolourise it.

Radical photo-initiators are well known in the unrelated fields of polymerisation and curing reactions.

Other types of radical initiators are known (such as thermal or chemical initiators) and use of these in bleaching and sewage or other effluent treatment has also been envisaged.

It is a well established problem in the field of laundry bleaching that compounds which can bleach stains will also have the capacity to bleach dyes present in the cloth.

Consequently, much effort has been spent in finding bleaches, which are effective against stains but are ineffective against dyes. This problem is especially difficult to solve in the context of porous fibres such as dyed cotton and other dyed cellulosics, particularly where these have been dyed with common dyestuffs based on strongly coloured azo-, anthroquinone or phthalocyanine compounds.

UK Patent application no: 9917451.8, teaches that photoinitiators with high logarithm of octanol-water partition coefficient (logP) give good stain bleaching with little dye damage on the fabric. This is highly desirous as consumers wish to remove stains without damaging their coloured fabric. The most preferred photoinitiators are those with logP values in excess of 4.0.

Many effective photoinitiators have logP values much lower than 4.0 and are known to give some fabric dye damage particularly when used at high levels.

For example 1-hydroxy-cyclohexyl-phenyl-ketone has logP = 2.81, 2-hydroxy-4'-hydroxyethoxy-2-methyl-propiophenone has logP = 0.84.

It would be advantageous if low logP initiators could be used without causing damage.

A prior approach to this problem is disclosed in co-pending UK patent application UK 9929693.1. This teaches the use of radical terminators in conjunction with radical initiators to reduce dye damage. These systems are effective under both wet and dry conditions. However the use of two active ingredients may not always be desirable, particularly for reasons of cost.

We have found that application of initiators from surfactants in a liquid-crystalline phase reduces dye damage without a corresponding reduction of stain bleaching.

The swelling behaviour of cotton is discussed in 'Cellulose - Structure Accessibility and Reactivity', Gordon and Breach Science Publishers and references therein. Commonplace solvents such as water and ethanol are effective at swelling the amorphous regions of cotton and other cellulosics. It is believed that swelling is avoided by use of neat surfactant.

Accordingly, the present invention provides a fabric treatment composition which comprises:

• a) a radical initiator, and
• b) surfactant in a liquid-crystalline phase

Typical surfactant phases in the present specification comprise more than about 10% water.

In the context of this invention the term 'liquid crystalline phase' is meant to include both lamellar phase and other forms of liquid crystalline phases including hexagonal and cubic phases. The common property of these phases is that while a significant quantity of water may be present the water is structured by the presence of surfactant and its activity is greatly reduced. Liquid crystalline phases are well understood in the detergent art and most surfactants can be induced to for liquid crystalline phases over some region of their water/surfactant phase diagram.

The lamellar phase is a particularly preferred liquid crystalline phase.

It is believed that such formulations prevent the passage of the initiator into the regions of the fibres where the dye resides while allowing the initiator to come into contact with the stain, which is essentially superficial.

The present invention further provides a method for the treatment of fabrics, which comprises applying to the fabric a composition according to the invention.

The preferred radical initiators are photo and thermal initiators. The use of photo initiator systems is preferred as sunlight and other suitable sources of illumination are generally freely available. It is commonplace, for example, to dry laundered articles in sunlight.

The surfactant may be contained in a wipe ar swab and the wipe used to physically remove stain and apply photo-initiator to it. Alternatively, the composition may be applied directly to' the substrate being treated.

Surfactants may be employed in solid or liquid form..In some markets, liquid surfactants are preferred for ease of application. In other markets soft-solid forms will be preferred. Preferably, these can take the form of soap or other non-soap detergent bars, although embodiments of the invention may take the form of other applicator sticks.

A range of suitable application forms can be found in the art of deodorant sticks and other applicators.

The initiator may be a perfume material or the carrier of a perfume material. Inclusion of the initiator in a final composition together with the perfume is advantageous as both classes of materials may require careful dosing and the composition is generally not subjected to heating once the perfume has been added.

The photo-initiator system must generally be stored in the absence of light of wavelength below 500nm, to avoid photoreaction. An opaque packaging is sufficient for this purpose.

The surfactant may be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric and zwitterionic detergent active compounds, and mixtures thereof. It is necessary that the combination of surfactant and water present forms a liquid crystal phase. The size of the phase region over which such a phase forms can be modified by the presence of salts.

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.

Preferred soaps are those having a C8-C18 alkyl chain.

Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C₈-C₂₀ aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the C₁₀-C₁₅ 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).

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-C₁₅; primary and secondary alkylsulphates, particularly C₈-C₁₅ primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.

Cationic surfactants that may be used include quaternary ammonium salts of the general formula R₁R₂R₃R₄N⁺ 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 R₁ is a C₈-C₂₂ alkyl group, preferably a C₈-C₁₀ or C₁₂-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.

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

The photo-initiators can be hydrogen abstraction radical photoinitiators. These include benzophenones, acetophenones, pyrazines, quinones and benzils.

Bond cleavage photoinitiators are preferred. Suitable bond cleavage radical initiators may be selected from the following groups:

• (a) alpha amino ketones, particularly those containing a benzoyl moiety, otherwise called alpha-amino acetophenones, for example 2-methyl 1-[4-phenyl]-2-morpholinopropan-1-one (Irgacure 907, trade mark, ex CIBA), (2-benzyl-2-dimethyl amino-1-(4-morpholinophenyl)-butan-1-one (Irgacure 369, trade mark, ex CIBA);
• (b) alphahydroxy ketones, particularly alpha-hydroxy acetophenones, eg (1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one) (Irgacure 2959, trade mark, ex CIBA), 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, trade mark, ex CIBA); 2-hydroxy-2-methyl-1-phenylpropan-1-one (Esacure ™ KL200 ex Lamberti SPA); and, oligomeric polyfunctional alpha-hydroxyketones (such as Esacure KIP150 ex Lamberti SPA);
• (c) phosphorus-containing photoinitiators, including monoacyl and bisacyl phosphine oxide and sulphides, for example 2-4-6-(trimethylbenzoyl)diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide (Irgacure 819, trade mark ex CIBA), (2,4,6-trimethylbenzoyl)phenyl phosphinic acid ethyl ester (Lucirin TPO-L (trade mark) ex BASF);
• (d) dialkoxy acetophenones; particularly Benzildimethylketal (Esacure ™ KB1 ex Lamberti SPA);
• (e) alpha-haloacetophenones;
• (f) trisacyl phosphine oxides; and,
• (g) benzoin and benzoin-based photoinitiators.

Further suitable radical photoinitiators are disclosed in WO 96 07662 (trisacyl phosphine oxides), US 5399782 (phosphine sulphides), US 5410060, EP-A-57474, EP-A-73413 (phosphine oxides), EP-A-088050, EP-A-0117233, EP-A-0138754, EP-A-0446175 and US 4559371.

Other suitable radical photoinitiators are disclosed in EP-A-0003002 in the name of Ciba Geigy, EP-A-0446175 in the name of Ciba Geigy, GB 2259704 in the name of Ciba Geigy (alkyl bisacyl phosphine oxides), US 4792632 (bisacyl phosphine oxides), US 5554663 in the name of Ciba Geigy (alpha amino acetophenones), US 5767169 (alkoxy phenyl substituted bisacyl phosphine oxides) and US 4719297 (acylphosphine compounds).

Radical photoinitiators are discussed in general in A.F.. Cunningham, V. Desorby, K. Dietliker, R. Husler and D.G. Leppard, Chemia 48 (1994) 423-426 and H.F.Gruber, Prog. Polym. Sci., 17, (1992), 953-1044.

The preferred radical photoinitiators become active when excited by radiation falling generally in the range 290-800 nm. For example, natural sunlight, which comprises light in this region, will be suitable for causing the radical photoinitiator to undergo one of the reactions described above.

Preferably, the radical photoinitiator has a maximum extinction coefficient in the ultraviolet range (290-400 nm) which is greater than 100 mol^-1lcm^-1. Suitably, the radical photoinitiator is a solid or a liquid at room temperature.

Particularly preferred photo-initiators include alpha hydroxy ketones, particularly those containing a benzoyl moiety.

Suitably, the radical photoinitiator is substantially colourless and gives non-coloured photo products upon undergoing one of the reactions set out above.

Optionally, the compositions comprise sensitisers such as thioxanthones, for example as described in EP-A-0088050, EP-A-0138754, as well as one or more perfume components or a radical terminator.

The radical photoinitiators are preferably activated by ambient light eg, domestic lighting or sunlight. However, a separate light source (for example a tungsten filament or gas discharge tube) may be employed for activation of the photoinitiator.

In the alternative, the initiator may be a thermal initiator, which decomposes to form radicals on heating. As will be apparent, there will be some degree of overlap between the classes of initiator, which may be used in these two aspects of the invention. Some radical photoinitiators also decompose by heating (particularly at higher temperatures) and some thermal initiators decompose on exposure to light (particularly at shorter wavelengths).

Suitable thermal initiators include compounds comprising an azo group or a peroxygen group. Preferred materials exclude those containing a peroxygen group and include those forming a carbon-centred radical rather than an oxygen-centred radical.

The thermal initiators are preferably stable at ambient temperature. Temperatures to which.the thermal initiators should be heated to cause them to decompose are preferably in the range of up to 100°C, more preferably from 35°C to 90°C, most preferably 35°C to 40°C. Heat may conveniently be applied by means available in the laundering environment such as by use of an iron or tumble drier.

The invention will be further described with reference to the following non-limiting examples.

For all the examples, values given are the average of 4 experiments.

Cotton cloth samples were reactively dyed with Remazol Black B ™ so that the cloth contained 1.5x10^-4 mol kg^-1 of dye. This cloth is a sensitive monitor of dye damage.

Separate samples of white cloth were heavily stained with β-carotene (ex. Equest, Newcastle GB). These'cloths served as monitors of bleaching activity.

50g l^-1 of a C-12 soap in water (a waxy liquid-crystalline solid at room temperature) was melted by heating.

1% of Lucirin TPO-L or Irgacure 184 was dissolved in the hot liquid and then the solution poured into a plastic mould and allowed to solidify by cooling. The so-formed solid was wiped across the surface of β-carotene stained cotton and cotton dyed with Remazol Black B then irradiated in a Weatherometer™ for 6 minutes. Control experiments were also carried out using C-12 soap only.

After irradiation the stained cloth treated with initiator was clearly bleached and no dye damage on the dyed cloth above control could be observed. The control stained cloth showed no bleaching. ΔE of stained cloth compared to white original ΔE of black cloth compared to original Control (irradiation + rinse) 53.6 0.2 Soap only 52.7 0.4 Soap with 1% Irgacure 184 28.6 0.4 1% Irgacure 184 from ethanol - 3.5 Soap with 1% Lucirin TPO-L 17.5 0.4 1% Lucirin TPO-L from ethanol - 2.3

Table 1 Stain bleaching and Dye damage from Lucirin TPO-L applied from 50g/l C-12 soap.

Cotton cloth samples were reactively dyed with Remazol Black B ™ so that the cloth contained 1.5x10^-4 mol kg^-1 of dye. This cloth is a'sensitive monitor of dye damage.

Separate samples of white cloth were heavily stained with β-carotene (ex. Equest, Newcastle, G.B.). These cloths served as monitors of bleaching activity.

A C-14 soap was dissolved in hot water such that its concentration was 50gl^-1.

1% Irgacure™ 184 (ex. Ciba Speciality Chemicals, also sold under the Esacure™ KS 300 name by Lamberti Spa) was dissolved in the hot liquid and the solution then poured into a plastic mould and allowed to solidify by cooling. The so-formed solid was wiped across the surface of the β-carotene stained cotton and then irradiated in a Weatherometer™ for 6 minutes. The procedure was repeated for' the dyed cotton except the clothes were irradiated for 18 minutes. Control experiments were performed using C-14 soap only.

All clothes were then washed in water, dried and the CIELAB ΔE values of the stained clothes relative' to a clean white original measured using a reflectance spectrometer. The CIELAB ΔE values of the dyed cotton clothes were also measured relative to an untreated piece.

The experiment was repeated using 25, 75, 100 and 150 gl^-1 soap and the results shown in table 2. For comparison 1% of Irgacure 184 was applied from an ethanol solution, the ethanol dried and the cloth then irradiated wet with water or dry.

The results show that use of the soap solution reduces the damage to the coloured cloth whilst bleaching the stained cloth. ΔE if stained cloth compared to white original ΔE of black cloth compared to original Control (irradiation + rinse) 56.3 0.3 25gl^-1 soap only 50.4 0.5 25gl^-1 soap + Irgacure 184 34.0 3.5 50gl^-1 soap only 49.6 0.3 50gl^-1 soap + Irgacure 184 37.0 2.9 75gl^-1 soap only 56.0 0.4 75gl^-1 soap + Irgacure 184 38.6 2.2 100gl^-1 soap only 52.9 0.5 100gl^-1 soap + Irgacure 184 40.2 2.1 150gl^-1 soap only 44.1 0.5 150gl^-1 soap + Irgacure 184 41.0 1.3 1% Irgacure 184 from Ethanol -wet cloth - 11.3 1% Irgacure 184 from Ethanol -dry cloth - 4.0

Table 2 Stain bleaching and Dye damage from Irgacure 184 applied from C-14 soap solutions.

The experiment of example 2 were repeated except using 2gl-1 of the C-14 soap. The initiator did not dissolve in the solution and the solution was liquid.

0.2% initiator was dissolved in Genapol C-050 at room temperature. Water was added to this solution until the initiator precipitated. For both Irgacure 184 and Lucirin TPO-L precipitation occurred with less than 10% added water.

0.2% initiator was dissolved in Synperonic™ A20 at its melting point. Water was added to this solution until the initiator precipitated. For both Irgacure 184 and Lucirin TPO-L precipitation occurred with less than 10% added water.