Process for dyeing keratin fibres comprising a dye-pigment, a photoactive compound and a light source

Abstract

The invention relates to a process for dyeing and/or lightening keratin fibers using i) particular dye(s) and/or pigment(s), ii) photoactive compound(s) and iii) light source(s); a cosmetic composition comprising the ingredients i) and ii); the use of ii) for improving the fastness and/or dyeing and/or lightening of keratin materials in the presence of the ingredients i) and iii) of light source(s), and a multi-compartment device comprising i), ii) and iii). The implementation process and the use i) of particular dye(s) and/or pigment(s) combined with ii) the photoactive compounds and iii) with a light source make it possible especially to obtain lasting coloration on keratin fibers without the use of a reducing agent, and without odor.

Claims

1. A method for dyeing keratin fibers comprising: (i) applying to the fibers at least one dye and/or one pigment; (ii) applying to the fibers at least one photoinitiator; and (iii) exposing said keratin fibers to at least one light source wherein said at least one light source includes light emitted by diodes, optionally emitting one or more electromagnetic waves with a wavelength ranging from 10 nm in the ultraviolet (UV) region to 100 μm in the infrared (IR) region; wherein the at least one dye and/or pigment contains at least one photoreactive or photolabile group; wherein the steps may be performed together or separately; and wherein when the at least one dye and/or pigment contains at least one alkenyl or alkynyl photoreactive group, the presence of the photoinitiator is optional.

2. The method of claim 1, wherein the at least one dye and/or pigment is chosen from the direct dyes of formula (I) below:
A.sub.1-(X.sub.1).sub.p—R.sub.a1  (I) the organic or mineral acid or base salts thereof, optical isomers thereof, geometrical isomers and tautomers thereof, and solvates thereof; wherein: A.sub.1 represents a radical containing at least one anionic, cationic, zwitterionic or neutral colored chromophore; R.sub.a1 represents a group chosen from: i) optionally substituted (C.sub.4-C.sub.20)alkenyl or optionally substituted (C.sub.4-C.sub.20)alkynyl; X.sub.1 is chosen from: linear or branched, saturated or unsaturated divalent C.sub.1-C.sub.30 hydrocarbon-based chains, optionally interrupted and/or optionally terminated at one or both of its ends with one or more divalent groups or combinations thereof chosen from: —N(R)—; —N.sup.+(R)(R′)—, Q.sup.−; —O—; —S—; —S(O)—, —S(O).sub.2—, —C(O)—; —S(O).sub.2— with R and R′, independently chosen from hydrogen atoms and C.sub.1-C.sub.4 alkyl, hydroxy(C.sub.1-C.sub.8)alkyl or amino(C.sub.1-C.sub.8)alkyl radicals, and Q.sup.− represents an organic or mineral anionic counterion; aromatic or non-aromatic, saturated or unsaturated, fused or non-fused (hetero)cyclic radicals optionally comprising one or more identical or different, optionally substituted heteroatoms; and p is chosen from an integer equal to 0 or 1.

3. The method of claim 2, wherein the at least one dye and/or one pigment is chosen from the direct dyes of formula (I) wherein the chromophore A.sub.1 is chosen from those derived from (poly)azo, hydrazono dyes, (poly)methine dyes, and naphthalimides.

4. The method of claim 2, wherein the at least one dye and/or one pigment is chosen from the direct dyes of formula (I) wherein the chromophore A.sub.1 is fluorescent and chosen from those derived from (poly)methine dyes, comprising: the (poly)methines of formulae (XVIIIa) and (XIXa):
W.sup.+-[C(R.sup.c)═C(R.sup.d)].sub.m′-Ar′-(*)Q.sup.−  (XVIIIa)
Ar-[C(R.sup.d)═C(R.sup.c)].sub.m′-W′.sup.+-(*)Q.sup.−  (XIXa) wherein: W.sup.+ is chosen from a cationic heterocyclic or heteroaryl group; W′.sup.+ representing a divalent heterocyclic or heteroaryl radical as defined for W.sup.+; Ar is chosen from an aryl group, optionally substituted with i) one or more halogen atoms; ii) one or more groups (C.sub.1-C.sub.8)alkyl, iii) one or more hydroxyl groups; iv) one or more (C.sub.1-C.sub.8)alkoxy groups; v) one or more hydroxy(C.sub.1-C.sub.8)alkyl groups, vi) one or more amino or (di)(C.sub.1-C.sub.8)alkylamino groups, vii) one or more acylamino groups; viii) one or more heterocycloalkyl groups; Ar′ is a divalent aryl radical as defined for Ar; m′ represents an integer between 1 and 4 inclusive; R.sup.c and R.sup.d are independently chosen from hydrogen atoms or optionally substituted group (C.sub.1-C.sub.8)alkyls, or alternatively R.sup.c contiguous with W or W′ and/or R.sup.d contiguous with Ar or Ar′ form, with the atoms that bear them, a (hetero)cycloalkyl; Q.sup.− is an organic or mineral anionic counterion; and (*) represents the part of the chromophore linked to the rest of formula (I).

5. The method of claim 2, wherein the at least one dye and/or pigment is chosen from the direct dyes of formula (I) wherein p is equal to 1, at least one of the radical X.sub.1 represents the following sequence:
-(T).sub.t-(Z).sub.z-(T′).sub.t′- said sequence being linked in formula (I), as follows:
(A.sub.1)-(T).sub.t-(Z).sub.z-(T′).sub.t′-R.sub.a1; wherein: T and T′ are independently chosen from one or more radicals or combinations thereof chosen from: —S(O).sub.2—; —O—; —S—; —N(R)—; —N.sup.+(R)(R.sup.o)—, Q.sup.−; —C(O)—; wherein R and R.sup.o are independently chosen from hydrogen atoms, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 hydroxyalkyl or aryl(C.sub.1-C.sub.4)alkyl radicals and Q.sup.− represents an organic or mineral anionic counterion; and a cationic or non-cationic, monocyclic heterocycloalkyl or heteroaryl radical; the indices t and t′ are independently chosen from 0 or 1; Z represents: —(CR.sub.1R.sub.2).sub.m— with m being an integer between 1 and 8 inclusive and R.sub.1 and R.sub.2, independently chosen from hydrogen atoms or group (C.sub.1-C.sub.4)alkyl, (C.sub.1-C.sub.4)alkoxy, hydroxyl, cyano, carboxyl or (di)(C.sub.1-C.sub.4)(alkyl)aminos, said alkyl radicals optionally forming, with the nitrogen atom that bears them, a 5- to 7-membered heterocycle, optionally comprising another nitrogen or non-nitrogen heteroatom; —(CH.sub.2CH.sub.2O).sub.q— or —(OCH.sub.2CH.sub.2).sub.q— wherein q is an integer between 1 and 15 inclusive; or a divalent arylene, (C.sub.1-C.sub.4)alkylaryl or aryl(C.sub.1-C.sub.4)alkyl radical being optionally substituted with at least one group SO.sub.3M with M representing a hydrogen atom, an alkali metal or an ammonium group, the ammonium being substituted with one or more identical or different, linear or branched (C.sub.1-C.sub.4)alkyl radicals, optionally substituted with one or more hydroxyl groups; and z is 0 or 1.

6. The method of claim 2, wherein the at least one dye and/or pigment are chosen from the direct dyes of formulae (1a) to (1n) below: ##STR00094## and the organic or mineral acid or base salts, optical isomers, geometrical isomers and tautomers thereof and solvates thereof; wherein: R.sub.a1 represents a group chosen from: i) optionally substituted (C.sub.4-C.sub.20)alkenyl or optionally substituted (C.sub.4-C.sub.20)alkynyl; X.sub.1 is chosen from: linear or branched, saturated or unsaturated divalent C.sub.1-C.sub.30 hydrocarbon-based chains, optionally interrupted and/or optionally terminated at one or both of its ends with one or more divalent groups or combinations thereof chosen from:  —N(R)—; —N.sup.+(R)(R′)—, Q.sup.−; —O—; —S—; —S(O)—, —S(O).sub.2—, —C(O)—; —S(O).sub.2— with R and R′, independently chosen from hydrogen atoms and C.sub.1-C.sub.4 alkyl, hydroxy(C.sub.1-C.sub.8)alkyl or amino(C.sub.1-C.sub.8)alkyl radicals, and Q.sup.− represents an organic or mineral anionic counterion;  aromatic or non-aromatic, saturated or unsaturated, fused or non-fused (hetero)cyclic radicals optionally comprising one or more identical or different, optionally substituted heteroatoms; p is chosen from an integer equal to 0 or 1; G is chosen from a group —NR.sub.cR.sub.d or (C.sub.1-C.sub.6)alkoxy; R.sub.a and R′.sub.a, are independently chosen from optionally substituted (C.sub.1-C.sub.6)alkyl groups; R.sub.b is chosen from a hydrogen atom or an optionally substituted C.sub.1-C.sub.6 alkyl group; R.sub.c and R.sub.d are independently chosen from hydrogen atoms, aryl(C.sub.1-C.sub.4)alkyl or (C.sub.1-C.sub.6)alkoxy groups or (C.sub.1-C.sub.6)alkyl groups which are optionally substituted; or two adjacent radicals R.sub.c and R.sub.d, borne by the same nitrogen atom, together form a heterocyclic or heteroaryl group; R.sub.g, R′.sub.g, R.sub.h and R′.sub.h, are independently chosen from hydrogen atoms, halogen atoms, di(C.sub.1-C.sub.4)(alkyl)amino, cyano, carboxyl, hydroxyl or trifluoromethyl groups, acylamino, (C.sub.1-C.sub.4)alkoxy, (poly)hydroxy(C.sub.2-C.sub.6)alkoxy, (C.sub.1-C.sub.4)alkylcarbonyloxy, (C.sub.1-C.sub.4)alkoxycarbonyl, (C.sub.1-C.sub.4)alkylcarbonylamino, acylamino, carbamoyl or (C.sub.1-C.sub.4)alkylsulfonylamino radicals, aminosulfonyl radicals, or (C.sub.1-C.sub.16)alkyl radicals optionally substituted with a group chosen from (C.sub.1-C.sub.6)alkoxy, hydroxyl, cyano, carboxyl and di(C.sub.1-C.sub.4)(alkyl)amino, or the two alkyl radicals borne by the nitrogen atom of the amino group form a 5- to 7-membered heterocycle optionally comprising another nitrogen or non-nitrogen heteroatom; or alternatively two groups R.sub.g and R′.sub.g; R.sub.h and R′.sub.h borne by two adjacent carbon atoms together form a benzo or indeno ring, a fused heterocycloalkyl or fused heteroaryl group; the benzo, indeno, heterocycloalkyl or heteroaryl ring being optionally substituted with a halogen atom, a (di)(C.sub.1-C.sub.4)(alkyl)amino, nitro, cyano, carboxyl, hydroxyl or trifluoromethyl group, an acylamino, (C.sub.1-C.sub.4)alkoxy, (poly)hydroxy(C.sub.2-C.sub.4)alkoxy, (C.sub.1-C.sub.4)alkylcarbonyloxy, (C.sub.1-C.sub.4)alkoxycarbonyl or (C.sub.1-C.sub.4)alkylcarbonylamino radical, an acylamino, carbamoyl or (C.sub.1-C.sub.4)alkylsulfonylamino radical, an aminosulfonyl radical, or a (C.sub.1-C.sub.16)alkyl radical optionally substituted with: a group chosen from (C.sub.1-C.sub.6)alkoxy, hydroxyl, cyano, carboxyl and (di)(C.sub.1-C.sub.4)(alkyl)amino, or alternatively the two alkyl radicals borne by the nitrogen atom of the amino group form a 5- to 7-membered heterocycle optionally comprising another nitrogen or non-nitrogen heteroatom or alternatively when G represents —NR.sub.cR.sub.d two groups R.sub.c and R′.sub.g; R.sub.d and R.sub.g; together form a saturated heteroaryl or heterocycle, optionally substituted with one or more groups (C.sub.1-C.sub.6)alkyl; R.sub.i, R.sub.j, R′.sub.j and R′.sub.i are independently chosen from hydrogen atoms, or group C.sub.1-C.sub.4 alkyls; or alternatively R.sub.i with R.sub.g, R′.sub.i with R.sub.h borne by two adjacent atoms, together form a (hetero)cycloalkyl group, particularly for (1a) and (1 b), R.sub.i with R.sub.g or R′.sub.i with R.sub.h form a cycloalkyl; R.sub.s represents a sulfonate radical (O).sub.2S(O.sup.−)—, M.sup.+ or a carboxylate radical —C(O)O.sup.−, M.sup.+ with M.sup.+ representing an organic or mineral cationic counterion; the amino groups of the compounds (1m) and (1n) are linked to the carbon atoms of the phenyl group in position 2, 3 or 4; R.sup.e, R.sup.f, R.sup.g and R.sup.h are independently chosen from hydrogen atoms or C.sub.1-C.sub.6 alkyl groups which are optionally substituted; R.sub.1, R.sub.2, R.sub.3 and R.sub.4 independently chosen from hydrogen atoms or a group (C.sub.1-C.sub.4)alkyl, (C.sub.1-C.sub.12)alkoxy, hydroxyl, cyano, carboxyl or (di)(C.sub.1-C.sub.4)(alkyl)aminos, said alkyl radicals optionally forming, with the nitrogen atom that bears them, a 5- to 7-membered heterocycle, optionally comprising another nitrogen or non-nitrogen heteroatom; t and t′ independently chosen from 0 or 1; T.sub.a and T.sub.b independently chosen from one or more radicals or combinations thereof chosen from —S(O).sub.2—, —O—, —S—, —N(R)—, —N.sup.+(R)(R.sup.o)-M.sup.−, —C(O)—, wherein R, R.sup.o, independently chosen from hydrogen atoms or radicals (C.sub.1-C.sub.4)alkyl, hydroxy(C.sub.1-C.sub.4)alkyl; or an aryl(C.sub.1-C.sub.4)alkyl, and M.sup.− represents an organic or mineral anionic counterion; ##STR00095## represents an aryl or heteroaryl group fused to the phenyl ring; or alternatively is absent from the phenyl ring; m and n independently chosen from an integer between 0 and 10 inclusive with m+n representing an integer between 1 and 10; and M′ represents an organic or mineral anionic counterion.

7. The process of claim 1, wherein the at least one dye and/or pigment is chosen from the following compounds: ##STR00096## ##STR00097## ##STR00098## wherein An.sup.− and M′ are independently chosen from anionic counterions.

8. The method of claim 1, wherein the photoactive compounds are chosen from the compounds of formula (VI), and organic or mineral acid salts thereof, optical or geometrical isomers or tautomers thereof, and solvates thereof: ##STR00099## wherein: R represents a group chosen from: i) (C.sub.1-C.sub.10)alkyl, which is optionally substituted; ii) (C.sub.1-C.sub.10)alkoxy, which is optionally substituted; iii) hydroxyl; iv) optionally substituted (hetero)aryl; v) (hetero)cycloalkyl, which is optionally substituted; vi) R.sup.4—(X).sub.n—C(X)—(X).sub.n′- with R.sup.4 representing an optionally substituted (C.sub.1-C.sub.10)alkyl, optionally substituted (hetero)aryl, or optionally substituted (hetero)cycloalkyl group, n and n′ independently chosen from 0 or 1; vii) R.sub.cR.sub.dP(X)— with R.sub.c representing an optionally substituted (C.sub.1-C.sub.10)alkyl or optionally substituted (hetero)aryl group, and R.sub.d representing an optionally substituted (hetero)aryl group; viii) or alternatively R.sup.1 with R ortho to the group C(X)—R form, together with the atoms that bear them, a (hetero)cycle fused to the phenyl or (hetero)aryl fused to the phenyl, optionally substituted, with one or more oxo or thioxo groups; R.sup.1, R.sup.2 or R.sup.3 are independently chosen from hydrogen atoms, halogen atoms, optionally substituted (C.sub.1-C.sub.10)alkyl groups, (C.sub.1-C.sub.10)alkoxy optionally substituted especially with a hydroxyl group, optionally substituted (hetero)aryl, optionally substituted (hetero)cycloalkyl, carboxyl, cyano, nitro, nitroso, —S(O).sub.p—OM with p equal to 1 or 2, M representing a hydrogen atom or an alkali metal or alkaline-earth metal, R.sup.4R.sup.5N—; R.sup.4—(X).sub.n—C(X)—(X).sub.n′- with R.sup.4, n and n′ independently chosen from 0 or 1, R.sup.5 is as defined for R.sup.4 or alternatively R.sup.4 and R.sup.5 form, together with the nitrogen atom that bears them, an optionally substituted heterocycloalkyl or heteroaryl, which may be identical or different, being equal to 0 or 1; hydroxyl; or thiol; or alternatively contiguous R and R.sup.1 form, together with the carbon atoms that bear them, an optionally unsaturated and optionally substituted (hetero)cycloalkyl group; or alternatively two contiguous substituents R.sup.1, R.sup.2 together form a group derived from maleic anhydride; and X is independently chosen from oxygen or sulfur atoms or a group NR.sup.5 with R.sup.5 as defined previously.

9. The method of claim 1, wherein the at least one photoinitiator is chosen from the following compounds: benzophenone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, methyl 2-benzoylbenzoate, 4-ethyl 4-(dimethylamino)benzoate, 2-ethylhexyl p-(dimethylamino)benzoate, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-2-(phenylmethyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, ethyl 2-[2-oxo-2-phenylacetoxyethoxy]oxyphenylacetate, 2-[2-hydroxyethoxy]ethyl oxyphenylacetate, hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl-2-methyl-2-propanone, 4,4′-bis(diethylamino)benzophenone, (1-hydroxycyclohexyl)phenylmethanone, phenyl(2,4,6-trimethylphenyl)methanone, 4-phenylbenzophenone, 2-(dimethylamino)ethyl benzoate, 2,2-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2,2-dimethoxy-2-phenylacetophenone, methyl 2-benzoylbenzoate, 2-benzyl-2-(dimethylamino)-4-morpholinobutyrophenone, 1-phenyl-2-[O-(ethoxycarbonyl)oxime] 1,2-propanedione, 4-(dimethylamino)-2-butoxyethyl benzoate, 1-[4-(1,1-dimethylethyl)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-methyl-1-[(4-methylthio)phenyl]-2-(4-morpholinyl)-1-propanone; and organic or mineral acid salts thereof, optical or geometrical isomers or tautomers thereof, and solvates thereof.

10. The method of claim 1, wherein the at least one light source emitting one or more electromagnetic waves with wavelengths of between 10 nm in the UV region and 100 μm in the IR region comprise natural sunlight or daylight; lamps emitting in the UV region, incandescent lamps, halogen lamps, fluorescent lamps, mercury lamps, low-pressure lamps, high-pressure lamps, halide lamps, flash lamps, fluorescent excimer lamps, light-emitting diodes of 50 to 1000 mW, lamps emitting black light or Wood's light, and lasers.

11. The method of claim 1, which does not use at least one of a reducing agent and a chemical oxidizing agent.

12. The method of claim 1, further comprising a pre-treatment of keratin fibers with reducing agent when the dye contains at least one photoreactive group chosen from alkenyl or alkynyl groups.

13. The method of claim 1, wherein a reducing agent is not employed when the dye does not contain a photoreactive group chosen from alkenyl or alkynyl groups.

Description

EXAMPLES

I—Examples of Synthesis

Example 1

(1) Synthetic Scheme

(2) ##STR00086##

(3) Step 1

(4) ##STR00087##

(5) 4-Picoline (5 ml) is added to a three-necked flask equipped with a magnetic stirrer, a condenser and a bubbler. The alkene is added to the 4-picoline using a dropping funnel. At the end of the addition, the reaction mixture is heated at 80° C. for 2 hours. Ethyl acetate (200 ml) is added and the powder is then triturated to obtain a grey powder (11 g). The analyses are in accordance with the expected structure.

(6) Step 2

(7) The aldehyde is dissolved in 30 ml of isopropanol in a 250 ml three-necked flask equipped with a magnetic stirrer, a thermometer, a condenser and a bubbler. Pyrrolidine (2.02 g) diluted with isopropanol (10 ml) is added and the mixture is left stirring at room temperature (RT) for 15 minutes. Acetic acid (1.71 g) is added and an exotherm from 24° C. to 30° C. is observed with the appearance of white fumes in the reaction mixture. The mixture is allowed to cool to room temperature and the product from step 1 suspended in isopropanol (50 ml) is then added. The beaker containing the suspension is rinsed with isopropanol (10 ml) and added to the reaction mixture. The resulting mixture is stirred at room temperature for 24 hours. The product is evaporated to dryness and then purified by chromatography to obtain a shiny black powder.

(8) ##STR00088##

(9) Step 3: Counterion Exchange

(10) ##STR00089##

(11) The product bearing a bromide counterion is dissolved in methanol (30 ml) and then placed on a column of silica (C.sub.18). Water saturated with sodium chloride (500 ml) is passed through, followed by distilled water (500 ml). The product bearing a chloride counterion is desorbed with isopropanol, filtered off and then evaporated to dryness to obtain a shiny black powder (2.9 g). The analyses are in accordance with the expected structure.

II—Example of Dyeing

(12) II-1) Process for Dyeing with Dyes Bearing an Alkenyl Group and Comparative Dyes Structure of the Dyes

(13) TABLE-US-00003 Structure of the dyes Dye 13 0 Dye A* (compar- ative) Dye B* (compar- ative) (*)The synthesis of these comparative dyes is well known to those skilled in the art. Bibliographic references include: Dyes and Pigments (2008), 77(3), 678-685; Optical Materials (Amsterdam, Netherlands) (2008), 30(10), 1607-1615; CN 101424055; Journal of Applied Polymer Science (2009), 113(3), 1448-1453; CN 101424055.

(14) Step 1: Pretreatment of Keratin Fibres: Pre-Reduction of Hair

(15) The hair is pre-reduced with a Dulcia Vidal DV2® reducing solution in a ratio of 2 g of DV2 (pure) per lock of 1 g (9:1 V/V) extemporaneously, followed by application to locks of natural grey hair containing 90% white hairs at a rate of 5 g of formula per 1 g of hair, at room temperature for 10 minutes. The locks are then wrung dry, and then dyed.

(16) Step 2: Dyeing of Keratin Fibres

(17) A solution of the dye at 2 g % in distilled water is applied to the pre-reduced hair at a rate of 5 g of formula per 1 g of hair, at room temperature for 30 minutes. During dyeing. The hair is exposed to UVB radiation (wavelength of 312 nm) with a total amount of UVB of 7 J/cm.sup.2, and the lamp wavelength is 312 nm. The locks are then wrung dry and washed with a standard shampoo (0.4 g of shampoo/g of lock). Repetitive shampooing is performed, with drying for 30 minutes under a hood between two shampoo washes.

(18) Results:

(19) After dyeing, the colour of the locks is measured with a Minolta CM2600d spectrocolorimeter (specular components included, 10° angle, illuminant D65) in the CIE L*a*b* system. In this system, L* represents the intensity of the colour, a* indicates the green/red colour axis and b* the blue/yellow colour axis.

(20) ΔE represents the variation in colour between a lock of “pre-shampooed” hair and a lock of “post-shampooed” dyed hair, and is determined from the following formula:
ΔE=√{square root over ((L*−L.sub.o*).sup.2+(a*−a.sub.o*).sup.2+(b*−b.sub.o*).sup.2)}
in which L*, a* and b* represent the values measured on the “pre-shampooed” lock and L.sub.0*, a.sub.0* and b.sub.0* represent the values measured on the “post-shampooed” lock.

(21) The higher the value of ΔE, the less remanent the coloration with respect to successive shampooing.

(22) The colorimetric results obtained are given in the table below.

(23) TABLE-US-00004 ΔE measured after 10 shampoo washes Dye A (comparative) 24.69 Dye B (comparative) 25.06 Dye 13 (invention) 5.56

(24) It is seen from the above table that the coloration of the keratin fibres obtained with dye 13 according to the invention, after 10 shampoo washes, is much more resistant than the colorations produced with the comparative dyes A and B.

(25) II-2) Process for Dyeing with Disulfide Dyes and Comparative Dyes

(26) Comparative tests of dyeing keratin fibres were performed with the following dye:

(27) ##STR00093##

(28) Two Protocols were Evaluated and Compared Protocol 1: Application of the dye after a reducing treatment (outside the invention as described in patent application EP 1 647 580): The process comprises a pretreatment with a reducing agent capable of reducing the disulfide bonds of the hair. The reducing agent is chosen, for example, from thiols, for example thioglycolic acid. This pretreatment lasts for 15 minutes. The dye composition is applied at room temperature for 30 minutes. The application of the dye composition is followed by an oxidative post-treatment step for several minutes to fix the dyes to the hair. The oxidizing agent may be any oxidizing agent conventionally used in the field, for example hydrogen peroxide. The content of oxidizing agent is generally between 1% and 40% by weight relative to the weight of the ready-to-use composition. Protocol 2: Application of the dye with a photoactive compound (invention)

(29) For each protocol, two locks are dyed. One lock is exposed to a light source (see below) during the dyeing and one lock is kept protected from light during the dyeing (by covering with aluminium foil).

(30) The light source is a sun simulator: (model 69920, LOT-Oriel, Palaiseau, France). The power of the light is 10 mW/cm.sup.2 (UV-A) and 4 mW/cm.sup.2 (UV-B).

(31) All the locks (natural hair containing 90% white hairs) are washed before use with an aqueous solution containing 2% by weight of sodium lauryl sulfate. The lock is taken in the hand containing 0.4 g/g of lock of sodium lauryl sulfate solution and the lock is passed between the fingers ten times to simulate shampooing. The lock is then rinsed thoroughly with tap water at 38° C. and then wrung dry to extract the maximum amount of water.

(32) Protocol 1: Application of the Dye Following a Reductive Pretreatment (Comparative)

(33) The locks of hair were reduced with a reducing treatment before applying the dye composition. This pretreatment consists in applying 5 g of L'Oréal Dulcia Vital 2-force1® (9% thioglycolic acid) per 1 g of hair, at room temperature for 15 minutes. The locks are rinsed with water and then drained dry before dyeing.

(34) The dye composition was prepared with the contents of ingredients given in the table below (composition 1):

(35) TABLE-US-00005 Ingredients Composition 1 Hydroxyethylcellulose Natrosol 250MR 0.72 g C.sub.8/C.sub.10 Alkyl (50:50) hydroxyethylcellulose CG 110 5 g Benzyl alcohol 4 g Polyethylene glycol 400 4 g Dye 1 0.5 g Water qs 100 g

(36) Composition 1 is applied to natural hair containing 90% white hairs, at a rate of 5 g of composition per 1 g of hair, at room temperature for 30 minutes. The locks are rinsed with water, drained dry and then soaked for 5 minutes in a hydrogen peroxide solution (10 vol.: 5 g of composition per 1 g of hair). The locks are then rinsed, washed with shampoo and dried under a hood for 30 minutes.

(37) Protocol 2: Application of Dye with a Photoactive Compound (Invention)

(38) The dye composition 2 was prepared with the contents of ingredients given in the table below:

(39) TABLE-US-00006 Ingredients Composition 2 Hydroxyethylcellulose Natrosol 250MR 0.72 g C.sub.8/C.sub.10 Alkyl (50:50) hydroxyethylcellulose CG 110 5 g Benzyl alcohol 4 g Polyethylene glycol 400 4 g Dye 1 0.5 g 4-(2-Hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone 0.5 g Photoactive compound Water qs 100 g

(40) Composition 2 is applied to natural hair containing 90% white hairs, at a rate of 5 g of composition per 1 g of hair, at room temperature for 30 minutes.

(41) The locks are then drained dry, and then washed with shampoo and dried under a hood for 30 minutes.

(42) Repetitive Shampooing Protocol

(43) All the locks (natural hair containing 90% white hairs) are washed before use with aqueous solution containing 2% by weight of sodium lauryl sulfate. The lock is taken in the hand containing 0.4 g/g of lock of sodium lauryl sulfate solution and the lock is passed between the fingers ten times to simulate shampooing. The lock is then rinsed thoroughly with tap water at 38° C. and then drained dry to extract the maximum amount of water. Repetitive shampooing is performed, with drying for 30 minutes under a hood between two shampoo washes.

(44) Measurements of the Visibility of the Coloration and of the Remanence of the Visibility

(45) After dyeing, the colour of the locks is measured with a Minolta CM2600d spectrocolorimeter (specular components included, 10° angle, illuminant D65) in the CIE L*a*b* system. In this system, L* represents the intensity of the colour, a* indicates the green/red colour axis and b* the blue/yellow colour axis.

(46) The higher the value of L*, the less intense the coloration.

(47) ΔE shampoo represents the variation in colour between a lock of dyed hair before repetitive shampooing and a lock of dyed hair after repetitive shampooing, and is determined from the following formula:
ΔEshampoo=√{square root over ((L.sub.o*−L.sub.1*).sup.2+(a.sub.o*−a.sub.1*).sup.2+(b.sub.o*−b.sub.1*).sup.2)}
in which L.sub.0*, a.sub.0* and b.sub.0* represent the values measured on the “pre-repetitive shampooing” lock and L.sub.1*, a.sub.1* and b.sub.1* represent the values measured on the “post-repetitive shampooing” lock.

(48) The higher the value of ΔEshampoo, the less remanent the coloration with respect to successive shampooing.

(49) Results

(50) The colorimetric results obtained are given in the table below.

(51) TABLE-US-00007 L* before repetitive Dyeing protocol shampooing ΔE.sub.shampoo protocol 1 without light 31.98 8.38 protocol 1 with light 29.06 10.67 protocol 2 without light 29.83 7.32 protocol 2 with light (invention) 28.42 4.71

(52) The results show that: the coloration obtained using protocol 1 and protocol 2 with or without exposure to light are of similar intensity (L*). the coloration obtained using protocol 2 with exposure to light and after 10 shampoo washes (repetitive shampooing) is much more resistant than the colorations performed using the comparative protocols.

(53) During the coloration and shampooing using protocol 1, an unpleasant odour is noted. During the coloration and shampooing using protocol 2, no odour is noted.