GB2186889A

GB2186889A - Colouring keratinous material

Info

Publication number: GB2186889A
Application number: GB08604705A
Authority: GB
Inventors: Petrina Felecity Fridd; Rosemary Margaret Taylor
Original assignee: Dow Corning Ltd; Dow Corning Corp
Current assignee: Dow Silicones UK Ltd; Dow Silicones Corp
Priority date: 1986-02-26
Filing date: 1986-02-26
Publication date: 1987-08-26
Also published as: JPS62209015A; GB2186890B; GB8700620D0; GB8604705D0; JPH039086B2; GB2186890A

Abstract

A process for colouring hair in which certain silicone products are employed to provide improved depth of colour and colour retention is disclosed. Preferably the silicone products are employed as a pretreatment on hair prior to application of colorant. The silicone products are polysiloxanes including siloxane units having a silicon-bonded hydroxyl group or a nitrogen containing group attached to a silicon atom through an alkylene group. Polysiloxanes exemplified are according to the average general formulae HO(Me2SiO)xH in which x has a value of about 1100 +/- 100, HO(SiMe2O)x(OHR'SiO)yMe2SiOH in which the ratio x DIVIDED y is approximately 100 and R' represents -(CH2)3NH(CH2)2NH2, Me3SiO(Me2SiO)98(MeR'SiO)2SiMe3 in which R' represents -CH2(CH(CH3)CH2NH(CH2)2NH2, MeSiO(Me2SiO)98(MeR'SiO)2SiMe3 in which R' represents -CH2CH(CH3)CH2NH(CH2NH(CH2)2NH2, MeSiO(Me2SiO))96(MeR'SiO)2SiMe3 in which R' represents -(CH2CH(CH3)CH2N(COCH3)(CH2)2NHCOCH3, MeSiO(Me2)96(MeR'SiO)2SiMe3 in which R' represents -CH2CH(CH3)CH2NH(CH2)2NHCOCH3, and Me3SiO(Me2SiO)95(MeR'SiO)5SiM3 in which R' represents -(CH2)3N (Me2)(CH2)12Cl.

Description

SPECIFICATION Colouring keratinous material The present invention is concerned with colouring keratinous material and is particularly concerned with colouring human hair.

Human hair comprises fibres which have a layer of flat scales pointing outward from root to tip. Although the individual scales are thin, they are long and overlap each other forming a continuous, multilayered shield around the fibre. Within this shield lies hair cortex which constitutes the bulk of the hair. Dispersed throughout the cortex are pigment particles called melanin.

Their number and distribution patterns determine the hair colour.

Hair is composed almost entirely of keratin i.e. cystine-containing proteins. It is understood that the two main protein fractions are low- and high-sulphur proteins. The low-sulphur fraction consists of proteins of high molecular weight and high degree of molecular organization (ez- helical) whereas the high-sulphur proteins are of low molecular weight and do not exhibit any regular secondary structure. Both proteins participate in a composite filament-matrix texture which is the dominant structural element of hair cortex. The filaments are composed of lowsulphur proteins and the surrounding matrix is made up of high-sulphur proteins. The chemical composition of the scales differs from that of the fibre and scale cells do not apparently contain any low-sulphur proteins.The exposed portion of each scale is heavily cross-linked by cystine and this fact, in conjunction with the multilayered shield effect, makes the scales a formidable barrier to penetration by chemicals to the interior of the hair fibre.

It is a practice to modify the colour of human hair by the use of hair colorants containing dyes. These hair colorants may be divided conveniently into those which give "permanent", "semi-permanent" or "temporary results". By "permanent" is meant that the result of the colouring process remains fast to the action of shampoos, perspiration, sunlight and mechanical abrasion until the hair grows out. By "semi-permanent" is meant that the result of the colouring process remains fast to the action of shampoos, perspiration, sunlight and mechanical abrasion for approximately 6 to 10 washings with shampoo. By "temporary" is meant that the result of the colouring process may be removed in from one to three shampooings.

In permanent hair colorants the dyes used (at least until recent years) have been predominantly of the oxidation type whereby a water insoluble coloured material is produced inside the hair fibre as a result of oxidation of colourless intermediates which penetrate the cortex. The colour forming reactions are accomplished by primary intermediates, secondary intermediates and oxidants. Primary intermediates include for example p-phenylene-diamine, p-toluenediamine, p-aminodiphenylamine and o,p-aminophenol, p-amino-o-cresol, toluene 2,5 diamine, N-phenyl-p-phenylenediamine, pyrogallol, 4,4'-diaminodiphenylene-diamine, p-methylaminophenol, o-phenylenediamine, toluene 3,4 diamine, p-chloro-o-phenylenediamine, o-chloro-p-phenylenediamine and 2,6 diaminopyridine.The secondary intermediates, also known as couplers or modifiers, are used in conjunction with the primary intermediates to produce dyes. Secondary intermediates include for example m-aminophenol, resorcinol, m-phenylendiamine, hydroquinone, resorcine, catechol, toluene 2,4 diamine, 1-naphthol, 4-methoxy-m-phenylene-diamine or alphanaphthol and polyhydroxyphenols. It is believed that the initial oxidation product of p-phenylenediamine for example is benzoquinone diimine. It may react with p-phenylenediamine to form a dye but the diimine reacts much faster with secondary intermediates to form a variety dyes. By selection of appropriate intermediates, various colours may be achieved. The oxidant (otherwise known as the developer) e.g. hydrogen peroxide, sodium perborate, urea peroxide or sodium percarbonate, is usually mixed with the dye intermediates just before use.In addition to its function in relation to the dye intermediates hydrogen peroxide may exert influence on the colouring of the hair by bleaching the melanin. Autoxidative dyes have also been proposed with a view to avoiding addition of separate oxidant.

It is a practice to include in permanent hair colorants nitro dyes which dye the hair without oxidation e.g. nitro derivatives of aminophenols and benzenediamines, for example nitro-p-phenylenediamine, p-nitro-o-phenylenediamine, 4-nitro-o-phenylenediamine, 2-amino-4-nitrophenol, 2amino-5-nitrophenol, picramic acid, 1,4 diaminoanthraquinone and picric acid. The nitro dyes and also anthraquinone dyes and azobenzene dyes are also commoniy used for semi-permanent hair colorants. For example nitrophenylene diamines and nitroaminophenols provide a range of yellow, orange, red and violet colours and amino-anthraquinones provide blue colours.Dyestuffs which may be employed for permanent or semi-permanent hair colorant systems also include for example plant hair dyes, for example those derived from henna, walnut or soybean and metallic hair dyes for example those which employ insoluble salts of for example iron, copper, lead, manganese, nickel or cadmium.

It is a practice to include in permanent and semi-permanent hair colorant compositions not only water and the dye or dye intermediates but also surfactants (to enhance wetting, cleansing, spreading and viscosity control) for example ammonium oleate, alkanolamides, fatty alkyl sul phates, thickeners for example carboxy methyl cellulose, materials to promote diffusion of the dye into hair and materials for solubilizing the dyes. Conditioning agents may also be included.

Temporary hair colorants make use of generally higher molecular weight dyes which do not penetrate the hair structure significantly but rather become deposited on the surface. Dyestuffs which may be employed for temporary hair colorant systems include oxidation dyes, azo dyes, quinoline dyes, acridine dyes, azine dyes, oxazine dyes, indigoid dyes, anthraquinone dyes, stilkene dyes and thiazole dyes.Temporary hair colorant systems may also employ pigments, for example iron oxides, titanium dioxide or carbon black and may employ a binder, for example methacrylate, acrylate, vinylacetate or vinyl-pyrrolidone polymers or copolymers to assist in binding the hair colorant to the hair, together with dispersion media for example water, acetone, ionic or non-ionic surface active agents, lower alcohols, polyhydric alcohols, higher alcohols, fatty acids and liquid hydrocarbons with a view to ease of application of the colorant and desired texture of the coloured hair.

It is also a practice in the care of human hair to apply so-called conditioner compositions with a view to enhancing desired qualities of the hair for example ease of combing, detangling, body, shine, texture, split end mending prevention of static build up and general manageability. It has been proposed to include in conditioner compositions various silicone products, including for example emulsions of the amine functional silicone polymer amodimethicone. It has been for many years the normal practice to apply conditioner compositions, which may include for example one or more silicone polymers, to the hair after the operation of colouring the hair has been completed.

Surprisingly, we have now found that an improvement in the depth of colour of dyed hair and the period of time during which the colour is retained by dyed hair may be enhanced as a result of application to the hair of certain organofunctional silicones.

The present invention provides in one of its aspects in a method of colouring hair by means of a hair colorant system, the use of a polysiloxane comprising siloxane units having at least one organofunctional group provided by a silicon bonded hydroxyl group or a nitrogen containing group linked to a silicon atom by an alkylene group to enhance the depth of colour and/or prolong retention of the colour imparted to the hair by the hair colorant system.

In a method according to the invention the siloxane units having at least one organofunctional group preferably are according to the average general formula RaR'bSIO 4-(a+b) 2 wherein each R represents a monovalent hydrocarbon group, a hydrogen atom, an alkoxy group, an alkoxyalkoxy group or a carboxyl group, each R' represents a hydroxyl group or a nitrogen containing group which is a primary or secondary amino, an amido or a quaternary ammonium group according to one of the general formulae (i) -R"NAQ and (ii) -R"NtA2Q wherein R" represents an alkylene group comprising a chain of up to 5 carbon atoms, each A represents a hydrogen atom, an acyl group or an alkyl group, each Q represents a hydrogen atom, an alkyl group or a group according to one of the general formulae (i) and (ii), a has a value 0, 1, 2 or 3 and b has a value 1 or 2.

Preferably the group R is a hydrocarbon group. Suitable hydrocarbon groups include the lower alkyl and aryl groups, the methyl and phenyl groups, being the most preferred. There may be one or two groups R' present in siloxane units as aforesaid and these may be the same or different, for example one hydroxyl group and one nitrogen containing group. Suitable nitrogen containing groups according to the formula (i) include for example those according to the formulae (a) -(CH2)3NH(CH2)2NH2 (wherein R" is provided by -(CH2)3-, A is provided by a hydrogen atom and Q is provided by -(CH2)2NH2 i.e.R"NAQ in which R" is provided by -(CH2)2- and A and Q are each provided by a hydrogen atom) (b) -CH2CH(CH3)CH2NH(CH2)2NH2 (wherein R" is provided by -CH2CH(CH3)CH2- and A and Q are as for formula (a) above) (c) -CH2CH(CH3)CH2NA'(CH2)2NHCOCH3 (wherein R" is provided by -CH2CH(CH3)CH2-, A' is provided by a hydrogen atom or an acyl group -COCH3 and 0 is provided by -(CH2)2NHCOCH3 i.e.

R"NAO in which R" is provided by -(CH2)2-, A is provided by a hydrogen atom and 0 is provided by an acyl group). Suitable nitrogen containing groups according to the formula (ii) include for example those according to the formula (d) -(CH2)3N+(Me)2(CH2)rn (wherein R" is provided by -(CH2)3-, each A is provided by a methyl group and 0 is provided by an alkyl group having a chain of 12 to 20 carbon atoms).

The siloxane units comprising an organofunctional group may be present in the polysiloxane as terminal units or as chain units of the polymer and may provide any desired proportion of the total amount of siloxane units present in the polymer. However, in the example polymers hereinafter referred to the siloxane units comprising organofunctional units provide minor amounts of the total quantity of siloxane units, and in preferred materials are present to an extent of no more than about 2 to 5 percent of the total siloxane units.The other siloxane units of the polysiloxane are suitably siloxane units according to the general formula ZcSiO 4-c 2 wherein each Z represents a hydrocarbon group for example an alkyl group for example a methyl, ethyl or propyl group or an aryl group for example a phenyl group or an unsaturated aliphatic or alicyclic compound for example a vinyl or cyclohexenyl group. The value of c may be 0, 1, 2 or 3 and thus these units may provide terminal, chain or branching units in the polysiloxane chain.

In a method according to the invention the hair colorant system may be any of those conventionally used for the temporary, semi-permanent or permanent colouring of hair as referred to above. The hair colorant system may conveniently be water based and may include usual additives as referred to above. Various commercially available hair colorant systems may be employed in a method according to the invention, for example those supplied by Elida Gibbs under the trade name Harmony and those supplied by Bristol Myers and Clairol under the trade name Glints and Clairol respectively.

A method according to the invention may be carried out for example by first washing the hair using a conventional shampoo formulation comprising for example about 20% by weight sodium laurylethersulphate, rinsing it with town water and drying it to the towel dry stage and then applying the chosen polysiloxane in aqueous emulsion. The hair, after about one minute, may be brought again to the towel dry stage and the colorant system applied and left in place for about 15 to 20 minutes. The hair may then be rinsed to remove residual colouring matter and dried by forced hot air treatment. Alternatively, one may mix certain of the polysiloxane and colorant systems before application to the hair, but this is not preferred.

The invention provides in another of its aspects a method of colouring keratinous material comprising applying to the material a composition comprising a polysiloxane comprising siloxane units having at least one organofunctional group provided by a silicon bonded hydroxyl group or a nitrogen containing group linked to a silicon atom by an alkylene group and thereafter applying to the material a hair colorant system.

A method according to the invention may be employed in the colouring of virgin hair, or in the colouring of hair which has become damaged e.g. as a result of bleaching or of permanent waving, to provide the hair with an enhanced depth of colour. Using certain of the preferred materials one may also achieve a prolonged retention of the imparted colour as compared with other methods. In addition one may achieve some conditioning of the hair.

In order that the invention may become more clear there now follows a description of examples of the invention. In the examples, the symbol Me represents a methyl group and the symbol Ph represents a phenyl group. All proportions mentioned in the examples are by weight unless otherwise specified.

In the examples, various commercially available hair colorant systems were used strictly in accordance with their supplier's instructions to colour switches of virgin hair of European origin, portions of which had been bleached and portions of which remained unbleached, to provide coloured standard samples of bleached and unbleached virgin hair of each colour. Comparative samples of coloured hair were prepared from similar switches of virgin and bleached hair using control compositions or polysiloxane compositions as a pretreatment for the commercial hair colorant systems. The colour of the coloured bleached and unbleached portions of the samples was observed and compared shortly after the colouring operation and, for some samples, after several washes.Except where otherwise specified herein, the various commercially available hair colorant systems used were of the semi-permanent type.

Bleaching of portions of the virgin hair switches was carried out as follows. An end portion of each switch of virgin hair was dipped for two hours at room temperature in a solution formed by mixing equal parts by volume of solutions A and B. Solution A was a 50% by volume aqueous solution of hydrogen peroxide. Solution B was a mixture of 13.5 parts by volume ammonia (sp.gr 0.88) 3 parts by volume Empicol ESB 3 (a sodium lauryl ether sulphate) and 83.5 parts by volume water. After two hours, the hair was removed from the solution, rinsed in running water and then dried using air heated to 70"C.

Control composition 1 was a 0.35% solids aqueous solution of the quaternary ammonium salt cetalkonium chloride. Control composition 2 was a 0.35% solids aqueous solution of a polysiloxane polyoxyalkylene copolymer according to the average general formula (Me)3SiO(Me2SiO)x(MeR'- SiO)ySiMe3 where R' has the average general formula -C3H50(C2H40)n(CH3C2H30)mH as supplied by Dow Corning Limited under the trade name DC 193.

The polysiloxane compositions used were as follows: Polysiloxane 1 was an aqueous emulsion containing 0.35% solids of a hydroxyl terminated polydimethylsiloxane according to the average general formula HO(Me2SiO)xH in which x has a value of about 1 100+100.

Polysiloxane 2 was a cationic emulsion of pH about 7.6 of polydimethylsiloxanes having amine functionality and hydroxyl functionality according to the average general formula H0(SiMO20)x (OHR'SiO)y (x/y approximately 100) in which R' represents -(CH2)3NH(CH2)2NH2.

Polysiloxane 3 was a non-ionic aqueous emulsion of pH about 10.5 containing 0.35% of polydimethylsiloxane having amine functionality according to the average general formula Me 3SiO(Me2SiO)98(MeR'SiO)2SiMe3 in which R' represents -CH2CH(CH3)CH2NH(CH2)2NH2.

Polysiloxane 4 was a non-ionic aqueous emulsion of pH about 3.5 containing 0.35% of polydimethylsiloxane having amido groups according to the average general formula Me3SiO(Me 2SiO)96(MeR'SiO)2SiMe3 in which R' represents -CH2CH(CH3)CH2N(COCH3)(CH2)2 NHCOCH3.

Polysiloxane 5 was a non-ionic emulsion of pH about 9.2 containing 0.35% of polydimethylsiloxane having amido groups according to the average general formula Me3SiO(Me2SiO)96(MeR'SiO)2S- iME3 in which R' represents -CH2CH(CH3)CH2NH(CH2)2NHCOCH3.

Polysiloxane 6 was an aqueous solution containing 0.35% of polydimethylsiloxane having quaternary ammonium groups according to the average general formula (Me3SiO(Me2SiO)95(MeR'SiO)5S- iMe3 in which R' represents -(CH2)3N+(Me2)(CH2)12Cl-.

Examples 1 to 4 The various hair colorant systems, with and without pretreatment using control compositions and polysiloxane compositions, were employed to colour switches of bleached and unbleached virgin hair as aforesaid in the following way. The hair was shampooed using a 20% active sodium laurylether sulphate water based composition. The hair was rinsed and padded dry to a towel dry condition. The selected colorant, made up according to the supplier's instructions was applied to bleached and unbleached portions of the treated hair by covering the hair with the colorant for twenty minutes. The hair was rinsed in running water until the water was colourless.

The hair was dried in air heated to 70"C until the hair became dry. In those cases in which a pretreatment with a control or polysiloxane composition was employed, after the hair had been padded dry following the initial shampoo and rinse stages, the bleached and unbleached portions of the hair were dipped for one minute in the control composition or polysiloxane composition.

The hair was removed from the composition and padded dry to a towel dry condition. The selected colorant was then applied to the hair, the hair rinsed and dried as aforesaid. The colour of the bleached and unbleached portions of the samples was observed shortly after the hot air drying step.

Example 1 Control compositions 1 and 2 and polysiloxanes 1 to 6 were evaluated as pretreatments for hair colorant systems using products supplied by Elida Gibbs under the designation Harmony Auburn and Harmony Rich Chestnut using the method described above. By inspection of the samples coloured with Harmony Rich Chestnut it was found that the depth of colour of the coloured bleached and unbleached portions of the sample made using control composition 2 was the same as the depth of colour of the corresponding portions of the coloured standard, whereas control composition 1 gave slightly more depth of colour on the bleached and unbleached portions than the standard.In comparison, the samples made using each of the polysiloxane compositions 1, 2, and 3 had a greater depth of colour on the bleached and unbleached portions than the corresponding portions of the coloured sample made using control composition 1 , and the coloured bleached and unbleached portions of the samples made using polysiloxanes 4, 5 and 6 had a depth of colour similar to that of the bleached and unbleached portions of the sample made using control composition 1.

By inspection of the samples coloured with Harmony Auburn, it was found that the depth of colour of the coloured bleached and unbleached portions of the samples made using control compositions 1 and 2 were similar to each other and greater than the depth of colour of corresponding portions of the standard. In comparison, the samples made using each of the polysiloxane compositions 1, 2, 3, 4 and 6 had a greater depth of colour on their bleached and unbleached portions than the corresponding portions of the sample made using control composition 1 and the colour of the bleached and unbleached portions of the sample made using polysiloxane 5 had a depth of colour similar to the corresponding portions of the sample made using control composition 1. In conjunction with Harmony Auburn and in conjunction with Harmony Rich Chestnut, the coloured bleached and unbleached portions of the samples made using polysiioxanes 4 and 5 showed good depth of colour as compared with the corresponding portions of the corresponding standards and samples made using polysiloxanes 1 and 6 showed better depth of colour.

Example 2 Polysiloxanes 2 and 3 were evaluated as pretreatments for hair colorant systems using product supplied by Elida Gibbs under the designation Harmony Auburn and Harmony Rich Chestnut and by Bristol Myers and Clairol under the designation Glints Rosetip using the method described above. Using the polysiloxanes at a concentration to provide 0.1% of polysiloxane in the polysiloxane compositions, it was found that samples made using each of polysiloxanes 2 and 3 showed more depth of colour, both in the bleached portion of the switch and in the unbleached portion, with Harmony Auburn and Harmony Rich Chestnut than the corresponding portions of the coloured standards, polysiloxane 3 giving the better results with Rich Chestnut.Using the polysiloxanes at a concentration of 0.35% it was found that with Harmony Auburn and Glints Rosetip samples prepared using polysiloxane 2 gave better depth of colour, both in the bleached portion of the switch and in the unbleached portion, than the corresponding portions of the coloured standard, and polysiloxane 3 gave yet more depth of colour.

Example 3 Polysiloxane compositions 1 to 6 were evaluated as pretreatments for hair colorant systems using Harmony Auburn and Harmony Rich Chestnut (the polysiloxane compositions being used at a concentration of 0.35% polsiloxane) using the method described above. By inspection of the samples it was found that with Harmony Auburn the best depth of colour, both on bleached portions of the switch and on unbleached portions, was observed on samples in which polysiloxane 1, 2 or 6 had been used as pretreatment, wherein with Harmony Rich Chestnut the best depth of colour, both on bleached portions of the switch and on unbleached portions, was observed on samples in which polysiloxane 2, 3 or 4 had been used as pretreatment.

Example 4 Polysiloxane compositions 2 and 3 were evaluated as pretreatments for hair colorant systems using Harmony Auburn, Harmony Rich Chestnut, Harmony Midnight Auburn, Harmony Burnished Copper and Clairol Chestnut Brown (a permanent hair colorant system) using the method described above. It was found with each colorant system that samples made using pplysiloxane compositions 2 and 3 (at a concentration of 0.35% polysiloxane) showed an improved depth of colour, both on bleached and unbleached portions of the switch as compared with the corresponding standards.The depth of colour of the bleached and unbleached portions of samples treated with polysiloxane composition 2 was more noticeable than that of the corresponding portion of samples treated with polysiloxanes 3 in the case of samples treated with Auburn and Chestnut Brown, whereas samples prepared by pretreatment with polysiloxane 3 showed more depth of colour than those prepared by pretreatment with polysiloxane 2 in conjunction with Rich Chestnut and Burnished Copper. In the case of Chestnut Brown, the effect appeared to be associated with a reduction in a greenish tint present in the corresponding standard.

Example 5 Switches of bleached and unbleached virgin hair were coloured with Harmony Auburn and Harmony Rich Chestnut with and without pretreatment using the various polysiloxane and control compositions, using the method described in Examples 1 to 4. The coloured samples were subjected to wash cycles each involving washing the sample in 20% active solution of sodium lauryl ether sulphate water based composition, rinsing with clean water, a second wash in 20% active sodium lauryl ether sulphate, and a second rinse with clean water followed by drying with air heated to 70"C. After each wash cycle each sample was inspected and the colour noted. It was noted that some colour from each sample was washed out. The wash cycles were repeated until the colour on the bleached and unbleached portions of each comparative sample was the same as the colour of the corresponding portion of its washed standard counterpart.

The number of wash cycles completed prior to attaining this colour match is shown in the following table: Number of Washes to Match Sample Pretreatment Auburn Rich Chestnut Control 1 2 5 Control 2 3 0 Polysiloxane 1 2 7 Polysiloxane 2 3 0 Polysiloxane 3 3 4 Polysiloxane 4 3 11 Polysiloxane 5 3 4 Polysiloxane 6 9 5 These results indicate that in many cases hair coloured by a method according to the inven tion retain their colour through more shampooings than hair coloured without pretreatment using a polysiloxane and in two cases retain their colour to an oustanding degree.

Claims

1. In a method of colouring hair by means of a hair colorant system, the use of a polysiloxane comprising siloxane units having at least one organofunctional group provided by a silicon bonded hydroxyl group or a nitrogen containing group linked to a silicon atom by an alkylene group to enhance the depth of colour and/or prolong retention of the colour imparted to the hair by the hair colorant system.

2. A method of colouring keratinous material comprising applying to the material a composition comprising a polysiloxane comprising siloxane units having at least one organofunctional group provided by a silicon bonded hydroxyl group or a nitrogen containing group linked to a silicon atom by an akylene group and thereafter applying to the material a hair colorant system.

3. A method according to Claim 1 or Claims 2 wherein the siloxane units having at least one organofunctional group are according to the average general formula RaR'bSI0 4-(a+b) 2 wherein each R represents a monovalent hydrocarbon group, a hydrogen atom, an alkoxy group an alkoxyalkoxy group or carboxyl group, each R' represents a hydroxyl group or a nitrogen containing group which is a primary or secondary amino, an amido or a quaternary ammonium group according to one of the general formulae (i) -R"NAQ and (ii) -R"N+A2Q wherein R" represents an alkylene group comprising a chain of up to 5 carbon atoms, each A represents a hydrogen atom, an acyl group or an alkyl group, each 0 represents a hydrogen atom, an alkyl group, or a group according to one of the general formulae (i) and (ii), a has a value of 0, 1, 2 or 3 and b has a value or 1 or 2.

4. A method according to any one of the preceding claims wherein the polysiloxane is according to the average general formula HO(Me2SiOìxH in which x has a value of about 1 100+ 100.

5. A method according to any one of Claims 1, 2 and 3 wherein the polysiloxane is according to the average general formula (HO(SiMe,O),(OHR'SiO), in which the ratio x y is approximately 100 and R' represents -(CH2)3NH(CH2)2NH2.

6. A method according to any one of Claims 1, 2 and 3 wherein the polysiloxane is according to the average general formula Me3SiO(Me2SiO)98(MeR'SiO)2SiMe3 in which R' represents -CH2CH(CH3)CH2NH(CH2)2NH2.

7. A method according to any one of Claims 1, 2 and 3 wherein the polysiloxane is according to the average general formula Me3SiO(Me2SiOì96(MeR'SiOì2SiMe3 in which R' represents -CH2CH(CH3)CH2N(COCH3) (CH2)2NHCOCH3.

8. A method according to any one of Claims 1, 2 and 3 wherein the polysiloxane is according to the average general formula Me3SiO(Me2SiO)96(MeR'SiO)2SiMe3 in which R' represents -CH2CH(CH3)CH2NH(CH2)2NHCOCH3.

9. A method according to any one of Claims 1, 2 and 3 wherein the polysiloxane is according to the average general formula Me3SiO(Me2SiO) > 5(MeR'SiO)sSiMe3 in which R' represents -(CH2)3Nf (Me,) (Me2)(CH2),2CI~~.

10. A method according to any one of the preceding claims wherein the hair colorant system is a semi-permanent hair colorant.