FR2536993A1 - HAIR DYEING PROCESS AND PRESENTATION OF COMPOSITIONS FOR CARRYING OUT SAID METHOD - Google Patents

Abstract

HAIR DYEING PROCESS COMPRISING THE FOLLOWING STEPS: THE HAIR IS DYED IN CONTACT WITH AN AQUEOUS SOLUTION OF A METAL SALT THAT PROMOTES MELANOGENESIS IN HAIR. BEFORE OR AFTER THE STAGE MENTIONED ABOVE, THE HAIR IS IN CONTACT WITH A 5,6-DIHYDROXYINDOLE SOLUTION, THE HAIR IS RINSED BETWEEN THE TWO CONTACT STEPS, WE MAINTAIN CONTACT WITH THE SECOND SOLUTION USED UNTIL WHAT A DARKER COLOR DESIRED IS OBTAINED, THE HAIR IS RINSED OR SHAMPOOED, THE HAIR IS THEN IN CONTACT WITH A HYDROGEN PEROXIDE SOLUTION UNTIL THE DESIRED COLOR TONE IS OBTAINED AND THEN RINSE THE HAIR AGAIN.

Description

2536993.

  HAIR DYEING PROCESS AND PRESENTATION OF COMPOSITIONS

  FOR THE IMPLEMENTATION OF THIS PROCESS

  The present invention relates to a method for dyeing hair, in particular human hair and a presentation of compositions for

implementation of this process.

  The color of human hair is due to the presence, in its structure-

  ture, of discrete particles of natural pigments, melanins.

  The study of melanins and melanogenesis has intensified in the last forty years given the interest raised by dyeing hair with materials such that they most closely resemble natural materials contributing to hair color Biosynthesis

  of melanin, involves converting tyrosine to melanin into pas-

  health by dihydroxyphenylalanine (dopa) by a certain number of stages,

  including that of 5,6-dihydroxy-indole, up to melanin.

  Besides the fact that it is generally desirable to dye the hair in a simple manner and with a dye which is closest to the material which contributes to the natural coloring of the hair, the need also exists for a dye for the hair which can also may be used as a temporary hair dye that can be applied

  and removed at will safely and quickly.

  Patents have been issued which cover aspects of color

  turing hair with melanin precursors, e.g. tyrosine, L-dopa, L-dopa esters, and 5,6-dihydroxyindole: U.S. Patents 2,539,202, 2,875 769 and 3,698,852

  dealing with the use of L-dopa as a starting material

  vets from the United States of America N O 2 934 396, 3 194 734, and 3 993 436

  describe the use of 5,6-dihydroxy-indole as a starting material.

  The major drawbacks of these systems are the time required for the development of the color, the uncertainty of the development and the lack of control which it has and the need to add compounds such as

  p-phenylene diamine and various couplers for adjusting the hue.

  In the process described in United States Patent No. 2,934,396, the hair is first treated with an acidic or neutral solution of 5,6-dihydroxyindole, the excess solution is then wrung out and the applying a solution of an oxidizing agent or an agent inducing oxidation to the hair until the desired shade develops. In one of the methods described in the patent, oxygen or air is used. ambient, while the second solution contains a

  alkaline agent and an oxidation promoter based on cobalt or manga-

  Most often, however, it is customary to use an ammoniacal solution of an oxidizing agent such as hydrogen peroxide or an iodate, periodate or persulfate of an alkali metal of ammonium, etc. When

  develops the desired shade, the hair is rinsed, shampooed

  fist, rinsed again and dried.

  U.S. Patent No. 3,194,734 represents a definite improvement over U.S. Patent No. 2,934,396 mentioned above because in the oldest patent process, dyeing which consists in an oxidative polymerization of, 6dihydroxyindole into melanin acts in competition with an oxidative destruction of the dye in formation, which results in a waste of indole, the production of irregular results on the hair - and the fact that it is difficult determine when to end the process by rinsing The most recent patent therefore proposes a process in which an aqueous alkaline composition containing 5,6-dihydroxyindole and ammonia or an amine is brought into contact with the hair that the desired shade is obtained Or else certain methylated derivatives of 5,6-dihydroindole can be used in a two-step process to obtain lighter shades, the hair then being impregnated with first with an aqueous solution of this methylated derivative in solution of acidic or neutral p H, then are quickly dried and the color then develops in a second step by application of a solution

aqueous containing an oxidizing agent.

  The present invention is partly based on the discovery that, unlike the prior art where H 2 Q 2 or other oxidants are used,

  either in a separate step, or at the same time as 5,6-dihydroxy-

  indole, to get a variety of shades you can get results

  superiors using a metal salt to promote melanogenesis.

  It has now been discovered that a better variety of hues and more reliable hue development can be obtained, and if desired, improved temporary hair coloring using a hair dyeing process comprising the steps following:

  the hair to be dyed is brought into contact with a solution,

  venable an aqueous solution of a metal salt which promotes the formation of melanin from 5,6-dihydroxyindole, before or after the step mentioned above, the hair is brought into contact with a solution, suitably a aqueous solution of 5,6-dihydroxyindole, the hair is rinsed between the two stages of contacting, the contact with the solution used in second is maintained - until a darker desired color is obtained, it is rinsed the hair or we shampoo them, then we put the hair in contact with a solution of hydrogen peroxide for a maximum of 15 minutes, until the shade of

  desired color is obtained and then the hair is rinsed again.

  In a particularly suitable embodiment of the process of the present invention, this process comprises the following stages: the hair to be dyed is brought into contact with an alkaline solution, suitably an aqueous solution containing cupric ions, before or after the above-mentioned step, the hair is brought into contact with a solution, suitably an aqueous solution, of 5,6 dihydroxyindole, the hair is rinsed between the two contact steps, contact is maintained with the second solution used until that a darker desired color is obtained and the hair is rinsed or shampooed. If a color other than gray or black is desired, the shade is obtained with a subsequent treatment with H 202. see thus that a main distinction between the current process and all the proposals of the prior art for dyeing with 5,6-dihydroxyindole lies in all cases in that, except when the final color desired is black, the hair is first dyed until a

  gray or black color, and the desired final shade is developed ul-

  subsequently by lightening with the hydrogen peroxide solution.

  Another feature of the present invention is a kit

  hair dye comprising in a unique presentation, a plura-

  lity of containers: a first container contains an aqueous solution of

  p H alkali of an effective amount of a metal promoting the formation of.

  melanin from 5,6-dihydroxyindole, a second container contains a solution of 5,6-dihydroxyindole of p H acid, a space being reserved for the vapor above the solution in this second container and containing

  a non-oxidizing gas, a third container contains an alkaline agent, the-

  said space reserved for steam in said second container being of volume

  sufficient to receive the third container or the contents of this third

  the fifth container in this space reserved for steam, and a fourth container

  content contains a solution of hydrogen peroxide. Another feature of the present invention relates to a hair dye kit containing in a single presentation a plurality of containers: a first container contains an alkaline p H solution of an effective amount of a metal which promotes the formation of melanin

  from 5,6-dihydroxyindole, a second container contains a solution

  alkaline, a space being reserved for the vapor above the solu-

  tion in this second container, a third container contains a solution

  tion of an effective amount of 5,6-dihydroxyindole to an acid p H, said

  space reserved for steam in the second container being of sufficient volume

  fisant to receive the third container or the contents of this third

  container within this space reserved for steam, and a fourth container

  content contains a solution of hydrogen peroxide.

  According to yet another characteristic of the present invention,

  a hair dye kit includes in one presentation one more

  container reality: a first container contains a solution at p H al-

  hose containing an effective amount of copper, a second container contains a solution of an effective amount of 5,6-dihydroxyindole at p H acid, a space reserved for steam being maintained above the solution in this second container and containing a non-oxidizing gas, a third container contains an alkaline agent, said space reserved for

  vapor in said second container being of sufficient volume to re-

  receive the third container or the contents of this third container in

the space reserved for steam.

  According to another embodiment of the present invention, a

  hair dye kit includes in a single presentation a

  container reality: a first container contains a solution of p H al-

  hug containing an effective amount of copper, a second container

  contains an alkaline solution, a space being reserved for the Steam

  above the solution in this second container, and a third container contains a solution of an effective amount of 5,6-dihydroxyindole at p H acid, said space reserved for steam in the second container being of sufficient volume to receive the third container or the contents

  of this third container-within this space reserved for steam.

  In accordance with the present invention, unless a black or gray shade is desired, the hair dyed with melanin from 6dihydroxyindole is lightened with a solution containing peroxide

  of hydrogen As used in this description and its claims

  cations, the term "hydrogen peroxide" means hydrogen peroxide

  or any other ingredient which, in aqueous solution, forms hydrogen peroxide

  drogen such as, for example, urea peroxide This lightning step

  cisse or establishment of the shade of the color is different from the classic oxidizing treatment employed in the classic bleaching of the hair In the classic bleaching, the natural color of the hair is removed by bleaching when one wishes to color them in a shade which is more clear as the natural hair color In this case, the natural hair color is bleached over a longer period of time with a strong oxidizing solution which usually

  contains hydrogen peroxide with added persalts, increasing the ef-

  discoloration fet at a p H of about 10 This discoloration step tends

  generally to weaken or otherwise damage the hair In the

  lightening tape according to the present invention, the

  classic way to bleach, because the hydro peroxide solution

  gene used in the present invention does not contain promoters

  discoloration such as parsley, it is used appropriately

  ble at a p H less than 10, especially around 9 and thinning

  it only takes about 15 minutes for the lightest shades.

  Therefore, the oxidative step of lightening and developing color, according to the present invention, is considerably faster.

  than conventional bleaching and it is not used to push the

  clarification beyond the natural color of the hair or the color they had before the method according to the present invention is used Without wishing to be bound by the following explanation, it is believed that the

  difference in the lightening according to the present invention and the decoration

  Classical loration is attributable to the new dyeing stage according to the present invention In naturally colored hair the pigment

  of melanin is distributed throughout the cortex, i.e. the nucleus in-

  upper part of the hair shaft This means that during the bleaching of the natural melanin color of the hair with a strong bleaching agent such as hydrogen peroxide reinforced by the addition of persalts, a considerable time is necessary for the bleaching agent penetrates

  through the non-pigmented periphery or cuticle in the hair shaft.

  In the process according to the present invention, it is believed that the dye is placed mainly along the periphery of the hair shaft.

  and the lightening hydrogen peroxide does not require the pre-

  sence of per-compounds as promoters or prolonged exposure to reach and discolor the dye Because of the ex-

  shorter position and peripheral penetration, the lightning

  cement according to the present invention does not tend to damage or

  to weaken the hair as is the case with conventional bleaching.

  Furthermore, it is believed that the dyes produced in accordance with the present invention are unique in that the metal promoting

  melanogenesis forms a complex with the melanin formed during dyeing.

  The affinity of the complexed metal is considered to be greater for lamelanin than for hair keratin. The reactivity of the melanin / metal complex dye with hydrogen peroxide is therefore greater than that of melanin without the metal. This is deduced from the observation

  that the melanin / copper complex, -produced in accordance with the present in-

  vention, can be cleared with hydrogen peroxide faster than natural melanin, even if a copper salt is dissolved in the peroxide

  of hydrogen used to lighten natural melanin So not only

  The metal also promotes the formation of melanin in the dyeing step according to the present invention, but it is believed to contribute to the ease

  and the speed of the lightening step For this reason, we say

  the lightening step according to the present invention which can be completed in less than 15 minutes, from the conventional discoloration which is of a different nature and generally requires a good period of time

  more than twice as long and requires only bleach promoters

  tion are added to the hydrogen peroxide.

  Another characteristic of the present invention is therefore a complex dye for hair based on melanin as a new composition of matter, this dye being prepared by bringing the

  hair with a solution of 5,6-dihydroxyindole and, before or after testing

  tape we just talked about, bringing the hair into contact with a solution

a cupric salt.

  The method according to the present invention can also be used

  to dye hair that has been previously dyed with dyes

  tures for classic hair, permanent or semi-permanent For-

  as long as the original dye is stable to the thinning solution

  which is softer than conventional bleaching agents for che-

  want, the dyeing and lightening steps of the present process do not destroy the starting color of the hair within the limits of the time used here for the lightening, whether or not the starting color is the natural color of the hair Consequently, the hair colored by the present process can be re-lightened until this starting color, that this re-lightening takes place the following day

or much longer after.

  If the present process is intended to give the hair a shade lighter than the natural shade of the hair or lighter than that to which the hair has been dyed by conventional techniques, then the hair must, first of all be bleached until to a lighter shade or even completely discolored before using the method according to the present invention In this case, the lightening treatment according to the present invention can be pushed up to any shade which is darker than the shade initially obtained by bleaching and then the hair can be lightened to any intermediate shade or, if desired, the shade initially obtained

  by discoloration can be found.

  If the desired shade is a lighter shade, it is not necessary

  be able to dye the hair completely black, but it will be enough to push

  ser the dye to a more or less dark gray When the dye

  is then cleared in a later step, it will clear up ini-

  especially to a more or less dark brown tint depending on whether it has

  been, in the initial stage, pushed up to a more or less dark gray.

  Of all the melanogenesis promoters that have been tested, we have found

  that Cu 2 + was the only one to promote the formation of melanin until it

  final attention of an intense black color It appears that the other metallic promoters which have been tested do not help to push the dye

  only to more or less dark shades of gray In these experiences

  these, longer hair exposure or higher concentrations

  of the metal promoter have not resulted in any

  lie the depth of the color obtained.

  In the dyeing stage, the treatment of the hair with the solu-

  tion of the melanogenesis promoter can, in general, precede or follow

  treating the hair with the solution containing 5,6-dihydroxy-

  indole In general, a better color depth can be obtained when treatment with the promoter solution precedes contact with the 5,6-dihydroxyindole solution. It is believed that any metal ion or transition metal which is susceptible to promote melanogenesis suitable for this purpose These include, for example,

  solutions of iron, cobalt, manganese, copper, silver, titanium, zirco-

  nium, tantalum, chromium, nickel, palladium, platinum, gold mercury, cadmium t, zinc, tin, antimony, lead, bismuth, etc. The metal salts can be used alone or in mixtures Except for cupric solutions, -it has been found that '' it was generally necessary to use a chelating agent

  such as citric acid, citrate, ethylene diamine tetraaceous acid-

  tick, ascorbic acid and the like to keep the metal in solution.

  Terms such as "melanogenesis promoter", "metal salt

  favoring melanogenesis "and variants of these terms such as

  read in the present description and in its claims, mean

  solutions of one or more metals promoting the formation of color in the hair, within a maximum period of 20 minutes after the hair has been brought into contact with a solution of 5,6-dihydroxyindole Qu ' a given metal or that a given combination of metals may or may not act as a promoter of melanogenesis, this can be determined by routine experimentation e N testing its capacity to form a dye based on melanin in accordance with the method according to the

present invention.

  It has been found that the most suitable melanogenesis promoter

  was Cu 2 + providing considerably faster dyeing and

  so much to push the dye until the final obtaining of a solid black.

  While the Fe 2 + ion works well too, it is less preferred than the

  copper, because of solubility problems it presents at certain ni-

  calves of p H and for other considerations In addition, when the cupric ion is used at a p H of about 9 or more, suitably at a p H of 9.5, no chelating agent is used. is necessary, because we cannot find traces insoluble in the solution Suitably,

  monoethanolamine or other alkaline agents can be used

  Nitrogen such as other alkanolamines, ammonia, etc. to adjust the desired p H The alkaline hydroxides only work well if a chelating agent is also used to maintain the solution The basic p H also has l advantage of making the hair swell and this allows a better setting of the dye In the case where O is the cupric ion, it is clearly preferable to impregnate the hair first with the solution containing the ion cupric and, after rinsing or

  spin the hair, impregnate it with the solution containing 5,6-

  dihydroxyindole The intermediate rinsing or spinning of the surface of

  hair is necessary to prevent surface formation of colo-

  rant which can be removed by washing since you actually want a form

  dyeing within the hair shaft itself As used

  in the description and in the claims in this context, the term

  "rinsing" includes wringing, wiping and any other possible method of removing a solution from the surface of the hair. It takes about

  from 2 to 20 minutes to dye the hair to the depth of coat

  maximum possible when using a promoter based on mixed salt

  metal for melanogenesis; but when using the cupric ion, the time required is found to be the shortest of this already short time interval. It can therefore be seen that the use of the cupric ion provides a plurality of advantages in relation to and higher than what we

  can be obtained with other melanogen promoters.

  The solution containing 5,6-dihydroxyindole is found

  suitable for a p H of 8 or more Preferably, the p H should not

  pass 9.5, since the solutions are more and more unstable when lep H increases. When one has finished dyeing the hair black or gray, a shampoo is preferable to a simple rinsing for the reason that

  dye that may have formed on the surface of the hair may not remove

  mine by rinsing and can then be removed by rubbing the surface.

  A shampoo will remove this superficial dye and thus prevent its

friction elimination.

  The concentration of 5,6-dihydroxyindole is not critical, but it can suitably be used from about 0.5 to about 2% by weight of the solution for reasons of economy and proper control of the dyeing speed As indicated, the concentrations of the various

  ingredients are not critical So where a concentration is indicated

  cited in the description and in the claims as being a

  "effective quantity", this indication means that the quantity used is sufficient for the desired end. This end can be as diverse as a different depth of shade, greater savings in the price of the ingredients, different reaction rates, the stability of the solution and the like Regardless of the purposes, the effectiveness of the amount of an ingredient can be determined by experimentation

  routine All the percentages given in the description and in

  claims are by weight unless otherwise specified

very much.

  If the desired shade is other than black, then the colors

  want, after the dye and any shampoo are subjected to a lightening step by contacting with a dilute solution

  of hydrogen peroxide until the desired shade is obtained.

  Any suitable hydrogen peroxide solution useful for bleaching or lightening the hair can be used in this step, however it has been found that an H 202 concentration of from about 1% to about 6% is sufficient. lightening of hair from black or gray, the color will go through different shades that are becoming lighter and we can end the process by rinsing the hair when it has reached the shade we want The natural shade hair can be easily found when you no longer want to keep a previously darker shade The aqueous solution of hydrogen peroxide

  is suitably used at p H greater than 8, in a suitable way

  ble at p H 9 The relatively slow, but not too slow, speed of lightning

  curing of up to 15 minutes, provides sufficient control to the user who can stop at any desired shade or shade

  natural hair In this way, the reactions of dyeing and de-

  coloring which competed in the prior art and the incon-

  venients attached to it are removed to provide better

  more positive control over the whole process notwithstanding the fact that the

  ture either done in a salon or by the user.

  The method according to the present invention also allows the selective coloring of different parts of the hair to obtain places

  lighter, stripes and other special cosmetic effects.

  To maintain stability, the solution of 5.6-

  dihydroxyindole is maintained at an acid p H, advantageously at approximately 4.5.

  In addition, the acid p H solution should be maintained under anaerobic conditions, for example under nitrogen, the atmosphere above the solution in the bottle therefore being during the conditioning

  nitrogen more than air One way to solve this problem is to

  hold a small volume of nitrogen above the solution in the bottle, sufficient space to allow the addition of an alkaline agent before

  use This can however be inconvenient and it is therefore

  hold a solution, advantageously a concentrated solution, for example at 12.5%, such as an aqueous alcoholic solution or completely alcoholic

  5,6-dihydroxyindole in which it is easily soluble to placid in a small

  full container until you want to use it Immediately before use, the contents of this small bottle can be made into a larger bottle which may contain a pre-alkaline solution.

  thickened to obtain the immediate alkaline solution of 5,6-dihydroxyindole-

he

  Another way to do it is to

  hold the alkaline agent in a small pocket made of a selective material

  highly soluble and you can then drop the whole bag in

  the space above the acidified solution containing 5,6-

  dihydroxyindole to avoid the consumer needing to handle

  an alkaline agent which can be powerful Or, when we want to add

  ter a little concentrated solution of 5,6-dihydroxyindole acidified to an alkaline solution, then the first solution can be kept in a selectively soluble bag which can be entirely transferred into the aqueous alkaline solution to avoid that the user need

  pour liquid from one container into another.

  It has been found that by adding a small amount, for example, 1% by weight of a surfactant such as sodium lauryl sulfate to at least one of the solutions of metal and 5,6- dihydroxyindole,

  the flow properties of the compositions could be improved and

  cilitate their application - on the hair Similarly, we can reduce

  untimely coloring of the scalp and improving the softness properties

  solution flow by adding a small amount, for

  example of 0.5% by weight, of a thickener in both solutions

  tions, for example carbomer 40, polymer of acrylic acid crosslinked with a polyfunctional agent and sold by Goodrich Chemical Company under

  Carbopol 940 name Identity of other desirable agents for-adjus-

  ter flow properties can be determined by experimentation

  routine since these flow properties adjusting agents-

  are well known in the field of the formulation of hair treatment compositions - It is also known in the prior art of hair treatment compositions, that certain additives modifying

  the flow properties may be incompatible with certain

  positions It has been found, for example, that additives such as cocamido-

  propyl hydroxysulta Tne sold by Lonza Chemical Co under the name Lonzay-

  ne CS, and the hydroxypropylmethyl cellulose sold by Dox Chemical Co under the name of Methocel were apparently not compatible with the compositions according to the present invention since the resulting color is not as deep as when these materials are included. Other ingredients known per se, for example conditioning agents, perfumes,

  antistatic and other agents may be included in the compositions

  or can be applied later to the hair.

  The following examples will serve to better illustrate the present information.

vention.

EXAMPLE 1

  The following promoter composition is prepared: Cu 504.5 H 20 1% 940 carbomer 0.5% sodium lauryl sulfate 1% monoethanolamine at p H 9.5 water qs per 100 The following dye composition is prepared: sodium acetate 1.2% 5,6-dihydroxyindole 1.2% carbomer 940; 0.47% ethanol 19.7% sodium hydroxide at p H 8.5 The hair is saturated with the catalytic composition for 5 minutes and then rinsed with water Then the hair is saturated with the composition containing 5.6 -dihydroxyindole for a period of 5 minutes With the hair dyed black which results therefrom,

  shampoo to remove all melanin from the surface of the hair.

EXAMPLE 2

  Light brown hair is dyed black according to the operating mode.

  roof of Example 1 Then, the hair is saturated with a 6% aqueous solution of hydrogen peroxide at p H 9 Ten minutes later, when the original light brown shade of the hair is reached, the hair is

  rinsed The same operation is repeated, but-the hair is lightened during the

  for 6 minutes until a dark brown shade Three weeks later, the hair is still lightened for 3 and a half minutes until their

original light brown shade.

EXAMPLE 3

* The same procedure is repeated as in Example 1 on straight hair, except that the concentration of 5,6-dihydroxyindole is only 0.5%. The dyeing is carried out for only 2 minutes until a light to medium gray color After shampooing, use a 6% aqueous hydrogen peroxide solution at p H 9 to lighten

  hair up to a light brown shade within 6 minutes.

EXAMPLE 4

  The copper sulfate solution of Example 1 is replaced using 0.25% Fe SO 4 based on the composition premixed with citric acid in a suitable amount to prevent precipitation

-253693

  iron at alkaline p H and monoethanolamine is used to adjust

p H at 9.5.

  The procedure of Example 1 is repeated, except that the solution

  containing 5,6-dihydroxyindole does not contain 940 carbomer.

  The hair is exposed to the catalyst solution for 10 min.

  nutes, then they are rinsed and saturated with the solution containing 5,6-

  dihydroxyindole for 10 minutes until the hair initially

  colored in light brown become distinctly darker.

EXAMPLE 5

  The same procedure is repeated as in Example 1, except that the solution containing 5,6-dihydroxyindole is applied first.

  and that it is followed, after rinsing, by the solution containing the catalytic

  lyser The resulting color on the hair is less intense than

in the case of Example 1.

Claims (20)

REVENDI CATIONS   1. Hair dyeing process, characterized by the following steps:   according to which the hair to be dyed is brought into contact with a solution of a metal which promotes the formation of imelanin from 5,6 dihydroxyindole before or after the step mentioned above, the hair is brought into contact with a solution of 5,6-dihydroxyindole, the hair is rinsed between the two stages of contacting, the contact with the second solution is maintained until a desired darker color is obtained,   we rinse the hair or shampoo it, then put the hair on   want to be in contact with a hydrogen peroxide solution for a period   maximum of 15 minutes until the desired shade of color is obtained   held and then rinse the hair again.   2. Hair dyeing process, characterized by the following steps   that the hair is dyed-in contact with an alkaline solution   holding a cupric ion, before or after the step mentioned above, we put the che-   want in contact with a solution of 5,6-dihydroxyindole, we rinse the che-   want between the two contact stages, we maintain contact with the second solution used until a darker color desired   sit down, and rinse the hair or shampoo it.   3 hair dyeing method according to claim 1, charac-   terized in that at least one of the metals is chosen from the group consisting of iron, cobalt, manganese, copper, silver, titanium, zirconium, tantalum, chromium, nickel, palladium, platinum, gold, mercury, cadmium, zinc, tin, antimony, lead and bismuth.   4 hair dyeing method according to claim 1,   characterized in that the p H of the metal-containing solution is at least 8.   5. Hair dyeing method according to claim 1,   characterized in that the p H of the solution containing 5,6-dihydroxy- indole is at least 8.   6 hair dyeing method according to claim 3, characterized in that the p H of the solution containing the metal is at least   minus 8 and in that the p H of the solution containing 5,6-dihydroxy- indole is at least 8.   7. A method of dyeing hair according to claim 2, characterized in that the p H of the solution containing the metal is at least   minus 8 and in that the p H of the solution containing 5,6-dihydroxy- indole is at least 8.   8. Hair dyeing method according to claim 2,   characterized in that in addition the hair is brought into contact with a so-   lution of hydrogen peroxide until the desired color is obtained. 9. Hair dyeing method according to claim 8, characterized in that the p H of the solution containing the cupric ion is at least 9.   10. A method of dyeing hair according to claim 9,   characterized in that the p H of the solution containing the hydro- gene is at least 8.   11 hair dyeing method according to claim 10, characterized in that the solution containing 5,6-dihydroxyindole is at least 8.   12. A method of dyeing hair according to claim 2, further characterized in that at least one of the solutions containing 5, 6-dihydroxyindole and containing the cupric ion additionally contains at   minus one of the following: thickener, surfactant   active, anti-static additive and fragrance.   13. A method of dyeing hair according to claim 10,   characterized in that at least one of said solutions containing 5,6-   dihydroxyindole and containing the cupric ion additionally contains at least one of the following products: thickener, surfactant, anti-static additive and fragrance.   14. Hair dye kit, characterized in that it comprises   in a single presentation a plurality of containers: a first   content containing an alkaline p H solution of an effective amount of a   metal that promotes the formation of melanin, a second container   closing a solution with an effective amount of 5,6-dihydroxyindole at pH acid, a space being reserved for the vapor above the solution in this second container and containing a non-oxidizing gas, a third container containing a alkaline agent, said space reserved for steam in the second container being of sufficient volume to receive this third container or the contents of this container within this space reserved for steam and a fourth container containing a solution of hydrogen peroxide.   15 Hair dye kit, characterized in that it comprises   in a single presentation a plurality of containers: a first   content containing an alkaline p H solution of an effective amount of a metal promoting the formation of melanin, a second container containing 2,536993   an alkaline solution, a space being reserved for the vapor above the solution in this second container, a third container containing a solution of an effective amount of 5,6-dihydroxyindole at p H acid, said space of the vapor in said second container being of sufficient volume to receive this third container or the contents of this third container in said space reserved for steam, and a fourth   container containing a solution of hydrogen peroxide.   16. Hair dye kit, characterized in that it comprises   in a single presentation a plurality of containers: a first   content containing an alkaline p H solution containing an effective amount   copper cace, a second container containing a solution of forty   effective amount of 5,6-dihydroxyindole at p H acid, a space being reserved for the vapor above the solution in this second container and containing in this space a non-oxidizing gas, and a third container containing   an alkaline agent, said space reserved for steam in said second container.   content being of sufficient volume to receive this third container or the content of this third container-in said space reserved for steam.   17. Hair dye kit according to claim 16, charac-   characterized in that the kit also includes a fourth container containing   a solution of hydrogen peroxide.   18. Hair dye kit, characterized in that it comprises   in a single presentation a plurality of containers; a first con-   content containing an alkaline p H solution containing an effective amount   copper container, a second container containing an alkaline solution, a   space being reserved for the vapor above the solution in said se-   container, and a third container containing a solution of an effective amount of 5,6-dihydroxyindole at p H acid, this space reserved for steam in said second container being of sufficient volume to receive said third container or the contents of this third container   within said space reserved for steam.   19. Hair dye kit according to claim 9, charac-   This kit also includes a fourth container containing   nant a solution of hydrogen peroxide.   20 Melanin-based hair dye as a new composition of matter, characterized in that this dye is prepared by bringing the hair into contact with a solution of 5,6-dihydroxyindole and before or after said step mentioned above, we put the hair in   contact with a solution of cupric salt.