FR2491080A2 - Dyeing keratin substances, e.g. skin, nails, hair, fur - with compsns. contg. ketone or aldehyde dye and sulphoxy-aminoacid - Google Patents

Abstract

In dyeing keratin-contg. substances or tissues with a dyestuff or co-reagent having a ketone- or aldehyde function, colour formation is intensified by also applying a sulphoxy gp.-contg. aminoacid, (I), before, during or after treatment with the dye or co-reagent. The materials can be used (1) in cosmetics, for skin-tanning and for dyeing nails and hair, (2) for dyeing furs and feathers and (3) for colouring horn, scale or tortoise-shell articles. A uniform shade is obtd. The colour resists washing and is developed more quickly. (I) are more soluble in water than thioaminoacids, whereby more solns. can be used. The sulphoxide function allows penetration and fixation of (I), and derived dye complex, in horn layer. (I)-derived compsns. are odourless.

Description

 The present invention provides an improvement to the process and to the composition for the coloring of substances or tissues containing keratin, and in particular for the tanning of the skin.

 In the main patent, a method has been described which consists in applying to keratin materials, simultaneously or successively, a solution of coloring agent comprising aldehyde and / and ketone functions, and an amino acid solution. The latter is preferably a sulfoxide derived from an amino acid, the molecule of which carries one or more sulfur atoms. The composition, according to the main patent, consists of a set of two separate solutions or dispersions, one of which contains the coloring agent and the other one or more amino acids.

 The improvement according to the present First Addition allows a much better conservation of the compositions intended for coloring; it avoids the alteration of coloring agents and the release of an odor by amino acids, it also results in faster and more intense coloring of the keratin substances treated with these compositions.

 The invention results from the observation that both the aldehyde or ketone coloring agents and the amino acids are best preserved in a weakly acid medium, while the preferred pH for their reaction is at least 7.

 The new process therefore consists in preserving the reagents in the form of solutions with a pH below 6.5 and preferably below 5, but mixing them with a basic substance, at the time of use, so that they are at this time there in a pH greater than 6.5, in particular between 6.5 to 8.5, preferably between 7 and 8.

 Amino acids can be stored in the middle of pH 5, while for coloring agents it is preferable not to exceed pH 4.

 When the pH, during storage, is sufficiently low, the two kinds of reagents, that is to say aldehyde or / and ketone coloring agents and amino acids can coexist in the same solution, without reacting. Thus, at pHs not exceeding 4, it is possible to keep a solution containing both the coloring agent and the amino acid, without this solution coloring; it suffices to mix it with a basic solution, just before its application to the material to be treated, such as skin, hair, fur, etc., or else on this same material, to obtain the desired coloration.

 This results in an advantageous embodiment of the invention: a solution of the coloring agent, containing amino acid, is preserved after adjusting its pH to a value not exceeding 4, preferably of 2 to 4, or better from 3 to 3.9, but the pH of this solution is brought to 6.5-8.5, preferably 7 to 8, at the time of use. The preferred composition, according to the invention, is thus constituted by two separate solutions, one containing the coloring agent or co-reactant and the amino acid, with a pH not exceeding 4, the second being a basic solution of concentration and quantity such that mixing it with the first leads to a pH of at least 7, or better still from 7 to 8.

A preferred embodiment of the invention consists in using two solutions kept separately t
I - mixture of co-reactant and sulfoxy-amino acid in water at a pH not exceeding 4, and II - a basic solution to be mixed with solution I, at the time of use, the resulting solution must have a pH of at least 7, preferably 6.5 to 8.5.

 An improved process and composition are thus produced, unexpected with respect to the known technique.

Indeed, according to the prior art, in particular French patent No. 1,252,400, coloring agents, such as glyceraldehyde, dihydroxy-acetone or glycoLAdéhyde, could be used with compounds containing nitrogen, for example amino acids, provided that the pH of the solution is from 4 to 6. However, with these pH the reaction being slow, one cannot obtain a fast coloring; but neither can the solution be kept, since the reaction takes place in a certain number of hours.

 On the other hand, US Patent No. 2,948,657 recommends the use of compositions containing certain diketones and lower amino acids, in an aqueous medium of pH 7.5 to 8.5, for coloring the skin. In reality such solutions must be reused as soon as they are prepared, since their conservation is difficult, especially when the diketones are linear. By its mode of conservation at pH less than 6.5, and preferably below 4, the present invention provides significant technical progress on the process of this American patent.

 The aldehyde or / and ketone coloring agents, and the amino acids, as well as their proportions which can be used according to the invention have been defined in the description of the main patent, there is therefore no longer any need to describe them here; it will only be noted that the invention can be applied, in general, to the various coloring agents and adjuvants of the prior art.

 As regards the basic solution, which constitutes the second solution of the composition according to the invention, it can be aqueous, alcoholic, hydroalcoholic or contain another solvent miscible with water; the base or bases which it contains are mineral or organic, for example sodium hydroxide, potassium hydroxide, carbonate and / or bicarbonate of Na or K, phosphate, borate, acetate, citrate, etc. of alkali metal, ammonia, diethanolamine, triethanolamine or others.

 The base concentration of this second solution is not critical, but it is practical that it is of the order of 0.1 to 2 moles per liter. Its quantity is calculated so that its mixture with the active acid solution leads to a resulting pH of 6.5 to 8.5.

 The invention is illustrated without limitation by the following examples.

EXAMPLE 1
An aqueous solution I is prepared at 0.72 mole of dze methionine per liter, at a pH adjusted to 3.5 by addition of hydrochloric acid; in this solution is dissolved, per liter, 1.6 mole of dihydroxyacetone (DHA).

On the other hand, a solution II of 0.5 mole of monopotassium phosphate is prepared with 0.41 mole of NaOH, per liter. Solution I remains stable as long as it is not neutralized. At the time of use, the solutions I and II are mixed, so as to obtain a mixture at pH 7.45; this mixture contains 2.22 moles of ketone per mole of amino acid. The mixture is maintained at 320C and the development of its color is followed by the measurement of the optical density after times ranging between 24 and 96 hours.

As the colored complex has no maximum in the visible range, the measurements are carried out in the very near ultraviolet lt, at 420 nm, on the above-mentioned mixture, diluted to 1/10.

The table below gives the optical densities found for the various mixtures; these are the means of 3 or 4 measurements. In the vertical column of the results after 3 h, the optical densities measured are plotted on the undiluted mixture, while the other columns relate to liquids diluted to 1 / loto M denotes the mixture in which the amino acid is of the methionine.

S corresponds to the mixture of which the amino acid is methionine sulfoxide.

AA designates the mixture of the 16 amino acids present in the connective layer of the dermis, that is to say a set of amino acids, in which serine and citrulline predominate (composition determined by Spier and Pascher).

Pure Diluted 1/10
3h 24h 48h 72h 96h
M 0.035 0.14 0.24 0.34 0.30
S 0.067 0.21 0.39 0.47 0.48
AA 0.065 0.16 0.27 0.37 0.37
We see that the methionine sulfoxide (line S) added to dihydroxy-acetone changes the color of the mixture more quickly than do the natural amino acids (AA), and it leads to a much higher final intensity: optical density 0.47 after 72 h instead of 0.37.

EXAMPLE 2
Application tests on the skin of voluntary subjects were carried out with the following two creams, the compositions of which are indicated by weight.

Cream t
Mo nodipalmito polyoxyethylene gly stearate
collar ("Tefose 1500") ......................... 6
Stearic acid .............................. 1
(Cetyl alcohol ............................. 2
Polyoxyethylene oleic glycerides ......... 5 (Isopropyl myristate ...................... .. 5
19
(Preservative: ester of parahydro acid
(xybenzotque .............................. 0.15
II t Methionine sulfoxide ................... 4.3
Water ....................................... 6
HCl in sufficient quantity for pH: 3.5 69.95
The aqueous solution II is introduced into the fatty dispersion I with moderate stirring, after both have been brought to 700C. 1.5 parts of dihydroxy-acetone (DHA) are then added to the finished and cooled cream.

Cream 2
I Stearic acid ... 19 + Water .... 55
II (Potash tablets 2)
(Soda in pellets. 0.8 3 for pH = 9); Water .. 13
III Glycerin 10
In suspension I, maintained at 700 with moderate stirring, the basic solution II is gradually introduced, then the glycerin III. The whole, cooled to room temperature, has a pH of 9. By spreading over the skin an equivalent volume of each of these creams 1 and 2, a mixture is obtained whose pH is between 7 and 8. Thus , we proceed on the skin of 10 patient volunteers, at a rate of 7.5 mg per cm2. On control areas, only spread a cream 3 of pH 7 which contains coloring agent (DHA), without amino acid.

The results of these tests are the same as those of
Table, page 8 of the main patent, except that the times of appearance of the coloration on the zones II, that is to say where the creams 1 and 2 were applied, are 10 to 15 minutes shorter. Zones I were coated only with cream 3, free of amino acid.

EXAMPLE 3
Cream 2 of Example 2 is replaced by the following cream:
I Stearic acid 20 + Triethanolamine 0.5 + Water 41
(Potash in tablets 0.77 + Soda in tablets 0.27 II (. Water 21
+ Water 21
(Sorbitol 6 + Glycerin 3.5 + Water (Sufficient quantity
III (health 100)
Phases I, II and III are mixed in the same order and under the same conditions as for the preparation of the cream of Example 2. The mixture of these two creams spread on the skin, in substantially equal volumes, pre- feels a pH between 7 and 8.

The results are similar to those of Example 2.

Claims (5)

CLAIMS 1, Process for coloring a substance or a tissue containing keratin using a coloring agent with aldehyde or ketone function, in the presence of an amino acid, in a medium of pH greater than 6.5 , charac terized in that the coloring agent and the amino acid have been stored in solution or dispersion at a pH of less than 6.5, preferably less than 5 or, better, not more than 4, and that their pH is brought to a value greater than 6.5, preferably between 6.5 and 8.5, only at the time of use.  2. Method according to claim 1, in which the coloring agent is stored in the form of an aqueous solution whose pH does not exceed 4.  3. Method according to claim 1 or 2, characterized in that the amino acid is stored in the form of an aqueous solution at pH less than 5.  4. Method according to claim 1, characterized in that the coloring agent and the amino acid are stored in the same aqueous solution of pH 2 to 4, in particular from 3 to 3.9.  5. Method according to one of claims 1 to 4, characterized in that the raising of the pH above 6.5, at the time of use, is carried out by means of a basic solution mixed with the solution of l coloring agent and that of the amino acid just before the treatment of the keratinous substance or on this same substance.  6o Composition for coloring a substance or a tissue containing keratin, which comprises an aqueous solution of coloring agent with aldehyde or ketone function and an amino acid, characterized in that it is formed by two solutions separated: I- the first, of pH less than 6.5, containing the coloring agent and the amino acid, II- the second being a basic solution, in such quantity and of pH such that its mixture with the first leads at a pH greater than 6.5, preferably from 7 to 8.  7. Composition according to Claim 6, in which solution I contains an aliphatic diketone and an amino acid sulfoxy, characterized in that this solution has a pH not exceeding 4, preferably from 2 to 4, while solution II contains a base alkaline, an alkaline basic salt, ammonium or an organic base, preferably in an amount of 0.1 to 2 moles per liter.