AQUEOUS COMPOSITIONS FOR DARKENING KERATINOUS MATERIALS

Abstract: Aqueous compositions for darkening keratinous material, particularly hair, comprise a mixture of a solution of a salt of thiosulphuric acid, preferably in an amount of 0.2-5.0% by weight as thiosulphate ion, preferably as the sodium thiosul­ phate or an amine such as triethanolamine thiosulphate; with a solution of a complex of bismuth with an amino-polyacetic acid such as nitrilotriacetic acid or ethylenediamine tetracetic acid, the bismuth preferably being present in an amount (measured as carbonate) of 0.1-5.0% by weight; in the presence of a water-soluble amine, preferably an a alkanolamine such as mo­ no-, di- or triethanolamine in an amount to maintain the pH in the range 8 to 11; and of a di- or poly-hydroxy humectant, pref­ erably glycerol or propylene glycol in an amount of 5-70% by weight.

Description: AQUEOUS CObiPOSITIONS FOR DARKENING KERATINOUS SATERIELS. Solutions of salts of bismuth have been used to darken human hair and other keratinous matter for many years. For example, British Patent Specification 1467874 provides a hair-dyeing composition comprising sulphur and the water-soluble reaction product of bismuth citrate and triethanolamine in an aqueous vehicle. However, the rate at which these solutions react with the hair to produce the dark colour is slow, and many such formulations are not stable and need to be freshly prepared before use. Sulphur and sodium thiosulphate have been recommended to hasten the darkening process, but the rate at which hair is darkened has nevertheless hitherto been unsatisfactory. Lead salts have also been used in hair darkening compositions; lout the same problems arise and in addition the known toxicity of lead is a disadvantage. It is an object of the present invention to provide aqueous compositions containing bismuth which are able to darkec keratincus rr.aterials such as wool and fur and, particularly, hair and which are at the same time stable. The present invention provides an aqueous composition for darkening keratinous material comprising a mixture of a solution of a salt of thiosulphuric acid, with a solution of a complex of bismuth with an aminopolyacetic acid, in the presence of a water-soluble amine, and of a di- or poly-hydroxy humectant, Preferably the aqueous composition comprises from 0.2 to 5.0% by weight of thiosulphate ion (S2 03=), from 0.1 to 5.0% by weight of bismuth (as carbonate), water-soluble amineto maintain the pH in the range 8-11 and from 5 to 70% by weight of the humectant. The amino-polyacetic acid used as a complexing agent for bismuth may suitably be nitrilotriacetic acid (NTA) or ethylenediamine tetracetic acid (EDTA), EDTA being preferred. The method of preparation of the complex is not critical. According to one method, 10 parts of bismuth carbonate or bismuth oxycarbonate or the equivalent quantity of bismuth oxide may be suspended in water with either 12.5 parts of EDTA or 13.6 parts of NTA, the suspension heated, and a water-soluble amine added slowly with stirring until virtually all the solid matter is',dissolved. The composition of the invention preferably contains 0.1 to 5% by weight, particularly 0.25 to 1.5% by weight of bismuth, expressed as carbonate. The amount of complexing agent (e.g. EDTA) used should preferably be no more than is necessary to form a water-soluble complex, since an excess appears to decrease the efficiency of the composition for darkening hair. While the nature of the water-soluble amine is not critical, we have found that alkanolamines are particularly effective. Among these may be used monoethanolamine, diethanolamine, triethanolamine and tri-isopropanolamine. One of these alkanolamines may be used to complete preparation of the water-soluble bismuth complex as described above. In addition, it is preferred to include a further amount of alkali, preferably a water-soluble amine in an amount from 1-10%, particularly 2-5%, of the composition. The amount of excess alkali used should preferably be such as to bring the final pH of the composition to a value in the range 8-11, preferably 8-10.5. Compositions of the invention preferably have a pH in the range 6-11, particularly 8-10.5. As a di-or poly-hydroxy humectant, propylene glycol is preferred, although glycerol or polyethylene glycol may be used. The nature and proportion of the humectant materially affects the speed of darkening achieved by the composition. Thus for example, glycerol may be used to produce brown colours rapidly up to a concentration of about 30%. Above that level it has an increasingly deleterious effect. Propylene glycol on the other hand is particularly effective in promoting colour production in the range 20 to 70%. The water-soluble complexes of bismuth described above have some colouring effect on hair by themselves, but this effect is very much enhanced by the presence of thiosulphate. Compositions of this invention accordingly contain thiosulphate ion in a proportion of 0.2-5%, preferably 1-3% by weight. The thiosulphate may be added as the salt of any inert non-toxic metal, for example as sodium thiosulphate. Ammonium thiosulphate may be used, but is liable to give rise to a smell of ammonia. A preferred alternative is .to use the thiosulphate o± an amine, such as the amine or alkanolamine described above in connection with the bismuth complex. Amine tblosulphates may readily be. prepared ty boiling an aqueous mixture of ammonium thiosulphate with an amine having a suitable vapour pressure and water solubllit; the resulting aqueous solution can be used without the need to isolate the compound. Solutions of mono-, diand triethanolamine thiosulphate are particularly convenient to prepare and use in this way. The amine used is additional to that used in forming the watersoluble complex of bismuth and the further proportion included in the composition as described above. It is possible to include sulphur in the aqueous composition, in addition to the thiosulphate, but this has the disadvantage of incorporating a water-insoluble i.gredient. Other conventional ingredients, such as monohydric alcohols, perfumes, thickening agents and surface 'ac;:ive agents, may be used in conventional amounts. The invention also includes a method of darkening keratinous material by applying to the leratinous material an aqueous composition as described above. The following examples illustrate the invention. Examples 1 to 5 describe the preparation of water-soluble complexes of bismuth. The remaining examples descX be compositions according to the invention. Example 1 Bismuth carbonate (5.0g) and ethylenediamine tetracetic acid (6.25g) are "suspended in 120 ml water and the mixture is heated with stirring at not less than 600C until effervescence ceases. TriethÅanolamine (about 5.Og) is then added slowly with continued stirring to produce a solution with a pH of about 8.0. The solution, which contains a small quantity (about 0.Olg) of insoluble residue, is cooled to room temperature and filtered from the insoluble residue. The filter is washed with a little water and the washings added to the main filtrate which is then diluted to 200ml with water. Example 2 A mixture of bismuth cabonate (lOg) and ethylenediamine tetracetic acid t12.5g) in water (6oil) is treated as in example 1, the final filtered solution being diluted to lOOml. 9.5g of triethanolamine was used in this preparation and the insoluble residue weighed 0.03g. Example 3 Proceed essentially as in Example 1 above, but ting 6.8g cf nitrilotriacetic acid in place of the ethylenediamine tetracetic acid. Example 4 Bismuth carbonate (5.0g) and ethylerediamine tetra tetracetic acid (6.25g) are suspended in 60ml water and the mixture is heated to about 60 C with stirring while monoethanolamine is added dropwise to about pH 6. Heating and stirring are continued until effervescence has vi-tually ceased -nd then monoethanolamine is again added until the pH has risen to about 9.7 when nearly all the solid matter will have dissolved. The mixture is then cooled to room temperature and filtered from the insoluble residue (about O.lg). The residue is washed as in Example 1 and the final solution is diluted to loom. About 3g of monoethanolamine was used in this preparation. Example 5 Proceed essentially as in Example 4 but using diethanolamine instead of monoethanolamine. The final pH is about 9.1. Example 6 To loll. of the solution prepared according to Example 1 there is added, with stirring, a mixture of nonyl phenol ethoxylate (9 mole) (hereafter referred to as NP9) t .Sg), triethanolamine (3g), glycerol (15g) and isopropyl alcohol (6ml). To this solution is then added a solution of sodium thiosulphate (3g) in water (20ml) and She whole is diluted to 100ml with water. This solution contains 1.37% as thiosulphate ion and has a pH of approximately 9.5. This composition darkens hair gradually with successive applications. Example 7 To a mixture of NP9 (0.5g), triethanolamine (3g) and isopropyl alcohol (6ml) and water (loml) add 2.5ml of the solution prepared as described in Example 2. To this mixture then add propylene glycol (60g) followed by a soluticn of sodium thiosulphate (5g) in water (15ml) Stir the solution a-;ld dilute to lOOml with water. This formula contains 2.26% as thiosulphate ion. This composition darkens hair significantly with one application. Example 8 To a solution of NP9 (O.5g), triethanolamine (3g), perfume (O.2g) and glycerol (20g) in ethyl alcohol (20ml) add, with stirring, lOml of the solution prepared as described in Example 1 followed by a solution of sodium thiosulphate (5g) in water (20ml). To the final mixture add a solution of hydroxyethylcellulose (O.g) in water (lomi) and dilute the whole to lOOml. Example 9 To a solution of NP9 (0.5), triethanolamine (8g), glycerol (20g) and isopropyl alcohol (6ml) in water (20ml) add, with stirring, l0ml of the solution prepared as described in Example 1 followed by a solution of sodium t.liosulphate (5g) in water (20m1). Dilute the resulting mixture with water to lOOml. Example 10 Following the procedure described in Example 9, use l0ml of the solution prepared as described in Example 3 in plece of that described in Example 1 and 3g triethanolamine rather than 8g. Also before final dilution with water to l00ml add 2g finely divided sulphur. Thts composition will darken hair at a faster rate than will a similar composition which does lot contain sulphur. Example 11 Follow the procedure described in Example 6, but use 3g diethanolamine instead of triethalsolamine. The approximate pH of the final solution is 11.0. Example 12 To a mixture of NP9 (0.5g), isopropyl alcohol (6ml), triethanolamine (9g) and propylene glycol (55g) add, with stirring, lomi of the solution prepared as describcd in Example 1 followed by ammonium thiosulphate (3g) and dilute the mixture to looms. This composition acts similarly to that of Example 7. Example 13 To a solution of ammonium thiosulphate (30g) in water (120ml) add triethanolamine (60g). Heat the mixture to boiling and continue to boil till the total weight is reduced to about 150g when most of the ammonia released will have been driven off. The pH of this mixture is about 8.5 To this solution, at room temperature, is then added, with stirring, a mixture comprising 50ml of the solution prepared as described in Example 2 a polvethanoxyl alkyl ether containing a nominal eight molecules of ethylene oxide (hereafter referred to as KA8 (5g), triethanolamine (30g), propylene glycol (400g) and isopropyl alcohol (60my). The whole is then diluted to 1 litre with water. The solution contains 2.3% as thiosulphate in. This composition acts similarly to that of Example 7. Example 14 Heat a solution of ammonium thiosulphate (30g) and triethanolamine (60g) in water (120ml) as described in Example 13 and dilute the final concentrated mixture to 150ml. Add an aliquot (15ml) of thi: solution with attiring to a mature of NP9 (0.5g), isopropyl alcohol (6ml) and propylene glycol (55g) and to the resulting solution add lOml of the solution prepared as described in Example 1. Dilute the resulting mixture with water to lOOml. This composition will darken hair or wool by immersion to a marked degree. Example 15 To a mixture of KA8 (0.5g), triethanolamine (3g), propylene glycol (45g) and perfume (0.2g) Jj:j ethanol (12ml) add, with stirring, 10 ml of the solution prepared as described in Example 2 followed by 15ml of the solution prepared from ammonium thiosulphate and triethanolamine as described in Example 14. Example 15 Heat a mixture of ammonium thiosulphate (lOg) and diethanolamine (4.2g) in water (iOml) until the mixture has lost 5g in weight and dilute the resultant solution to 50ml with water. To l5ml of this solution add 3g triethanolarnine and proceed then as in Example 14. The final solution contains 2.3% as thiosulphate ion. This composition performs similarly to that of Example 7. Example 17 Concentrate a mixture of ammonium thiosulphate (lOg) and monoethanalamine (8.24g) in water (20ml by boiling to a final weight of about 21g. Dilute the concentrate to 50ml with pater and use 15ml of this solution as described in Example 16. The final mixture contains 2.3% as thiosulphate ion. This compositicn performs similarly to that of Example 7. Example 18 Proceed as in Example 14, but use l0ml of the solution prepared as in Example 3 instead of as in Example 1, and include also 3g triethanolamine. This composition performs similarly to that of Example 7. Example 19 To a mixture of KA8 (0.;o), diethanolamine (3g), propylene glycol (50g) and isopropyl alcohol (6ml) add 5ml of the solution prepared as in Example 2. Stir and then add 15ml of the solution prepared from ammonium thiesuiphate and triethanolamine as described in Example 14. This mixture has a pH of about 9.5. It gives very good darkening of the hair with one application. Example 20 Proceed as in Example 19 but use monoethanolamine (3g) in place of diethanolamine. The mixture has a pH of about 10.4 and has a similar action on hair to that of Example 19. Example 21 To a mixture of K!L8 (0.5g), diethanolamine (3g), propylene glycol (50g) and isopropyl alcohol (6ml) add lOml o; the solution preapared as in Example 5. Stir and then add lxml of the solution prepared from ammonium thiosulphate and diethanolamine as described in Example 16. This has pH 9.6 and gives particularly good darkening of the hair with one application. Example 22 To a mixture of KA8 (0.5g), monoethanolamine (3g), propylene glycol (50g) and isopropyl alcohol (6ml) add lOml of the solution prepared as in Example 4. Stir and then dd 15 ml of the solution prepared from ammonium thiosulphate and monoethanolamine as described in Example 17. Vnis has pH 10.5 and gives very good darkening of the hair with one application. Tests on white wool, grey hair tresses and human volunteers have shown that these compositions will darken; hair or wool much more rapidly than formulations heretofore described. Samplcs kept for six months in glass containers at 40 C have shown no sign of deterioration and chemical analysis has indicated no change in the thiosulphate.

Claims: CLAIMS 1. Aqueous composition for darkening keratinous material comprising a mixture o' a solution of a salt of thiosulphuric acid, with a solution of a complex of bismuth with an amino-polyacetic acid, in the presence of a water-soluble amine, and of a di-or poly-hydroxy humectant. 2. Aqueous composition as claimed in claim 1, comprisil1g from 0.2-5.o by weight of thiosulphate ion (5203=), from 0.1 to 5.0% by weight of bismuth (as carbonate), a water-soluble ntmire to maintain the pH of the composition in range 8-11, and from 5-70% by weight of the humectant. 3. Aqueous composition as claimed in claim 1 or claim 2, wherein the amine is an alkanolamine. 4. Aqueous composition as claimed in claims 3, wherein the alkanolamine is monoethanolamine, diethanolamine or triethanolamine. 5. Aqueous comMosition is claImed in any one of claims 1 to 4, wherein the amino-polyacetic acid is ftrilotriacetic acid or ethylenediamine tetracetic acid. 6. Aqueous composition as claimed in any one of claims I to S, wherein the solution of a salt of thiosulphuric acid is provided by a solution of an amine thiosulphate. 7. Aqueous composition as claimed in any one of claims 1 to 5, wherein the solution of a salt of thlosulphuric acid is provided by a solution of sodium, potassium or ammonium thiosulphate. 8. Aqueous composition as claimed in an one of claims l to 7, wherein the humectant is propylene glycol. 9. Aqueous composition as claimed in claim 8, wherein the propylene glycol is present in an amount of 20-70X by weigiit. 10. Aqueous composition as claimed in any one of the claims 1 to 7 wherein the huectant is glycerol. 11. Aqueous composition as claimed in claim 10 wherein the glycerol is present in an amount of 5 to t0 ? by weight. 12. aqueous composition is claimed in any one of claims 1 to 11, comprising thiosulphate ion in an amount of 1-3% by weight, bismuth (as carbonate) in an amount of 0.1-1.5 by weight, the bismuth being present in the form of a complex with ethylenediamine tetracetic acid in the presence of monoethanolamine, diethanolamine or triethanolamine in an amount to maintain the pH of Fhe composition in the range 8 to 10.5, and propylre glycol in an amount of 35-55 ' by weight. 13. A method of darkening keratinous material which method comprises allying to the keratinous material the aaqueous composition claimed in any one of claims 1 to 12.

Inventors: HOLLAND, DAVID O.
Applicants: COMBE INCORPORATED
Application year: 1981
Main classification: A61K7
IPC codes: A61K8, A61Q5, D06P3