Combined indole-aldehyde compositions for dyeing natural fibers, particularly for coloring human hair, are taught wherein the combined indole-aldehyde composition is either preformed or reacted in site on the natural fiber under acidic conditions. A method employing said compositions is also taught.

FIELD OF THE INVENTION 
This invention relates to dyeing compositions particularly suitable for 
coloring human hair. The dyeing compositions employ a combined 
indole-aldehyde composition as the coloring agent, which is either 
preformed or reacted in situ on the hair. 
BACKGROUND OF THE INVENTION 
Coloring of hair with a permanent or long wearing dye generally involves 
the oxidative reaction of a phenylenediamine, typically in the presence of 
a hydroxybenzene derivative to produce the indo-dye. An aryldiamine is 
normally mixed with a solution consisting of an oxidizing agent, usually 
hydrogen peroxide, and another agent such as a resorcinol. This mixture is 
then applied to the hair for a period of time long enough to impart a 
color which is resistant to shampooing and being rubbed off. With such a 
permanent dyeing system the color is formed within the hair fiber and is 
therefore trapped and not able to diffuse out. Permanent hair coloring 
procedures are usually performed at an alkaline pH between pH 8.5 and 11, 
which can cause some damage to the hair. Such oxidative dyeing of hair is 
generally accompanied by the readily perceptible deterioration of tactile 
properties of hair manifesting themselves in a raspy feel and increased 
difficulty in combing. 
The alkaline conditions under which the treatment procedure must be carried 
out further damages the hair and effects the morphological changes in the 
cuticular surface of the hair fibers as described by Mahrle, et al., "The 
Use of SEM to Assess Damage to Hair" in Hair Research; edited by C. E. 
Orfauos, W. Montagna and G. Stittgen; (Springer-Verlag; New York, 1981). 
Although practically speaking most, if not all, permanent hair coloring 
procedures are performed with alkaline media, neutral to acidic permanent 
hair coloring processes have been taught. For example, Shesiedo (JP 
53130443) teaches that the combination of a trihydroxybenzene with a metal 
salt of Cu(II), Fe(II) or Mn(II) in contact with hair over 60 minutes at 
pH 7 will impart a dark color to the hair . Very gradual hair coloring at 
pH less than 6 is taught in JP 85039645 (Bristol-Myers) by using a 
trihydroxybenzene or a trihydroxytoluene and a phenylenediamine in 
combination with air as the oxidant. Brown shades are achieved after 
repeated applications of the mixture. 
It is nonetheless apparent from the prior art that alkaline solutions of 
oxidizing materials are required in order to permanently dye hair in a 
relatively short period of time to achieve colors other than black or 
brown. 
Typical of various prior art references related to the field of this 
invention are the following: 
U.S. Pat. No. 4,620,850 (Bachmann et al.) discloses a composition for dying 
hair comprising derivatives of indole. The composition further comprises 
compounds such as protocatechualdehyde. The dyeing takes place at pH 2 to 
4; 
U.S. Pat. No. 3,871,818 (Kinney et al.) which discloses a solution 
containing an alkyl dialdehyde compound in combination with at least one 
nitrogen containing compound for changing the color of keratinous 
materials, particularly human nails; 
U.S. Pat. No. 4,695,285 (Chung-Bong-Chan et al.) which discloses the use of 
azidoindole for dyeing hair. The composition may also comprise a color 
coupler for interacting with azidoindole; 
U.S. Pat. No. 4,453,941 (Jacobs) which discloses a hair dye composition 
comprising indole derivatives in admixture with certain compounds having a 
reactive nitrogen moiety; 
U.S. Pat. No. 4,391,603 (Rosenbaum et al.) which discloses the use of 
hydroxyl derivatives of benzaldehyde for coloring keratin fibers without 
an oxidizing agent. 
None of the foregoing references nor any other prior art teaching of which 
the applicant is aware discloses the use of the method and compositions 
disclosed in the present application. 
SUMMARY OF INVENTION 
The present invention is directed to dyeing compositions and a method of 
using same, particularly for dyeing hair and other natural fibers 
employing as the coloring agent a combined indole-aldehyde reaction 
product which is either preformed or reacted in situ on the hair. 
DESCRIPTION OF THE INVENTION 
It has been found that employing a combination of an indole with an 
aldehyde at unadjusted pH and applying this combination to the hair, will 
result in a permanent hair color. It has also been discovered that the 
described reaction proceeds quickly and that the dyed hair has no rub-off 
of the dye after shampooing. It has, therefore, been concluded that the 
color forming process is occurring within the fibers of the hair. 
In making the determination and observations upon which the present 
invention is based, it was determined that the reaction between 
4-N,N-dimethylamino-benzaldehyde and pyrrolic compounds provides a simple 
colorimetric assay for the latter materials. In order to carry out such an 
assay, the aldehyde is dissolved in 50% water-ethanol at pH 3, this 
solution is known as Ehrlich's reagent and has been used for the detection 
of pyrroles and indoles since 1901. It has further been found that upon 
extending the use to other aldehydes with a variety of indoles, the 
reaction is quite general. Rapid color formation occurs, with the specific 
combination of a particular aldehyde and indole determining the 
chromophoric material that is produced. The reaction of indoles with 
aldehydes, commonly termed the Ehrlich reaction, occurs under acidic 
conditions and is believed to involve an electrophilic attack by the 
pyrrole portion of the indole on the aldehyde carbonyl group. 
Based upon the teachings of the prior art, it is very surprising that no 
acid catalyst is required to initiate the color forming reaction between 
the indoles and aldehydes on hair. Indeed, it is unexpected that hair 
should be such an efficient accelerator of this reaction. 
Preferably the indole used in the present invention will have the structure 
##STR1## 
wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each selected 
from H, CH.sub.3, ethyl, propyl, isopropyl, alkoxy, aryl, and aryloxy; and 
wherein R.sub.2, R.sub.4 .R.sub.7 are each selected from H, OH, NO.sub.2, 
NH.sub.2, N(alkyl).sub.2, N(alkoxyl).sub.2, N(hydroxyalkoxy).sub.2, and 
aryl. 
The aldehyde used will preferably have the structure 
##STR2## 
wherein R.sub.8 is selected from H, CH.sub.3, alkyl, alkenyl, alkynyl, 
benzyl, aminobenzyl, dialkylaminobenzyl, dialkoxylaminobenzyl, cinnamyl, 
aminocinnamyl, dialkylaminocinnamyl, dialkoxylaminocinnamyl, nitrobenzyl, 
alkylbenzyl, alkoxybenzyl, phenol, dihydroxyphenyl, trihydroxyphenyl, 
nitrohydroxyphenyl, hydroxycinnamyl, and acetamidophenyl. 
Specific indole derivatives useful herein are exemplified by skatole, 
5,6-dihydroxyindole,4-,5-,6-, or 7-hydroxyindole, 5-aminoindole, 
N-methylindole, 5-, or 6-, or 5,-6-benzyloxindole, 
methylene-5,6-dioxyindole and the like. Mixtures of the foregoing may also 
be employed. 
The conditions under which the indole and aldehyde components are brought 
together, i.e. reacted, are generally well-known. It is generally 
preferred, however, that the contacting of these reagents take place at a 
pH of about 2 to about 10. 
While the invention has been described above, the details of the present 
invention will be best understood by recourse to the following examples:

EXAMPLES 
GENERAL COMMENTS 
In the following examples the indole compound is added to an aqueous 
ethanol solution(10 to 40% ethanol). Preferably the indole is completely 
dissolved in the aqueous ethanol solution. Alternatively, the indole may 
be added to a gel based medium such as is obtained by mixing, on a weight 
percent basis, with the following formulation; deionized water (58%), 
Cellosize QP 4400 (1.1), ammonium lauryl sulfate (6.0), citric acid (1.6), 
SD alcohol 40 (33.0) and Polysorbate 20 (0.2). Additionally a thickened 
dye base may be made by mixing water (85%), carbopol-40 (1.5%), ethanol 
(12%) and monoethanolamine (1.5%) to which the indole and aldehyde may be 
added together or separately. 
The indole mixture is then worked into the hair, followed by application of 
the aldehyde, which may also be in an aqueous ethanol solution of a gel 
base. Alternatively, the hair can be contacted with a combined mixture of 
the aldehyde and the indole for from about 5 to 30 minutes, shampooed and 
then dried. An intensely colored dye-out that proves to be long wearing 
and resistant to shampooing as well as to light exposure is obtained. 
Furthermore, the formed color is generally resistant to oxidation even 
under alkaline conditions. 
EXAMPLE 1 
Using the sequential application procedure outlined above, a sample of 
blended grey hair was dyed with 5-aminoindole and 
4-N,N-dimethylaminocinnamaldehyde. After contacting the hair with 3% 
H.sub.2 O.sub.2 at pH 9.5 for 15 minutes or exposing the swatch to 
artificial sunlight for 10 hours, the only change in the dye-out is a 
moderate loss of the red tones. 
EXAMPLES 2-34 
Using the same procedures as outlined in the general comments above and as 
used in Example 1, a number of samples of blended gray (BG) hair, and 
bleached (BL) hair were dyed in-vivo by the sequential reaction of an 
indole and an aldehyde separately. Total dye-out times of 15 minutes 
followed by shampooing were used. The amount of indole and aldehyde used 
was 1% of each on a wt/wt basis. Examples 2-34 are in Table 1 which shows 
the specific indole and aldehyde used and the results obtained. 
TABLE 1 
__________________________________________________________________________ 
EXAMPLES 2-34 
Ex- 
ample 
Indole* Aldehyde* 
Hair Type 
Dyeout and comments 
__________________________________________________________________________ 
2 DAI DACA BG Light yellow golden-brown. 
3 " " BL Yellow-orange. 
4 NCH.sub.3 DH 
2,4OBZ BG Dark grey w/yellow tones. 
5 " " BL Mousy light brown. 
6 NCH.sub.3 DHI 
DACA BG Light brown w/yellow tones. 
7 " " BG pH 9 H.sub.2 O.sub.2 bleachout of Ex. 6, = 
golden brown w/yellow. 
8 " " BL Dark yellow-brown. 
9 " " BL pH 9 H.sub.2 O.sub.2 bleach out of Ex. 8 = 
mousy brown. 
10 " DMAB BG Violet w/brown tones. 
11 " DMAB + BG Dark violet w/yellow tones. 
2,4OBZ 
12 5AI DMAB BG Dark yellow orange. 
13 " " BG pH 9 H.sub.2 O.sub.2 post-treatment of Ex. 
12 = 
medium golden brown. 
14 5AI 2,4OBZ BG Intense fluorescent yellow. 
15 " " BG pH 9 H.sub.2 O.sub.2 post-treatment of Ex. 
13 = 
darkening of Ex. 14. 
16 " " Brown Hair 
Gives yellow tones. 
17 " " BG 10 hrs. Fad-o-meter of Ex. 14 = 
slight darkening 
18 " DACA BG Intense brown w/red-violet. 
19 " " BG pH 9 H.sub.2 O.sub.2 post-treatment of Ex. 
18 = 
intense brown. 
20 " " BG 10 hrs. Fad-o-meter of Ex. 18 = 
lightens. 
21 " " BL Deep cherry red w/violet. 
22 " " BL pH 9 H.sub.2 O.sub.2 post-treatment of Ex. 
21 = 
deep cherry red. 
23 " " BL 10 hrs. Fadometer of Ex. 21 = 
loses violet tones. 
24 " DACA + BG Medium brown w/red orange 
2,4OBZ tones. 
25 " " BG 10 hrs. Fad-o-meter of Ex. 24 = 
loses some reds. (dark 
strawberry blonde). 
26 
+ " " BL Intense burnt orange w/red 
tones. 
27 " " BL 10 hrs. Fad-o-meter of Ex. 26 = 
loses some reds. 
28 5AI + NCH.sub.3 DHI 
2,4OBZ BG Dark grey w/some yellow 
tones. 
29 " " BG pH 10 Cu.sup.+2 post-treat of Ex. 28 = 
dark brown-yellow. 
30 " DMAB BG Dark golden brown w/orange 
tones. 
31 " " BG pH 10 Cu.sup.+2 post-treat of Ex. 30 = 
Dark grey w/brown-gold 
tones. 
32 5AI GL BG Medium ash brown. 
33 In DACA BG Golden brown w/red tones. 
34 In GL BG Dark grey-brown. 
__________________________________________________________________________ 
*Abbreviations; 
DAI = 5,6diacetoxyindole; 
DACA = 4N,N-dimethylaminocinnmaldehyde; 
MDI = 5,6Methylenedioxyindole; 
DMAB = 4n,n-dimethylaminobenzaldehyde; 
NCH.sub.3 DHI = 5,6dihydroxy-N-methylindole; 
2,4OBZ = 2,4dihydroxybenzaldehyde; 
5AI = 5aminoindole; 
GL = glyceraldehyde; 
In = indole. 
EXAMPLES 35-48 
A number of additional samples of blended grey (BG) hair and bleached (BL) 
hair were dyed by first mixing the aldehyde and indole together in an 
alcohol-water based dye medium such as obtained by dissolving the indole 
and the aldehyde in an alcohol such as ethanol (30% vol/vol), adding this 
to 68 ml of water along with Cabosil gel agent or xantham gum (2 gm) with 
rapid stirring to produce the gel dye medium. 
This mixture is then applied to the hair sample for 15 minutes, followed by 
shampooing, to yield a long lasting dye-out. The amount of indole and 
aldehyde used was 1% of each on a wt/wt basis. These examples are set 
forth in Table 2 which provides a listing of the specific indole and 
aldehyde used for each example and the results obtained for each. 
TABLE 2 
______________________________________ 
EXAMPLES 35-48 
Indole-aldehyde* 
Hair Type Color 
______________________________________ 
35 DAI + DACA BG Medium gray-violet 
36 " BL Violet 
37 MDI + DMAB BG Light brown-violet 
38 " BL Violet-brown 
39 NCH.sub.3 DHI + 2,4OB.sub.z 
BG Light brown-violet 
40 " BL Light violet 
41 NCH.sub.3 DHI + DACA 
BG Intense medium golden 
brown. 
42 " BL Intense medium orange 
brown. 
43 5AI + DACA BL Intense cherry red 
44 5AI + DMAB BG Medium golden orange- 
brown. 
45 In + DACA BG Light auburn 
46 5AI + GL BG Medium brown 
47 In + GL BG Light grey w/violet 
tones. 
48 In + Acct BG Pale blue-green 
______________________________________ 
*Abbreviations: 
DACA = 4N,N-dimethylaminocinnamaldehyde; 
DAI = 5,6diacetoxyindole; 
NCH.sub.3 DHI = 5,6dihydroxy-N-methylindole; 
MDI = methylenedioxyindole; 
2,4OB.sub.z = 2,4dihydroxybenzaldehyde; 
DMAB = 4N,N-dimethylaminobenzaldehyde; 
5AI = 5aminoindole; 
In = indole; 
GL glyceraldehyde; 
Acct = acetaldehyde. 
While the invention has been described with respect to various specific 
examples and embodiments, it is to be understood that the invention is not 
limited thereto, reference being had to the appended claims for a 
definition of the scope of the invention.