Note: Descriptions are shown in the official language in which they were submitted.
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l067
05~9H CP-0
~AIR ~YEING PROCESS AND COMPOSITlONS PACKAGE
Field of the Invention
The present invention r01ates to a process for dyeing hair,
particularly hunlan hair, and composition package for carrying out that
process.
Background of the Invention
The color of human hair is due to the presence within its
structure of discrete natural pigment particles - the melanins. The
study of melanins and melanogenesis has intensified in the last 40
years, accompanied by some interest in the dyeing of hair with such
materials that most closely resemble the natural materials which
contribute the color to hair. The biosynthesis ~f melanin involves
conversion of tyrosine via dihydroxyphenylalanine (dopa) to melanin
through a number of intermediate steps , including 5,6-dihydroxy-
indole, to melanin.
In addition to the general desirability of dyeing hair in a
simple fashion and with a dye which is the closest to the material
that contributes the natural coloration of hair, a requirement also
exists for a hair colorant which can also serve, if desired, as a
temporary hair color which can be applied and removed at will and
which can be applied in a reliable and fast manner.
Summary of the Prior Art
Patents issuled which cover aspects of hair coloring with melanin
precursors, e.g. tyrosine, L-dopa~ L-dopa esters, and 5,6-dihydroxy-
indole. U.S. patents Nos. 2,539,202; 2,875,769; and 3,698,852 deal
with using L-dopa as the starting material. U.S~ patents Nos.
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2,934,396; 3,194,734; and 3,993,436 disclose the use of 5,6-dihydroxy-
indole as the starting material. The major disadvantages o~ these
systems are the time required for color development, the uncertainty
of the development and the lack of control over it, and the necessity
of adding compounds such as p-phenylenediamine and various couplers
for shade adjustment.
In the process disclosed in U.S. patent No. 2,934,396 hair is
first treated with an acidic or neutral solution o~ 5,6-dihydroxy-
indole, then the èxcess solution is blotted off and an o~idizing agent
or an oxidation-inducing solution is applied to the hair until the
desired shade is developed. In one o~ the methods disclosed in the
patent the oxygen of the ambient air is utilized wherein the second
solution contains an alkalizer and a cobalt or manganese oxidation
promoter. ~ainly, however9 an ammoniacal solution of an oxidizing
agent, such as of hydrogen peroxide or an alkali metal or ammonium
iodate, periodate or persulfate, etc. is taught to be emplcyed~ When
the desired shade is developed, the hair is rinsed, shampooed, rinsed
again and dried.
U.S. patent No. 3,194,734 is characterized as an improvement over
the above-mentioned U.S. patent No. 2,934,396, because in the process
o~ the earlier patent the dyeing which is the oxidative polymerization
of the 5,6-dihydroxyindole into melanin simultaneously competes with
an oxidative destruction of the dye that is being formed~ resulting in
a waste o~ indole, producing uneven results on the hair and it is
difficult to determine when to stop the process by rinsing. There-
fore, this later patent proposes a process wherein an aqueous alkaline
composition containing 5,6-dihydroxyindole and ammonia or an amine are
used to contact the hair until the desired shade is obtained.
Alternatively, certain methyl derivatives of 596~dihydroxyindole can
be employed in a two step process to obtain lighter shades wherein the
hair is first impregnated with an aqueous solution o such a methyl
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derivative in an acidic or neutral p~ solution9 then is briefly dried
and then the color is developed in a second step by application of an
aqueous solution con~aining an oxidizing agent.
Detailed Description of the Invention
The present invention is, in part, based on the discovery that,
in contrast to the prior art where H202 or other oxidants are used
either in a separa~e step, or together with the 5,6-dihydroxyindole,
to obtain a varie1:y of shades, superior results ~an be obtained by
utilizing a metal salt for promoting melanogenesis.
We discovered that a better variety of shades and more reliable
shade development and, if desired, improved temporary hair coloring
can be achieved by a hair dyeing process which comprises the steps of
contacting the hair to be dyed with a solution, suitably aqueous
solution, of a metal salt which promotes melanin formation from 5,6-
dihydroxyindole, then contacting the hair with a
solution, suitably a~ueous solution, of 5,6-dihydroxy-
indole, rinsing the hair between the two contacting stepsS maintainin~
the contact with the second-used solution until a desired darker color
is obtained~ rinsing or shampooing the hair, then contacting the hair
with a solution of hydrogen peroxide for a maximum of 15 minutes until
the desired color shade is obtained, and then again rinsing the hair.
In a particularly suitable embodiment of the process of the
present invention the process comprises the steps of contacting the
hair to be dyed with an alkaline solution, suitably an aqueous
solution, containing cupric ions, then contacting
the hair with a solution, suitably aqueous solution,
of 5,6-dihydroxyindole, rinsing the hair between the two contacting
steps~ maintaining the contact with the second-used solution until a
desired darker color is obtained, and rinsing or shampooing the hair.
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If a color other than grey or black is desired, the shade is obtained
with a subsequent treatment with H~02. Thus, it can be seen that
a pri~cipal distinction of the present process over all prior
proposals for dyeing with 5,6-dihydroxyindole is that in all cases,
except when the desired ultimate co]or is black, the hair is first
dyed to a grey or black color, and the ultimate desired shade is
subsequently developed by lightening with the hydrogen peroxide
solution.
A further feature of the present invention is a hair dyeing kit
which includes in a single package a plurality of containers,
comprising a first container including therein an aqueous alkaline p~
solution o an effective amount of a metal which promotes melanin
formation from 5,6-dihydroxyindole, a second container including
therein a solution of 5,6-dihydroxyindole at an acidic p~, a vapor
space being maintained above the solution in said second container and
containing a non-oxidizing gas in said space, a third container
including therein an alkalizer~ said vapor space in said second
container being of sufficient volume to accept said third container or
the contents of said third container with said vapor space, and a
fourth container which contains a solution of hydrogen peroxide.
In a further feature the present invention provides a hair dyeing
kit which includes in a single package a plurality of containers,
comprising a first container including therein an aqueous alkaline pH
solution of an effective amount of a metal which promotes melanin
formation from 5,6-dihydroxyindole, a second container incl~ding
therein an alkaline solution, a vapor space being maintained above the
solution in said second container, a third container including therein
a solution of an effective amount of 5,6-dihydroxyindole at acidic p~l,
said vapor space in said second container being of sufficient volume
to accept said third container or the contents of said third container
within said vapor space, and a Eourth container which contains a
solu~ion of hydrogen peroxide.
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, ,,
In yet another embodiment of the invention a hair dyeing kit is
provided which includes in a single package a plurality of containers,
comprising a first container including therein an alkaline pH solution
containing an effective amount of copper, a second container includin~
therein a solution of an effective amount of 5,6-dihydroxyindole at an
acidic pH, a vapor space being maintained above the solution in said
second container and containing a non-oxidizing gas in said space, and
a third container including therein an alkalizer, said vapor space in
said second container being of sufficient volume to accept said third
container or the contents of said third container within said vapor
space.
A further embodiment of the invention is a hair dyeing kit which
includes in a single package a plurality of containers, comprising a
first container including therein an alkaline pH solution containing
an effective amount of copper, a second container including therein an
al~aline solution9 a vapor space being maintained above the solution
in said second container, and a third container including therein a
solution of a~ effective amount of 5,6-dihydroxyindole at acidic pH,
said vapor space in said second container being of sufficient volume
to accept said third container or the contents of said third container
within said vapor space.
In accordance with the present invention, unless a black or grey
shade is desired, the hair dyed with the melanin from 5,6-dihydroxy-
indole is lightened with a hydrogen peroxide-containing solution. As
used throughout the specification and the claims, the term "hydrogen
peroxide" intends to denote hydrogen peroxide or any other ingredient
which is an aqueous solution forms hydrogen peroxide, such as urea
peroxide. This lightening or color shade-establishing step is
different from the conventional oxidizing treatment employed in the
conventional bleaching of hair. In conventional bleaching the natural
color of hair is removed by bleaching when it is desired to color it
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to a shade that is lighter than the natural color of the hair. In
that case the natural color of the hair is bleached out over a longer
period of time with a strong oxidizing solution which usually contains
hydrogen peroxide and additional bleach boosting persalts, around pH
10. This bleaching step generally tends to weaken or otherwise damage
the hair. In the lightening step of the present invention we do not
deal with the conventional kind of bleaching, because the hydrogen
peroxide solution used in the present invention does not contain added
bleach boosters such as persalts, it is suitably employed at a pH
below 10, suitably around 9~ and the lightening requires only up to
about 15 minutes for the lightest shades. Hence the lightening,
color-developing oxidizing step of the present invention is consider-
ably faster than conventional bleaching and is not employed to carry
the lightening further than the natural color of the hair or the co~or
that it had before the process of this invention was employed.
Without intending to be bound by the following explanation, we
believe that the difference in the lightening in accordance with the
present invention and conventional bleaching is attributable to ~he
new dyeing step of the present invention. In naturally colored hair
the melanin pigment is distributed throughout the cortex, i.e. the
inner core of the hair shaft. This means that in bleaching the
natural melanin color in hair with a strong bleach, such as hydrogen
peroxide as boosted by added persalts, considerable time is required
for the bleach to penetrate through the unpigmented periphery or
cuticle into the hair shaft. In the process of the present invention
the dye is believed to be disposed principally along the periphery of
the hair shaft and the lightening hydrogen peroxide does not require
the presence of percompound boosters and prolonged exposure to reach
and to bleach the dye. Due to the shorter exposure and the peripheral
penetration, the lightening step of the present invention does not
tend to damage or weaken the hair as is ~he case in conventional
bleaching.
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Furthermore, it is believed that the dyes produced in accordance
with the present invention are unique in that the melanogenesis-
promoting metal forms a complex with the melanin formed during
dyeing. The affinity of the complexed metal is viewed as being
greater for melanin than for the keratin of the hair. Therefore the
reactivity of the melanin-metal complex dye is greater with hydrogen
peroxide than that of melanin without the metal. This is borne out by
the observation that the melanin/copper complex produced in accordance
with the present invention can be lightened faster with hydrogen
peroxide than a natural melanin, even if a copper salt is dissolved in
the hydrogen peroxide used to lighten the natural melanin. Therefore,
the metal not only promotes melanin formation in the dyeing step of
the present invention, but is believed to contribute to the ease and
rapidity of the lightening step. For this reason we distinguish the
lightening step of the present invention which can be completed in
under 15 minutes from conventional bleaching which i~ of a different
kind and requires generally a time period that is well over twice as
long and requires bleach boosters in addition to hydrogen peroxide.
Accordingly, another feature of the present invention is a
complex melanin hair dye as a new composition of matter, said dye
being prepared by contacting hair with a solution of 5,6-dihydroxy-
indole, and before or after the aforesaid step contacting the hair
with a solution of a cupri~ salt.
The process of the present invention can also be used for dyeing
hair which was previously dyed with conventional permanent or
semipermanent hair dyes. As long as the original dye is sta~le to the
lightening solution that is milder than conventional hair bleaches,
the dyeing and lightening steps of the present process do not destroy
the starting color of the hair within the times employed herein for
lightening, whether or not the starting color is natural color of tl
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hair. Accordingly, hair colored by the present process can be
re-lightened to that starting color, whether that re-lightening takes
place the next day or a considerable time later.
If the present process is intended to color hair to a shade which
is lighter than the natural shade of hair, or lighter than a shade to
which hair was dyed by conventional techniques, then the hair has to
be first bleached lighter, or even bleached completely, before
employing the process of the present invention. In that case the
lightening treatment of the present invention can be carried to any
shade that is darker than the initially bleached shade, and then the
hair can be lightened to any inte~mediate shade, or if desired, the
initially bleached shade can be restored.
If the desired shade is a lighter one, it is not necessary to dye
~he hair entirely black, but dyeing to a lighter or darker grey will
suffice. ~hen the dye is then lightened in a subsequent step, it will
initially lighten to a lighter or darker brown shade, depending on
whether it was dyed to a lighter or darker grey in the initial steps.
Of all the melanogenesis promoters that were tested, only Cu2+ was
found to promote melanin formation all the way to an intense ~lack
color. The other metal promoters that were tested appear to assist
dyeing only to lighter or darker shades of grey. In our experiments
longer exposure of the hair or larger concentrations of the metal
promoter did not result in an increase of the resulting depth of color.
In the dyeing step the treatment of the hair with the solution o~
the melanogenesis ;promoter can generally precede or follow the
treatment of the hair with the 5,6-dihydroxyindole-containing
solution. Generally a better depth of color could be obtained when
the treatment with the promoter solution preceded ~he contacting with
the 5,6-dihydroxyindole solution. Any metal or transition metal ion
which is capable of promoting melanogenesis is believed to be suitable
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.
for that purpose. These include, for example, solutions of iron,
cobalt, manganese, copper, silver, titanium, zirconium, tantalum,
chromium, nickel, palladium, platinum, gold, mercury, cadmium, zinc,
tin, antimony, lead, bismuth, etc. The metal salts can be employed
alone or in mixtures. Except for cupric solutions it was found that
it is generally necessary to employ a chelatlng agent such as citric
acid, a citrate, ethylenediamine tetraacetic acid, ascorbic acid and
the like to keep the metal in solution.
Terms, such as "melanogenesis promoter", "melanogenesis-promoting
metal salt" and variants of such terms, as used throughout the
specification and the claims intend to refer to solutions of one or
more metals which will promote color formation in hair within a ~~
maximum period of 20 minutes after the hair was contacted with a
solution of 5,6-dihydroxyindole. Whether or not a given metal or a
given combination of metals can perform as a melanogenesis promoter,
can be determined by routine experimentation by trying out its ability
to ~orm a melanin dye in accordance with the process of the present
invention.
The melanogenesis promoter which was found most suitable is
Cu2+ which provides a considerably faster dyeing and the resulting
color can go all the way to solid black. While Fe~ ion will also
work well, it is less preferred than copper, due to solubility
problems at certain pH levels and other considerations. Furthermore,
when using the cupric ion at about pH 9 or above~ suitably at pH 9.5p
no chelating agent is required, because no insoluble traces can be
found in the solution. Suitably monoethanolamine or other nitrogen-
containing alkalizers, such as other alkanolamines, ammonia, etc. can
be used for adjusting the desired pH. Alkali hydroxides work well
only if a chelating agent is also employed to maintain the solution.
The basic pH has the further advantage of swelling the hair and this
allows a better dye take. In the case of using the cupric ion it is
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decided~y preferable to impregnate the hair first with the solution
containing the cupric ion and, after rinsing or blotting the hair,
impregnating it with the solution containing the 5,6-dihydroxyindole.
The intermediate rinsing or blotting of the hair surface is required
to prevent superficial dye formation which can be washed off, since
dye formation within the hair shaft itself is desired. As used
throughout the specification and the claims, in this context the term
"rinsing" is intended to include blotting, wiping and any other method
for removing a solution from the hair surface. It requires about 2-20
minutes to dye the hair to the maximum achievable depth of color when
using a metal salt promoter for melanogenesis; but when using the
cupric ion the time required is at the faster end of even this fast
time range. Therefore, as can be seen, use of the cupric ion provides
a plurality of benefits over and above those that can be achieved with
other melanogenesis promoters.
The solution containing the 5,6-dih~droxyindole is suitably at p~l
8 or above. It should preferably not exceed 9.5, since the solutions
are increasingly unstable at increasing pH. At the conclusion of
dyeing the hair black or grey, shampooing is preferred to a mere
rinse. This is, because any dye that may have formed on the hair
surface may not rinse off and then can later rub off the surface. A
shampoo will remove such surface dye and thus prevent ruboff.
The concentration of the 5,6-dihydroxyindole is not critical, but
suitably from about 0.5 to about 2% by weight of the solution can be
employed for reasons of economy and suitable control over t~e rate o~
dyeing. As indicated, the concentrations of the respective
ingredients are not critical. ThereEore, wherever a concentration is
characterized in the specification and the claims as being an
"effective amount", this characterization means that the amount
employed be sufficient for the intended purpose~ Such purpose can h~
as diverse as a different depth of shade, greater economy in cost of
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067
ingredients, different reaction rate, solution stability, and the
like. Whatever the purpose, the effectiveness of the amount of an
ingredient can be determined by routine experimentation. All
percentages throughout the specification and the claims are by weight,
unless otherwise specified.
If the shade that is desired is other than black, then the hair,
subsequent to dyeing and possible shampooing, is subjected to a
lightening step by contacting it with a dilute hydrogen peroxide
solution until the desired shade is obtained. Any suitable hydrogen
peroxide solution useful in the bleaching or lightening of hair can be
employed in this step, however, it was found th~t an H202
concentration of from about 1~ to about 6% is sufficient. In
lightening the hair from black or grey, the color will pass through
various progressively lighter shades and the process can be stopped by
rinsing the hair when it reached the shade that is desired. The
natural shade of the hair can be readily re-established after a prior
darker shade is no longer desired. The aqueous hydrogen peroxide
solution is suitably employed above pH 8, suitably at pH ~. The
relatively slow, but not too slow rate of lightening of up to 15
minutes provides suficient control to the user for stopping at any
desired shade or at the natural shade of the hair. In this manner the
competing dyeing and bleaching reactions of the prior art and the
attendant drawbacks are eliminated to provide a better, more positiv~
control over the entire process, regardless of whether the dyeing is
done in the salon or by the user.
The process of the present invention also enables the selective
coloring of different portions of the hair to achieve highlights,
streaks and other special cosmetic effects.
67
To maintain stability, suitably the 5,6-dihydroxyindole solution
is maintained at an acid pH, advantageously around pH 4.5. Further-
more, the solution at the acid pH should suitably be maintained under
anaerobic conditions, such as under nitrogen, whereby during packaging
the atmosphere above the solution in the bottle is established with
nitrogen rather than air. One method of dealing with the problem is
to maintain a small volume of nitrogen above the solution in the
bottle, the space being sufficient to allow the addition of an
~lkalizer before use. This can be, however, inconvenient, and,
therefore, suitably a concentrated, such as 12.5~, aqueous alcoholic
or entirely alcoholic solution of the 5~6-dihydroxyindole, in which it
is easily soluble, can be maintained at acidic pH in a small, full
container until it is intended to be usedO Immediately before use the
contents of this small bottle can be transferred to a larger bottle
which can contain a pre-thickened alkaline solution to obtain the
a~kaline 5,6-dihydroxyindole solution immediately before its use.
Another way is to maintain the alkalizer in a small pouch made of a
selectively soluble material and then the entire pouch can be dropped
into the space above the acidified 5,6-dihydroxyindole-containing
solution to avoid the need for the consumer being required to handle a
possibly strong alkalizer. Alternatively, when a small3 concentrated
solution of acidified 5,6-dihydroxyindole is intended to be added to
an alkaline solution, then the former could be maintained in a
selectively soluble pouch which could in its entirety be transferred
to the aqueous alkaline solution to avoid the need of the user having
to pour a liquid from one container in~o another.
It was found that adding a small amount, such as 1% by weight, of
a surfactant, such as sodium lauryl sulfate to at least one of the
metal and the 5,6-dihydroxyindole solutions, can improve the flow-on
properties of the compositions for better applicability to the hair.
Similarly, scalp staining can be reduced and the desirable ~low
properties of the solutions can b~ improved by adding a small amount,
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such as 0.5% by weight of a thickener to both of the solutions, such
as carbomer 940, a polymer of acrylic acid crosslinked with a
polyfunctional agent and sold by the Goodrich Chemical Company under
the name of Carbopol 940. The identity of other ~gents for adjusting
desirable flow properties can be determined by routine experimentation,
since such flow property-adjusting agents are well known in the field
of compounding hair treatment compositions. It is also known in the
art of hair treatment compositions that certain flow property-changing
additives may be incompatible with certain compositions. It was
found, for example, that additives such as cocamidopropyl hydroxy-
sultaine, sold by Lonza Chemical ~o. under the name of Lonzaine CS,
and hydroxypropyl methylcellulose sold by Dow Chemical Co. under the
name Methocel, were apparently not compatible with compositions of th
present invention, because the resulting color was not as deep when
these materials were included. Other ingredients known per se, such
as conditioners, perfumes~ anti-static agents and the like, can be
included in the compositions or can be subsequently applied to the
hair.
The following examples serve as further illustrations of the
present invention.
Example 1
The following promoter composition was prepared:
CuSO4-5H20 1%
carbomer 940 0.5
sodium lauryl sulfate 1%
monethanolamine to pH 9.5
water q.s. to 100
* trade mark.
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The following dye composition was prepared:
sodium acetate 1.2%
5,6-dihydroxyindole 1.2
carbomer 940 0 47
ethanol 19.7~
sodium hydroXide to pH 8.5
Hair was saturated with the catalytic composition for fi~e
minutes and then rinsed with water. Next the hair was saturated
with the 5,6-dihydroxyindole-containing composition for a period
of 5 minutes. The resulting black dyed hair was shampooed to
remove any melanin from the surface of the hair.
Example 2
Light brown hair was dyed black with the procedure of
Example 1. Subsequently the hair was saturated with à 6~ aqueous
solution of hydrogen peroxide at pH 9. After 10 minutes when the
original light brown shade of the hair was reached, the hair was
rinsed~ The same procedure was repeated but the hair was
lightened for 6 minutes to a darker brown shade. Three weeks
later the hair was further lightened for 3 1/2 minutes to its
original light brown shade.
Example 3
The same process was carried out as in Example 1, on blond
hair, except that the concentration of the 5,6-dihydroxyindole
was only 0.5~. Dyeing was carried out only for ~ minutes to a
light to medium gray color. After shampooing, a 6% aqueous
hydrogen peroxide solution at pH 9 was employed to lighten the
hair to a light brown shade within 6 minutes.
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Example 4
The copper sulfate solution of Example 1 was replaced by
employing 0.25% PeS04based on the composition premixed with
citric acid in an amount suitable to prevent precipitation of the
iron at alkaline pH, and monethanolamine was used to adjust the
pH to 9.5.
The procedure of Example 1 was repeated, except that no
carbomer 940 was contained in the 5,6-dihydroxyindole-containing
solution. The hair was exposed to the catalyst solution for 10
minutes, then rinsed and saturated with the 5,6-dihydroxyindole-
containin~ solution for 10 minutes until the initially light
brown-colored hair turned distinctly darker.
Example 5
The same procedwre as in Bxample 1 was repeated, exc~pt
that the 5,6-dihydroxyindole-containing solution was applied
first, followed, after a rinse, by the catalyst-containing
solution. The resulting color on the hair was less intense than
in the case of Example 1.
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