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Description  |
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TABLE OF CONTENTS
1. Field of the Invention ...
2. Background of the Invention ...
2.1. Use of Iodine/Iodide ...
3. Summary of the Invention ...
4. Detailed Description of the Invention ...
4.1. Reduction Systems ...
4.1.1. Sulfite or Bisulfite System ...
4.1.2. Ammonium Thioglycolate System ...
4.1.3. Monoethanolammonium Thioglycolate System ...
4.1.4. Glycerol Thioglycolate System ...
4.2. Neutralization Systems ...
5. Examples: Preparation and Methods of Use ...
5.1. Formulations ...
5.1.1. Bisulfite/Iodide ...
5.1.2. Ammonium Thioglycolate/Iodide ...
5.1.3. Monoethanolammonium Thioglycolate/Iodide ...
5.1.4. Glycerol Thioglycolate/Iodide ...
5.2. Methods of Use ...
5.3. Curling Hair Samples ...
5.3.1. Bisulfite/Iodide Treatments ...
5.3.2. Ammonium Thioglycolate/Iodide Treatments ...
5.3.3. Monoethanolammonium Thioglycolate/Iodide Treatments ...
5.3.4 Glycerol Monothioglycolate/Iodide Treatments ...
6. Effect of Iodide Systems in Controlling Hair Damage ...
7. Salon Tests on Hard-to Curl Hair ...
7.1. Fragile Hair ...
7.2. Oriental Hair ...
7.3. Hard-to-Perm Caucasian Hair ...
8. Example: Straightening Hair ...
9. Claims
1. FIELD OF THE INVENTION
The present invention is directed to new and improved methods of
permanently waving hair, and novel compositions of matter useful in such
improved methods. The novel compositions may also be useful for altering
the shape of hair by relaxing or straightening naturally or artifically
waved hair.
2. BACKGROUND OF THE INVENTION
Conventional methods for permanently waving keratinous fibers, particular
hair, generally consist of a two stage process. Initially the hair is
shampooed, and mechanically positioned into the configuration or shape
desired. Generally this is acheived by wrapping the hair around cylinders
(termed "rollers") of the appropriate size to either impart a curl or wave
or to straighten waved hair.
In the first stage of process, referred to as the reduction stage, the
disulfide linkages (S--S) of the keratin fiber are opened (reduced to two
mercaptan groups), with the aid of reducing agents, including
thioglycolates, sulfites, and bisulfites, etc. Depending upon the systems
used, the hair is exposed either to acidic or alkaline values of pH.
Thereafter, the hair is rinsed extensively and subsequently treated with a
mild oxidizing agent in a second stage operation, referred to as a
neutralization stage, to form new S--S linkages and to impart the desired
configuration to the hair. Generally used neutralizing agents include
hydrogen peroxide and sodium bromate (Robbins, Chemical and Physical
Behavior of Human Hair, Van Nostrand Reinhold Company, New York (1979)).
Conventional techniques, however, have suffered from a number of
disadvantages. In particular, thiol containing compositions suffer from a
persistent disagreeable sulfur odor. Other compositions suffer from the
irritating odor of ammonia when utilized at alkaline values of pH. Sulfite
and bisulfite systems when used for "home perms" require an extensively
long period of time in contact with the hair, e.g., one hour or so, and
typically produce curls of less than professional standards. Additionally,
since many of the other conventional ingredients are caustic to both hair
and skin, safety considerations do not allow for home use formulations as
concentrated as typically used in professional salons. Consequently, such
"home perm" systems are not as effective, i.e., curl is not as tight and
does not last as long, as available professionally. More importantly, the
conventional systems tend to damage the hair (presumably through
hydrolysis of peptide and amide linkages), particularly if left in contact
with the hair for an extended time. The permed hair generally becomes
brittle, dry, and loses agreeable tactile quality.
2.1. USE OF IODINE/IODIDE
Conventional techniques for hair waving or straightening have not involved
the use of water soluble-iodide salts as described herein according to the
preferred embodiment of the present invention.
Use of a mixture of iodine/iodide for treating hair for other purposes has,
however, been previously described. In particular, Kritchensky (U.S. Pat.
No. 2,153,762 issued Apr. 11, 1939) described use of a mixture of iodine,
potassium iodide and sodium chloride as a first step prior to a lustering
operation for improving the luster and decreasing the tendency of wool or
hair to curl or spot when exposed to moisture. Kritchensky stated that
absorption of the iodine in the mixture was necessary for reaction with
unsaturated bonds in the hair to make the hair coarse and non-curling.
U.S. Pat. No. 3,824,304, issued to Villanueva on July 16, 1974, describes
use of a tincture of iodine, i.e., a mixture of iodine and sodium iodide
in an alcoholic solvent, to condition hair.
3. SUMMARY OF THE INVENTION
The present invention involves novel formulations that are useful for
permanently altering the shape or configuration of keratinous fibers,
particularly hair, or fur. The formulations and methods of use described
herein are more efficient and represent distinct improvements over
conventional techniques of permanent hair or fur waving and relaxing.
According to the present invention, a heretofore unusable reducing agent
(RA.sub.1), that has rapid kinetics but not necessarily a useful
equilibrium constant for tne cleavage of disulfide linkages in keratin, is
combined with a conventionally used reducing agent (RA.sub.2) that has a
usefully high equilibrium constant but not necessarily rapid reaction
kinetics. According to the inventor's theoretical understanding of the
chemistry involved, the primary agent for cleaving the disulfide linkages
is now RA.sub.1, which is very rapidly and substantially completely
regenerated from its oxidized form by RA.sub.2, which is consumed in the
process. It is to be understood, however, that successful practice of the
inventions described herein does not depend on the correctness of such
theoretical understanding, and that the invention shall not be limited to
any particular chemical mechanism. Practice of the methods described
herein and use of the formulations of the invention result in the
advantages described, independent of such theoretical concerns.
In the preferred embodiment of the present invention, the regenerable
reducing agent is a water-soluble iodide salt including, but not limited
to: simple salts such as potassium iodide, sodium iodide, and ammonium
iodide. In other embodiments, potassium ferrocyanide, sodium bromide and
antimony (III) potassium tartrate may be used as the regenerable reducing
agent, but they are less effective than iodides.
The combinations of the present invention are useful in improving the
kinetics of the reduction stage in permanent waving and hair straightening
systems. When used in systems containing sulfites or bisulfites, the
improvement is such that these odorless systems can produce professional
quality permanent waves, which was not possible heretofore.
The combinations of the present invention when used in thioglycolate
systems have the very important and surprising benefit of significantly
reducing the usual hair damage associated with waving, because:
(a) The caustic thioglycolic reducing agents can be used at lower
concentrations, because of the improved kinetics.
(b) If used at conventional concentrations, such caustic agents can be left
in contact with the hair for a shorter period of time, because of improved
kinetics.
(c) Overprocessing is avoided because the consumable thioglycolate reducing
agents are rapidly used up in the process of reducing iodine to iodide,
which reaction is favored over the thioglycolate reaction with the hair.
(d) Most importantly and surprisingly, the regenerable reducing agent which
is primarily responsible for the disulfide cleavages is apparently very
selective for this reaction since it is innocuous at the concentrations
used as far as hair damage is concerned.
In addition, because of the improved kinetics of the reactions of this
invention, the gentle and slow acting monoethanolammonium thioglycolate,
which has heretofore been largely limited to home waves, can now
surprisingly be used in professional salon cold waves as a practical
substitute for the ammonia thioglycolate system, thereby eliminating the
irritating ammonia fumes associated with such systems.
4. DETAILED DESCRIPTION OF THE INVENTION
As described supra in Section 2, the conventional method for permanently
waving hair fibers consists in a first reducing stage operation in which
the disulfide linkages (S--S) of the keratin fiber are broken with the aid
of a reducing agent. Thereafter, the hair is preferably rinsed well and
subsequently treated in a second stage operation with a neutralizing agent
to form new S--S linkages of the keratin to impart to the hair the desired
configuration or shape.
4.1. REDUCTION SYSTEMS
According to the present invention in the first reducing stage of the
two-stage process for hair treatment, a regenerable reducing agent
(RA.sub.1) that has rapid kinetics, but not necessarily a useful
equilibrium constant for the reaction in which the disulfide linkages of
keratin in hair fibers are reduced, is combined with a consumable reducing
agent (RA.sub.2) that has a usefully high equilibrium constant, but not
necessarily rapid reaction kinetics for the keratin reduction reaction.
By "useful" as applied to the equilibrium constant is meant that if the
reaction were allowed to reach equilibrium, the amount of reduced keratin
present, when subsequently oxidized (neutralized), would provide an
acceptable curl. In this context "useful" does not indicate that the
reaction would occur within an acceptable time frame for purposes of
curling or straightening hair or fur. Generally, an acceptable time frame
would be less than about one hour, preferably about ten to twenty minutes.
Conversely, a reaction which does not have a useful equilibrium constant
would not, if allowed to reach equilibrium, provide a sufficient amount of
reduced keratin to impart an acceptable curl after subsequent
neutralization.
By the term "rapid reaction kinetics" is meant that the reduction reaction
is fast enough to provide, within an acceptable time frame, sufficient
reduced keratin which, after subsequent neutralization, would provide an
acceptable curl. Again, an acceptable time frame would be about one hour,
preferably ten to twenty minutes.
Based upon the inventor's proposed theoretical mechanism of this reaction,
it is presumed that the oxidized form of the regenerable reducing agent
(RA.sub.1-ox) is rapidly and essentially completely reduced to RA.sub.1 by
the consumable reducing agent. While the consumable reducing agent
apparently does some useful work of cleaving disulfide bonds, the main
work surprisingly seems to be accomplished by the regenerable reducing
agent, which by itself is not capable of cleaving the disulfide bonds in a
detectable amount because of its very low equilibrium constant for this
reaction. (In fact the reverse reaction, neutralization with iodine
solution, proceeds very rapidly.) As shown in Table III (see Section
5.3.2), for example, ammonium thioglycolate systems, which on their own
produce poor curls in five minutes, when combined with potassium iodide
produce very good curls in the same amount of time.
Increased efficacy of formulations of the present invention is conferred by
the combination of a consumable reducing agent with the regenerable
reducing agent. Specifically, according to the preferred embodiment, a
water-soluble iodide salt such as simple iodide salts including, but not
limited to potassium iodide (KI), sodium iodide (NaI), or ammonium iodide
(NH.sub.4 I), is utilized as the regenerable reducing agent. Combination
of the regenerable and consumable reducing agents enhances the efficacy of
compositions containing only the corresponding consumable reducing agent
by permitting the reduction of disulfide linkages of the keratin to
proceed at a faster rate.
Moreover, the hair is damaged less because the damaging consumable reducing
agent in the combinations of the present invention: (a) can be in contact
with the hair for a shorter period-of time; (b) may be used in lower or
more dilute concentrations; and (c) presumably is consumed rapidly by the
oxidized-form of the regenerable reducing agent which reacts more
selectively. Hence, the combinations of the present invention inherently
protect against overprocessing of the hair because the damaging consumable
reducing agent is rapidly consumed by the iodine in the process while the
regenerable reducing agent, which is primarily responsible for the
disulfide cleavage, is apparently very selective for this reaction since
it is innocuous at the concentrations employed as far as hair damage is
concerned. Other advantages of specific embodiments are indicated infra.
The chemical reactions in the first reduction stage operation of hair
treatment according to the present invention may be represented by the
generalized equations as follows:
##STR1##
wherein the equilibrium constant for the reaction is K.sub.1 (eq), and
k.sub.4 and k.sub.5 represent the forward and reverse reaction rate
constants. "Keratin" represents the disulfide-bound keratin protein, and
"Keratin-reduced" represents reduced protein and "RA.sub.1-ox " represents
the oxidized form of reducing agent RA.sub.1.
The equilibrium constant for the reaction of equation (1) may be computed
as follows:
##EQU1##
The expression (2) above may be rewritten such that
##EQU2##
If the value of [RA.sub.1-ox ] is made very small, i.e., by reduction by
the consumable reducing agent, then the corresponding value of
##EQU3##
becomes usefully large, that is, the reaction of Equation (1) would be
"driven" in favor of Keratin-reduced, and sufficient amounts of reduced
keratin would be formed such that after neutralization an acceptable curl
results.
The reaction of the regeneration of the regenerable reducing agent by the
consumable one is represented as follows:
##STR2##
wherein K.sub.2 (eq) is the equlibrium constant for the reaction and
k.sub.6 and k.sub.7 represent the forward and reverse reaction rate
constants.
The equilibrium constant for the reaction of equation (4) may be computed
as follows:
##EQU4##
Expression (5) above may be rewritten as
##EQU5##
Substitution of this ratio into expression (3) above gives
##EQU6##
The equation for the reaction of the consumable reducing agent with keratin
is
##STR3##
wherein the equilibrium constant for the reactions is K.sub.3 (eq) and
k.sub.8 and k.sub.9 represent the forward and reverse reaction rate
constants.
The equilibrium constant for the reaction of Equation (8 ) may be computed
as follows:
##EQU7##
Equation (9) may be rewritten as
##EQU8##
Comparing Equations (7) and (10), it can be seen that
(11) K.sub.1 (eq).times.K.sub.2 (eq)=K.sub.3 (eq)
In addition to Equation (11), the constraints upon the choice of particular
compounds for RA.sub.1 and RA.sub.2 include the following:
(i) K.sub.3 (eq)>K.sub.1 (eq)
As described above, RA.sub.2 has a useful equilibrium constant for the
reduction of disulfide bonds, but the reaction may not proceed rapidly
enough. On the other hand, no matter how long one observes the reaction of
the reduction of Keratin by RA.sub.1, it will not proceed to an
appreciable extent since the equilibrium constant is so small. From
effective conventional compositions containing a single reducing agent,
such as thioglycolate, the equilibrium constant for reduction of Keratin
may be estimated to be in the range of about 10.sup.-1 to 10.
Thioglycolate for example, has an equilibrium constant of approximately 1.
Since RA.sub.1 alone does not result in appreciable reduction of keratin,
i.e., K.sub.1 (eq) is very small, for example, 10.sup.-10 to 10.sup.-20,
K.sub.3 eq is greater than K.sub.1 (eq).
(ii)k.sub.6 >k.sub.5
In order to "drive" the reduction of Keratin by RA.sub.1 in favor of
producing Keratin-reduced, the [RA.sub.1-ox ] must be reduced by the
action of RA.sub.2 in accordance with Equation (4). Thus, k.sub.6 must be
very large relative to k.sub.5.
(iii) K.sub.2 (eq) >K.sub.1 (eq)
In accordance with Equation (11), when K.sub.3 (eq)>K.sub.1 (eq) [(i)
above], then K.sub.2 (eq)>K.sub.1 (eq). Based upon the relationships among
the three equilibrium constants, K.sub.2 (eq) would be expected to be very
large, for example, in the range of to 10.sup.10 to 10.sup.20.
(iv) k.sub.6 >k.sub.8
The qualitative description for this constraint is that the rate of
regeneration of RA.sub.1 by RA.sub.2 is greater than the rate of reduction
of Keratin by RA.sub.2.
(v) k.sub.4 >k.sub.8
Both of constraints (iv) and (v) must be true in order for one to observe
an effect upon addition of RA.sub.1. If k.sub.8 were larger than k.sub.4
and k.sub.6, the reaction of k.sub.8 would be the fastest reaction and
addition of RA.sub.1 would have no effect.
Since the "concentration" of disulfide bonds of keratin can not be
accurately estimated, and since such a figure would necessarily vary
depending upon hair type and from individual to individual, numbers for
the equilibrium constants K.sub.1 (eq) and K.sub.3 (eq) can only be
approximated.
The relationship of Equation (11) among the three equilibrium constants
always holds by chemical law, and the critical factors are the kinetics of
K.sub.1 (eq) and K.sub.2 (eq) relative to those of K.sub.3 (eq). What is
truly surprising is that the reaction of K.sub.1 (eq) with its minute
equilibrium constant should have a k.sub.4 that is greater than k.sub.8.
According to the preferred embodiment of the present invention, the
regenerable reducing agent (RA.sub.1) is a water-soluble iodide salt such
as simple iodide salts including potassium iodide (KI), sodium iodide
(NaI), or ammonium iodide (NH.sub.4 I). When KI is utilized as RA.sub.1,
the kinetics of expression (1) above are excellent in that the reaction
proceeds rapidly and iodide diffuses readily through the hair.
Other salts which may be used as regenerable reducing agents include, but
are not limited to: ferrocyanides, bromides, and antimony (III) tartrates.
In comparison with soluble iodide salts, the latter salts are far less
effective being fair, weak and weak, respectively, relative to iodide in
their enhancing effects on hair waving compositions. Although potassium
thiocyanate (KSCN) is close in redox and electrolytic properties to KI,
KSCN is not effective at all in the compositions of the present invention.
Similarly, potassium chloride is not effective at all. Other common salts
which also are not effective include various sulfates and nitrates.
To evaluate quantitatively the contribution of KI to increasing the perming
rate and degree of curl formation, the following experiments were
performed. Exactly 1 gm samples of untreated brown hair were shampooed,
blotted dry, and wrapped on rollers. A total of 10 samples were prepared
in this way. Five of them were impregnated with exactly 1 ml each of 1.0 M
monoethanolammonium thioglycolate adjusted to pH 9.3 with
monoethanolamine. The remaining glycolate solution was made 0.3 M in KI
and the five remaining hair samples impregnated with exactly 1 ml each of
this solution. All 10 samples were allowed to react at ambient temperature
(approx. 75.degree. F.) for 5 minutes and then quenched and allowed to
soak in 600 ml of water. Each sample was well agitated to thoroughly rinse
out unreacted agents. The amount of unreacted thioglycolate was determined
by titration with standard iodine solution. For the five samples
containing no KI, the average thioglycolate consumption was 36%. For the
samples containing KI, the average consumption was 54%. An additional 2
samples were impregnated with 1.0 M thioglycolate (pH 9.3) solution, one
with and one without KI, and allowed to set for 30 minutes. The
thioglycolate consumption was 60% with KI and 63% without KI.
All the samples were neutralized with 10% NaBrO.sub.3 solution for 5
minutes, unrolled, rinsed, and allowed to air dry.
All the samples containing KI yielded professional quality curl formation
with no discernible hair damage. The 5 samples treated without KI yielded
curls of poor quality. The sixth sample without KI which was allowed to
react for 30 minutes yielded a well-formed curl, but the hair showed
discernible damage as evidenced by rough, stiff tactile qualities.
In these experiments, the addition of KI increased the rate and quality of
curl formation and eliminated hair damage. One can reasonably infer from
these experiments that in the presence of KI and the thioglycolate
compound, the preferred reaction is the splitting of the disulfide bonds
by the iodide-iodine regeneration reaction. Thus, the thioglycolate would
be consummed to regenerate iodide.
This was confirmed in similar experiments in which data was obtained at
various reaction times from 1.5 to 8 minutes. Analysis of these data
establish that the reaction rate in the presence of 0.3 M KI is 3 times as
fast as is found with thioglycolate alone. That is, in the
thioglycolate-iodide system 75% of the disulfide bond splitting is a
result of the iodide interaction.
According to the present invention, the compounds listed in Table I (which
should not be considered an exhaustive list) may be utilized as consumable
reducing agents. As illustrated in Table I, a number of these substances
may be used as reducing agents in the absence of a regenerable reducing
agent. Enhanced results are achieved when each of the listed compounds is
combined with a regenerable reducing agent as described supra. In all the
systems listed in Table I there is a substantial improvement when KI is
used due to the improvement in kinetics.
TABLE I
______________________________________
COMPOUNDS PROVIDING CONSUMABLE
REDUCING AGENTS
Activity Without Regener- - Compound able Reducing
Agent
______________________________________
Ammonium thioglycolate
good
Glycerol thioglycolate
good (+ heat).sup.a
Monoethanolammonium thioglycolate
medium
Sodium sulfite fair
Sodium bisulfite fair +
Sodium hydrosulfite fair
Ammonium sulfite fair
Ammonium bisulfite fair
Potassium sulfite fair
Potassium bisulfite fair +
Sodium formaldehyde bisulfite
poor -
Sodium formaldehyde sulfoxylate
poor -
______________________________________
.sup.a Indicates that heat activation is required.
4.1.1. SULFITE OR BISULFITE SYSTEM
In one embodiment of the present invention, either the sulfite
(SO.sub.3.sup..dbd.) or bisulfite (HSO.sub.3.sup.-) ion is utilized as the
consumable reducing agent (RA.sub.2). The useful concentration range of
RA.sub.2 is about 0.3-2.0 M, the preferable concentration being about 0.7
to 1.5 M. Preferred cations include: potassium (K.sup.+), ammonium
(NH.sub.4.sup.+), sodium (Na.sup.+) and a mixture of Na.sup.+ and
NH.sub.4.sup.+. The preferred regenerable reducing agent (RA.sub.1) is the
soluble iodide ion. The useful concentration range for iodide is about
0.05-1.0 M, preferably about 0.15-0.4 M. Any of the cations as used for
the RA.sub.2 may be utilized for the RA.sub.1. The useful pH range for the
combination of reducing agents is about 4-10, preferably about 6-7.5.
When either SO.sub.3.sup.= or HSO.sub.3.sup.- is used as the RA.sub.2, the
composition is useful particularly when employing a heat-activated method
of application. The heat may be supplied by use of a dryer with a cap or
by use of body heat contained with a cap. In the latter instance, the
composition is allowed to remain on the hair for a somewhat longer period
of time, e.g., about 15-30 minutes, compared to about 10-20 minutes when a
dryer is used. A permanent wave that meets professional standards is
achieved.
In practice, when K.sup.+ is utilized as the cation, the composition of the
present invention is substantially odorless at all values of pH in the
preferred range, and has excellent diffusional properties so that the
active ingredients are rapidly delivered to the S--S linkage sites of the
hair. Thus, this embodiment of the present invention offers a number of
distinct additional advantages over conventional techniques, particularly:
(a) lack of persistent unpleasant odor; and (b) more rapid reaction rate
which reduces processing time and (c) most importantly and for the first
time, enhanced curl formation that is equivalent to that achieved by
thioglycolic acid systems.
In practice, when either NH.sub.4.sup.+ or a mixture of NH.sub.4.sup.+ and
another cation such as Na.sup.+ is utilized as the cation, the
disagreeable odor of sulfur dioxide is detected when used below the
preferred range of pH, and the odor of ammonia is detected when used above
the preferred range of pH.
4.1.2. AMMONIUM THIOGLYCOLATE SYSTEM
In another embodiment of the present invention, the thioglycolate
(HSCH.sub.2 COO.sup.-) ion is utilized as the consumable reducing agent
(RA.sub.2). The useful concentration range is about 0.4-1.2 M, preferably
about 0.5-1.0 M. The preferred cation is NH.sub.4.sup.+. The preferred
regenerable reducing agent (RA.sub.1) is iodide. The useful concentration
range of iodide is about 0.05-1.0 M, preferably about 0.15-0.4 M. The same
cation as used for the RA.sub.1 may be utilized for the RA.sub.2. The
useful pH range for this combination of reducing agents is about 9.0-9.5.
The composition has a distinct odor of ammonia at such pH values. Also
present is the characteristic odor of sulfur of thioglycolate
compositions. This thioglycolate odor persists for a substantial period of
time post-treatment and is particularly noticeable and objectionable when
the hair is damp.
When ammonium thioglycolate is used as the RA.sub.2, and the pH adjusted to
from 9.0-9.5 with ammonia, this composition is useful particularly when
employed as a "cold wave" system. Thus, the composition is generally
applied to and reacted with the hair at ambient or room temperature.
When iodide is used as the RA.sub.1, the composition is allowed to remain
on the hair for about 3-10 minutes. This represents a distinct advantage
over conventional ammonium thioglycolate systems which require contact
with normal hair for about 10-30 minutes.
The composition of this embodiment represents distinct improvements over
conventional ammonium thioglycolate systems because the thioglycolate (a)
is in contact with the hair for a shorter time period; and/or (b) can be
used at lower concentration (see Table III, Section 5.3.2). Moreover, the
present composition offers inherent protection against overprocessing the
hair because the damaging ammonium thioglycolate is so rapidly consumed in
the course of regenerating the iodide and cleaving disulfide bonds. This
is particularly important under all conditions of use contemplated for the
composition, since the major negative side effect of permanent waving is
hair damage. The present invention also guards against aggravated hair
damage resulting from inexperience, carelessness, and too concentrated
solutions.
4.1.3. MONOETHANOLAMMONIUM THIOGLYCOLATE SYSTEM
In another embodiment of the present invention the thioglycolate ion
(HSCH.sub.2 COO.sup.-) is also utilized as the consumable reducing agent
(RA.sub.2). The useful concentration range of HSCH.sub.2 COO.sup.- is
about 0.4-1.2 M, preferably about 0.7-1.2 M. The cation for RA.sub.2 in
this embodiment is the monoethanolammonium ion. The preferred regenerable
reducing agent (RA.sub.1) is iodide. The useful concentration range for
iodide is about 0.05-1.0 M, preferably 0.15-0.4 M. Useful cations for the
RA.sub.1 include Na.sup.+ and K.sup.+. The preferred composition should
be adjusted to pH about 9.0-9.5 with monoethanolamine.
In practice, the monoethanolammonium thioglycolate composition of this
embodiment is particularly useful when applied as a "cold wave", i.e., at
ambient or room temperature. When thus used, the composition can be used
to achieve a permanent wave that meets professional standards and the
objectionable, irritating fumes of ammonia are eliminated. Heretofore,
monoethanolammonium thioglycolate compositions have been largely
restricted to home perms.
4.1.4. GLYCEROL THIOGLYCOLATE SYSTEM
In still another embodiment of the present invention, the glycerine ester
of thioglycolic acid, glycerol monothioglycolate, is utilized as the
RA.sub.2. The preferred range for this RA.sub.2 is about 0.6-1.5 M. The
preferred RA.sub.1 is the iodide ion which is utilized in the form of
soluble alkaline salts such as Na.sup.+, K, and NH.sub.4.sup.+ and the
like. In this system, the RA.sub.1 and RA.sub.2 must be mixed together
just prior to use because glycerol thioglycolate hydrolyzes in water. The
preferred pH range is about 6.7-7.3, and aqueous ammonia is the preferred
base used to adjust the value of pH.
In practice, the glycerol monothioglycolate composition of this embodiment
may be advantageously be applied either as a "cold wave" or as a
heat-activated formulation. Heretofore, this material was useful primarily
only when heat activated.
4.2. NEUTRALIZATION SYSTEMS
As explained previously, a second stage operation comprising application of
a neutralizing agent is necessary to form new S--S linkages of the keratin
fibers in order to maintain the hair in the desired curled or straight
configuration.
According to the present invention in the second stage of operation, the
preferred neutralizing agent is aqueous sodium bromate (NaBrO.sub.3).
In practice, the neutralization stage of operation is performed as follows:
after treatment of the hair with a reducing composition, the hair is
rinsed thoroughly to remove the reducing agents, blotted, and a
neutralizing agent applied to the hair which is mechanically maintained in
the desired configuration. After about five minutes, the hair is briefly
rinsed, released, i.e., unwrapped from rollers, rinsed again, and allowed
to dry. When the hair has been treated with an alkaline composition, it
may initially be rinsed for about three minutes. When the hair has been
treated with an acid composition, the hair is less porous and should be
rinsed initially for at least five minutes.
As a practical consideration, when an acid composition at a pH less than
about 6.5-6.7 containing iodide as the regenerable reducing agent has been
used, it is important to rinse thoroughly. For example, if a sulfite
composition described supra in Section 4.1.1 is used, a small amount of
iodine may be formed by oxidation of any residual iodide present. The
presence of such iodine may be detected as a slight yellow color on any
end papers used to wrap the hair. At pH about 6.7 or higher, such reaction
does not occur with bromates. With the commonly used acidified hydrogen
peroxide (H.sub.2 O.sub.2) neutralizers, iodine formation occurs.
According to the present invention, other agents that can be utilized as
neutralizing agents for the second stage when iodide is used as the
regenerable reducing agent include: sodium or potassium antimony (V)
tartrate, and a composition comprising a solution of H.sub.2 O.sub.2 to
which is introduced at the time of use a "protective" reducing agent which
reacts only slowly with H.sub.2 O.sub.2 but rapidly with iodine. The
protective reducing agent acts to reduce any iodine formed to iodide. Such
reducing agents include ascorbic acid and carbazide. In practice, a
solution of less than 3% H.sub.2 O.sub.2 containing such reducing agent is
used. In general, about 1-5% ascorbic acid or carbazide is sufficient. The
useful pH range is about 1.5-3.8, preferably about 1.5-2.5. The preferred
pH is generally achieved by the addition of phosphoric acid.
The neutralizing compositions of the present invention can also contain a
thickening agent such as carboxymethyl cellulose, conditioning agents such
as mineral oil, lanolin, or other suitable quaternary ammonium salts.
Further the composition can also contain certain other conventional
cosmetic adjuvants such as perfume, dyes, stabilizers, preservatives and
surfactants.
The following examples are given for the purpose of illustration and not by
way of limitation on the scope of the invention.
5. EXAMPLES: PREPARATION AND METHODS OF USE
5.1. FORMULATIONS
Examples presented below demonstrate formulations for reducing compositions
that were prepared as described supra in Section 4. The active ingredient
listed represents the initial starting ingredient used to prepare the
formulation. In each case, sodium laureth sulfate (Henkel Corp.) (0.5% by
weight) was added to the composition as a wetting agent or surfactant.
There was, however, nothing to indicate that such surfactant is essential
to the activity of the compositions.
5.1.1. BISULFITE/IODIDE
Representative bisulfite/iodide reduction systems include:
______________________________________
Concentration
Active Ingredient
(Molarity)
______________________________________
Sodium bisulfite 1.0
Potassium Iodide.sup.a
0.3
Ammonia (aqueous).sup.b
______________________________________
.sup.a USP Grade (E & F King)
.sup.b Added as reagent grade (28%) (Fischer Scientific) to adjust pH to
6.8.
5.1.2. AMMONIUM THIOGLYCOLATE/IODIDE
Representative thioglycolate/iodide reduction systems include:
______________________________________
Concentration
Active Ingredient (Molarity)
______________________________________
Ammonium thioglycolate.sup.a
1.1
Potassium Iodide 0.3
Ammonia (aqueous).sup.b
______________________________________
.sup.a Added as cosmetic grade, i.e., 60% contained thioglycolic acid
(Evans Chemical).
.sup.b Added as reagent grade (28%) (Fischer Scientific) to adjust pH to
9.3.
5.1.3. MONOETHANOLAMMONIUM THIOGLYCOLATE/IODIDE
Representative monoethanolammonium thioglycolate/iodide reduction systems
include:
______________________________________
Concentration
Active Ingredient (Molarity)
______________________________________
Monoethanolammonium
1.1
thioglycolate.sup.a
Potassium Iodide 0.3
Monoethanolamine.sup.b
______________________________________
.sup.a Added as 39.2% contained thioglycolic acid (Evans Chemical).
.sup.b Reagent grade (Fischer Scientific) added to adjust pH to 9.3.
5.1.4. GLYCEROL THIOGLYCOLATE/IODIDE
Representative glycerolthioglycolate/iodide reduction systems include:
______________________________________
Concentration
Active Ingredient (Molarity)
______________________________________
Glycerol Monothioglycolate.sup.a
1.1
Potassium Iodide 0.3
Ammonia (aqueous).sup.b
______________________________________
.sup.a Added as cosmetic grade, i.e., 80% glycerol monothioglycolate in
glycerine (Evans Chemical).
.sup.b Added as reagent grade (28%) (Fischer Scientific) to adjust pH to
6.8.
5.2. METHODS OF USE
The following experiments demonstrate methods of application and results
obtained when using the compositions according to the present invention.
In each of the experiments 0.5 gm of Caucasian hair (about 7 inches in
length) (DeMeo Brothers, New York, NY) was secured at one end with a
plastic tab, shampooed using Purifying Shampoo.TM. (Eljenn International
Corp., Newton, MA), rinsed with water, blotted and wrapped tightly, using
end papers, around rollers (about 0.5 inch diameter). The appropriate
reducing composition was applied, allowed to react under conditions of
time and temperature as specified, and the hair was rinsed in running
water for one minute.
Ambient or room temperature was about 75.degree. F. When experiments were
performed at room temperature, the hair samples were not enclosed. When
experiments were performed at higher temperatures, the hair samples were
enclosed in a plastic bag which was then warmed to the desired temperature
using a salon-type hair dryer.
In all cases, the neutralizing composition comprised a commercially
available aqueous solution of sodium bromate (about 10%) at a pH of about
7.5 (AmeriBrom Co.).
After the hair was rinsed, the sample was blotted, the neutralizing
composition applied and allowed to react with the hair for about 5
minutes. The hair was then rinsed briefly, unwrapped and rinsed well in
running water. The unwrapped hair was then blotted and allowed to air dry.
The "shape", "strength" and "springiness" of tne curl achieved was then
evaluated. The "shape" of the curl refers to the waved configuration
perceptible in the hair sample. The "strength" of the curl refers to
persistence of the curl following a single shampooing 48 hours
post-treatment. The "springiness" of the curl refers to the liveliness
with which a | | |
