WO1999060993A1

WO1999060993A1 - Compositions and methods for removing the color from permanently dyed keratin fibers

Info

Publication number: WO1999060993A1
Application number: PCT/US1999/011741
Authority: WO
Inventors: Tony R. Adair; Donald R. Cowsar
Original assignee: Carson Products Company
Priority date: 1998-05-29
Filing date: 1999-05-27
Publication date: 1999-12-02
Also published as: EP1082087A4; AU4211999A; EP1082087A1

Abstract

The method and compositions of this invention provide a means of removing dyes from keratin fibers under relatively mild conditions. This dye removal is accomplished through the use of compositions containing bicarbonate salts in conjunction wiht oxidizing agents, such as hydrogen peroxide to remove oxidative dye molecules not only from the surface of dyed keratin fibers, but also dye molecules deposited within the cortex of the fiber. The present invention is especially useful to people who have dyed their hair and wish to return their hair to its original color or for people who wish to have variegated hair coloring.

Description

COMPOSITIONS AND METHODS FOR REMOVING THE COLOR FROM PERMANENTLY DYED KERATIN FIBERS

FIELD OF INVENTION The present invention relates to the removal of color from dyed keratin fibers, such as human hair or wool, with compositions containing bicarbonate salts and hydrogen peroxide. The present invention is capable of providing a degree of lift in previously dyed keratin fibers which, heretofore, has not been possible under mild reaction conditions. Further, the invention described herein is especially suitable for use on keratin fibers which were chemically treated prior to subsequent dyeing.

BACKGROUND OF THE INVENTION

The use of dyes to change the color of keratin fibers has been known for centuries. Natural dyes from animal and plant sources were first used to dye keratin fibers. Later, synthetic dyes largely replaced natural dyes because synthetic dyes provided a more consistent and predictable coloring of the keratin fiber. One example of the use synthetic dyes is the coloring of human hair, wool, and furs with oxidative dyes.

Use of oxidative dyes to change the color of keratin fibers involves the use of hydrogen peroxide or an agent capable of producing hydrogen peroxide in solution, and small compounds, called dye intermediates. The hydrogen peroxide is admixed with the dye intermediates just prior to application to the keratin fiber. Hydrogen peroxide causes the small dye intermediates to couple inside the keratin fiber forming a large colored molecule. This colored molecule imparts color to the keratin fiber and is of sufficient size that it cannot diffuse out of the fiber without further chemical treatment. A single oxidative dye treatment lasts from 10 to 30 minutes with the more customary treatments ranging in length from 20 min to 30 min. While fairly straight forward, this process is not without consequence. The oxidizing agent, in this example hydrogen peroxide, can also weaken the keratin fiber by attacking the proteins which give the hair it's structural integrity. In fact, a number of factors combine to determine whether or not the dyed fibers will be excessively damaged. These include the concentration of the oxidizing agent, the duration of the treatment, and most importantly the initial condition of the fiber. Those skilled in the art know that keratin fibers which have already been weakened by prior chemical or mechanical treatments, can be severely damaged, sometimes to the point of breakage, by treatment with oxidizing agents.

Human hair will be used as an example of such keratin fiber for demonstration purposes. The importance of hair to the human psyche is evident by the multitude of different methods available for changing its appearance. Through the ages different methods of coloring, straightening, curling, and otherwise changing the appearance of the hair have been developed. While bleaching and coloring of hair are among the most widely practiced modifications to human hair today, other treatments are also used to obtain the desired "look". Curly hair is physically or chemically straightened, and straight hair can be physically or chemically curled. Each of these treatments causes some weakening of the proteins which give hair its structural integrity and great care must be taken to minimize excessive damage to the fiber.

Sometimes, fibers dyed with an oxidative dye are found to have an undesirable coloration, a condition which could be remedied by removal of the dye molecules. Current compositions containing hydrogen peroxide alone, or in combination with penetration enhancers like ammonia, fail to remove dye molecules from keratin fibers. However, the present art does describe the use of "boosters" which, when added to a bleaching composition containing hydrogen peroxide, remove dye molecules from keratin fibers. The boosters of current art are typically salts of peroxy acids. Although percarbonates and perborates have been suggested as boosters for lifting hair, the most commonly employed boosters are persulfate salts. Several persulfate salts are currently employed in dye removal compositions to provide a degree of lift in dyed hair in excess of that obtained when hydrogen peroxide and ammonia are used alone. These include ammonium persulfate, potassium persulfate, and sodium persulfate. Typically, these salts or blends of these salts are packaged separately from the hydrogen peroxide. In use, a packet of persulfate is added to the hydrogen peroxide immediately before the mixture is applied to the hair. Unfortunately, those skilled in the art also know that persulfates are among the most damaging oxidative agents which can be applied to the hair. The use of persulfate boosters to remove dye molecules from hair weakens the fiber because of uncontrolled side reactions with the proteins which give the fiber its structural integrity. Persulfates can be especially damaging to hair which has received a permanent wave or has been chemically straightened. Persulfate boosters also present many problems for the product manufacturer and the consumer as well.

Persulfates are very reactive oxidizing agents. This reactivity causes problems in the storage, handling and shipping of these materials. Manufacturers of hair color products often must rely on contract packagers for the preparation of booster packets. Those manufacturers who chose to prepare booster packets must invest a great deal of time, energy, and equipment in ensuring the safe handling and shipping of these materials. The end result of this effort is an increased cost of manufacturing for color-removal products which require a persulfate booster.

The separate packaging made necessary by the reactivity of persulfate boosters also raises safety concerns for consumers. Persulfate boosters tend to be irritating and even toxic if ingested. The small packets of persulfate booster employed in the current art could easily be opened and ingested by children. Further, the opening of booster packets can cause the powdered persulfates to become airborne. Particles of persulfate boosters which come into contact with the eyes, skin, and mucous membranes can easily cause burns or inhalation-related illnesses.

The use of persulfate boosters presents further problems in actual use. The boosters of the current art are somewhat difficult to dissolve. The mixture of hydrogen peroxide and these persulfate boosters must be shaken until the persulfates are fully dissolved. Thus the difficulty in dissolving persulfates causes excessive foaming of the product and builds up pressure inside the mixing vessel. Therefore, the violent, involuntary evolution of product from the container represents a possible health hazard to the user. Further, persulfate boosters often enhance the "chemical" odor of the finished blend making the color-removal treatment less pleasant for the consumer.

Surprisingly, the inventors have discovered that a degree of dye removal comparable to and in some instances superior to that obtained with a persulfate booster/peroxide combinations can be obtained under relatively mild conditions using bicarbonate salts and hydrogen peroxide. Further, the inventors have discovered that the bicarbonate ion plays a major role in the decolorization of oxidative dye molecules in keratin fibers. Carbonate salts which are not comprised of a blend of bicarbonate and carbonate forms, do not provide the same degree of decolorization as is obtained with bicarbonates having the same cation. In those cases where the carbonate salts of commerce are comprised of mixtures of the carbonate and bicarbonate forms, such as ammonium carbonate, the degree of decolorization provided by the use of said salt is proportional to the amount of the bicarbonate form present in the mixture. This previously unknown and unsuspected attribute of bicarbonate ion provides for a relatively safe, natural, non-toxic booster for the removal of dye molecules from keratin fibers. The present invention provides for the removal of dye molecules from keratin fibers under reaction conditions milder than those in which persulfates are used and is especially suitable for use on keratin fibers which have been weakened by prior chemical treatments.

DETAILED DESCRIPTION OF THE INVENTION

The method and compositions of this invention provide a means of removing dyes from keratin fibers under relatively mild conditions. This dye removal is accomplished through the use of bleaching compositions containing hydrogen peroxide and bicarbonate salts. The present invention is especially useful to people who have dyed their hair and wish to return their hair to its original color or for people who wish to have variegated hair coloring.

The coloring of keratin fibers is normally achieved by the use of chemical dyes. There are many different types of dyes used to color keratin fibers. These dyes include, but are not limited to, semi-permanent dyes, direct dyes, oxidative dyes, and reactive dyes. Oxidative dyes are commonly used when permanently coloring human hair. For the purposes of this invention, human hair can be taken as representative of the class of fibers known as keratin fibers. The use of human hair as an example should not limit the scope of applications for the present invention as it is commonly known that animal fibers, such as wool and furs, are considered keratin fibers.

The coloring of hair with oxidative dyes in its simplest form is achieved by a process wherein small compounds known as dye intermediates are caused to react with one another in a process called coupling. This coupling reaction requires initiation my an oxidizing agent such as hydrogen peroxide. When coupling reactions between dye intermediates occurs inside the keratin fiber, a large, colored molecule is formed inside the fiber. The sheer size of this molecule prevents it from being removed from the hair by any process other than chemical reaction. The color imparted to the fiber is then a result of a chemical process initiated by an oxidizing agent such as hydrogen peroxide. Those skilled in the art will recognize that current ammonium hydroxide/hydrogen peroxide bleaching solutions are ineffective for removing dye molecules from keratin fibers. Those skilled in the art will likewise know that, while persulfate boosters do permit removal of dye molecules from hair fibers, these treatments are extremely damaging to the hair fibers. Therefore, the bleaching solutions of the current art do not permit individuals with chemically treated hair who have also dyed their hair to safely return their hair to its original color.

Surprisingly, the inventors have discovered that the use of bicarbonate salts in conjunction with oxidizing agents, such as hydrogen peroxide, will remove oxidative dye molecules not only from the surface of the dyed keratin fibers, but will also remove dye molecules deposited within the cortex of the fiber. Additionally, the higher the concentration of bicarbonate ions present in the bleaching composition, the faster the rate and the greater the degree of dye removal from the hair.

Preferably, compositions useful in the present invention contain a bicarbonate salt or blend of bicarbonate salts yielding a bicarbonate concentration from about 2.0 x 10² mole percent to about 4.0 x 10^"' mole percent of the final bleaching mixture. For the purposes of accuracy it is necessary to express the bicarbonate concentrations here as mole percent. Mole percent represents the number of moles of bicarbonate anion per 100 g of finished formulation. When formulating a product, these mole percent values can be converted to weight percent by simply multiplying the given mole percent by the molecular weight of the pure bicarbonate salt. The actual weight percent of the individual bicarbonate salts used in any given bleaching composition is dependent on the molecular weight of the cation associated with the bicarbonate ion in said salt. For example, sodium bicarbonate has a molecular weight of 84.01. Of that total the molecular weight of the sodium cation is 22.99 and bicarbonate is 61.02. Guanidine bicarbonate has a molecular weight of 120.09 of which the guanidine cation comprises 59.07 and the bicarbonate anion is 61.02. To achieve the same amount of bicarbonate anion (0.09 mole percent for example) in bleaching solutions containing these two materials it would be necessary to add 10.8 wt% guanidine bicarbonate but only 7.6 wt% sodium bicarbonate. Therefore for clarity the bicarbonate ranges given in this description are expressed as mole percent. More preferably the bicarbonate salt or salts of said invention should be present in an amount ranging from about 9.0 x 10^"2 mole percent to about 2.5 x 10^"1 mole percent of the final mixture. For the purposes of the present invention, the term bicarbonate salt is any agent or combination of agents capable of generating bicarbonate anion in solution. Additionally, compositions useful in the present invention preferably contain an amount of hydrogen peroxide, or peroxygen compound capable of generating hydrogen peroxide in solution, sufficient to yield an active oxygen content of from about 0.1 wt% to about 10.0 wt% and more preferably from about 2.5 wt% to about 7.0 wt%. For the purposes of the present invention, active oxygen is defined as the concentration of oxidant which can be readily determined by the standard assay procedures set forth by the Cosmetic, Toiletry, and Fragrance Association, Inc. (CTFA) Methods E29-1 and E30-1 issued in October, 1994. Further, the hydrogen peroxide component of the present invention may also contain stabilizers, thickeners, and such ingredients which, when added to the peroxide solution, impart aesthetic properties without destabilizing hydrogen peroxide.

Preferably, the pH of the compositions of the present invention should be maintained in the range where bicarbonate is the predominant species over carbonate or carbon dioxide. This range is accepted to be the pH range of from about 7.0 to about 10.5. More preferably, a pH within the range of from about 7.5 to about 9.5 should be maintained.

Additionally, the compositions of the present invention may contain various penetration enhancing agents. Examples of common penetration enhancing agents include but are not limited to urea and ammonia. However, the benefit of certain penetration aides may be limited by their ability to convert the highly desirable bicarbonate to its ineffective carbonate form or to carbon dioxide. For example, ammonium hydroxide is routinely added to bleaching compositions of the current art to enhance the action of peroxide on natural melanin pigments. In the present invention, however, the hydroxide ion of ammonium hydroxide readily converts the necessary bicarbonates to their ineffective carbonate form. Therefore, care should be exercised when using penetration enhancers so that an excess of bicarbonate anion is always present in the finished composition. Other ingredients such as stabilizers for inhibiting the decomposition of peroxide, thickening agents and other ingredients which, when added, provide aesthetic qualities to the composition or to the treated hair may also be incorporated into the present invention provided that these materials do not convert the bicarbonate salts to their carbonate form or to carbon dioxide. Examples of such ingredients include, but are not limited to, conditioning agents, gelling agents, and moisture retention aides.

In general, any soluble bicarbonate salt may be used in the present invention including, but not limited to, sodium bicarbonate, guanidine bicarbonate, ammonium bicarbonate, lithium bicarbonate, and potassium bicarbonate. Preferably, salts of known bicarbonate content are used in the compositions of the present invention. But the method of combining carbonate salts with an acidic material can be used to generate bicarbonate in situ with the same end result.

As indicated previously, the degree of dye removal and the rate of the bleaching reaction increase as the concentration of bicarbonate ions in the bleaching composition is increased. Preferably, the bicarbonate salt comprises from about 0.1 to about 30 wt% of the bleaching composition. More preferably, the composition contains from about 2.0 to about 20 wt% of the bicarbonate salt. Additionally, the composition preferably contains from about 0.5 to about 30 wt% of a peroxygen compound (capable of giving an active oxygen titer of from 0.1 wt% to about 10.0 wt% using the CTFA Methods described above). More preferably, the bleaching composition contains from about 8.0 to about 20 wt% of the peroxygen compound. However, the weight percents for the bicarbonates are just general ranges and are dependent on the type of bicarbonate salt used. As stated earlier, the actual weight percent will depend on the amount of a particular bicarbonate needed to achieve the desired mole percents discussed above. Also, the actual amounts used will depend on the color of the dyed hair and the degree of dye removal desired.

Additionally, the present invention may be used to enable an individual to obtain variegated hair colors. Currently, a person who wants variegated hair must section the hair and apply a different coloring or bleaching solution to each section of the hair. This process is very time-consuming, expensive, and until now not subject to being reversed if dyes were used to impart multiple hues to the hair. However, using the compositions of the present invention, an individual would be able to initially dye their hair one color, and then selectively add a bicarbonate/peroxygen composition to different parts of their hair to remove the dye from those parts, thereby creating variegated hair in a process involving fewer steps than the processes currently used by hair-care professionals. This process for obtaining variegated hair is especially useful for individuals who have chemically treated their hair before coloring it. When an individual chemically treats their hair, such as relaxing or straightening it, the chemicals used tend to dull the hair. Conversely, hair dyes tend to add sheen to the hair, thereby countering the dulling effect. The present invention allows an individual with curly hair to consecutively relax their hair, obtain a variegated hair color using dyes and the compositions of the present invention, and retain the added sheen imparted to the hair by the dye treatment.

To remove dyes from other keratin fibers, such as wool and furs, the processes are generally the same as for the removal of dye from human hair. A bicarbonate/peroxygen composition is supplied and either applied to only a portion of the fibers, to remove small areas of color, or to all of the fibers, to remove all of the dyed color. The present invention, therefore, has a wide utility in a variety of different areas, such as the production of keratin based textiles.

This invention is further illustrated by the following examples, which are not to be construed in any way as imposing limitations upon the scope thereof. On the contrary, it is to be clearly understood that resort may be had to various other embodiments, modifications, and equivalents thereof, which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the present invention.

EXAMPLES

Examples 1-12

For Examples 1-12, blonde hair obtained from DeMeo Brothers, Inc. (New York, New York) was used as the substrate. Several tresses of this hair were dyed with each of a number of different shades of oxidative dyes manufactured by Carson Products Company (Savannah, Georgia). These dyes are representative of the oxidative dyes formulations currently available in the cosmetics market. Table 1 sets forth the Sample number for each tress of hair, the dye that was used to treat the tress, and the visual observations for each sample as recorded approximately two days after the hair was dyed.

TABLE 1 Dye Products Used to Prepare Tresses for Evaluation of Bleaching

Compositions

Next, a simple aqueous bicarbonate/peroxygen solution was prepared. This solution contained 15.0 wt% ammonium bicarbonate and 10.9 wt% hydrogen peroxide (35 % active). Individual tresses of dyed hair were attached to the inside wall of a 250 ml beaker so that only the lower half (or approximately the lower half) of each tress was exposed to the bicarbonate/peroxygen solution. After 30 minutes, the tresses were removed from the beaker, rinsed and dried, and a visual observation was recorded for each sample. These observations are set forth in Table 2. It should also be noted that the temperature of the solution in the beaker rose significantly, from about 15-20° C to about 35-40° C during these tests. This temperature rise signals that the destruction of dye molecules by bicarbonate/peroxygen is an exothermic process. No attempt was made to control the temperature of the process during this experiment. TABLE 2

Observations for Dyed Hair Treated with Bleaching Compositions Containing Ammonium Bicarbonate and Hydrogen Peroxide

To compare the bicarbonate/peroxygen solution's effectiveness against that of a known combination of bleaching agents, ammonium hydroxide/peroxygen, a second tress of each dyed sample given in Table 1 was exposed to an aqueous solution containing 4.75 wt% ammonium hydroxide (28% active) and 10.9 wt% hydrogen peroxide (35 % active). As in the earlier experiment, each of the tresses was attached to the inside wall of a 250 ml beaker so that the lower half of each tress was located within the ammonium hydroxide/peroxide solution. After 30 minutes, the tresses were removed from the beaker, rinsed and dried, and a visual observation was recorded for each samples. These observations are set forth in Table 3.

TABLE 3

Observations for Dyed Hair Treated with Bleaching Compositions Containing Ammonium Hydroxide and Hydrogen Peroxide

As can be seen by the results, the bicarbonate/peroxygen solutions removed a substantial amount of the dye from each sample and lightened each tress considerably. Conversely, the known bleaching combination of ammonium hydroxide/peroxide failed to remove any color from the darker shades of dye and only slightly, if at all, lightened the color of tresses treated with lighter shades of dye. The slight activity against lighter shades of dye can be explained by the poor deposition of color obtained initially with these dyes. Poor deposition during dyeing means that the majority of the color imparted to the tress is deposited on the surface of the fiber only. Whereas, normally the color would be deposited deep inside the fiber. Surface deposits of color can also be readily removed by the simple act of shampooing. Therefore, the blend of ammonium hydroxide/peroxygen was no more effective than shampooing in this experiment.

Examples of bicarbonate salts which can be employed in this manner include but are not limited to sodium bicarbonate, potassium bicarbonate, and guanidine bicarbonate. When ammonium bicarbonate and guanidine bicarbonate are the salts of choice, effective color removal from the dyed hair is achieved at concentrations of bicarbonate lower than those of potassium and sodium bicarbonates. It is, however, preferred that the total bicarbonate content of the bleaching composition remain within the range of the mole percents previously determined to provide the desired color removal.

Example 13

In Example 13, bicarbonates were added to a commercial hair-bleaching product using a packet of dry, powdered bicarbonate salt or a mixture of bicarbonate salts. This approach was chosen to illustrate the ability of bicarbonate salts to impart dye removal properties to commercial bleaching products and to show the effectiveness of systems more complex than simple aqueous solutions. As can be seen from the following discussion, the addition of bicarbonates to commercial hair bleaching compositions, which are normally effective only against natural hair pigments, converts these formulations to highly effective dye removers.

Bicarbonate salts were used to replace the High-Lift Booster (Part C) of a commercially-available, hair-bleaching product having the following composition:

Part A — Developer (approximately 80 ml) Water, hydrogen peroxide, polyquaternium-37, mineral oil, PPG-1 trideceth-6, pentasodium pentetate, and phosphoric acid.

Part B — Color Base (approximately 48 ml)

Water, dihydroxyethyl soyamine dioleate, isopropyl alcohol, ethanolamine, oleic acid, propylene glycol, PEG-3 cocamine, sodium dihydroxyethylglyoine, trisodium

HEDTA, sodium sulfite, sodium erythorbate, TEA-cocoyl hydrolyzed collagen, potassium cocoyl hydrolyzed collagen, p-phenylenediamine, 4-chlororesorcinol, m-aminophenol, and

4-nitro-o-phenylenediamine sulfate.

Part C — High-Lift Booster

Ammonium persulfate, potassium persulfate, sodium metasilicate, sodium persulfate, sodium stearate, hydrated silica, hydroxypropyl methylcellulose, EDTA, aluminum distearate, sodium lauryl sulfate, and silica.

The instructions for product use required that the Booster of Part C be dissolved in the Developer of Part A. The Color Base of Part B is then added to the blend of booster and developer and shaken well prior to application to the hair. This same procedure was followed in experiments replacing the High-Lift Booster with bicarbonates. In all tests, the finished mixture was applied to tresses of dyed hair for a total of treatment time of 30 min. Samples of the product prepared according to manufacturers directions were evaluated as controls in this experiment.

Tresses of hair dyed a dark-black color (See Table 1 of Example 1) were exposed to the product prepared according to the manufacturers instructions (with high-lift booster) and to samples of the product in which the Booster had been replaced with 16.0 grams of sodium bicarbonate. The treated tresses showed that noticeably more of the dyed color was removed from the tresses treated with the formulation containing bicarbonate than those treated with the product containing the persulfate booster. In fact, the product containing the High-Lift Booster had very little effect on the color of the dyed hair. Though not directly related to the outcome of the experiment, it was also noted that the use of bicarbonate overcame several other disadvantages of the current product. First, the persulfate booster could only be dissolved in the developer with undesirable, vigorous and extended shaking. Because of the shaking necessary to dissolve the booster, the product foamed profusely. This foaming interfered with the addition of the color base to the developer. Further, the conditioning agent in the developer precipitated when the persulfate booster was added. The mixture containing the persulfate booster also developed a strong irritating odor. The sample containing sodium bicarbonate did not suffer from any of these problems.

This example demonstrates that bicarbonates can be added to an existing hair- bleach composition containing hydrogen peroxide and ammonia in a manner similar to that currently employed with persulfate boosters. However, when using this approach, the bicarbonate salts should be added in an amount sufficient to ensure that all of the bicarbonate is not converted to its carbonate form by the hydroxide present in the product. The presence of residual bicarbonate anion in the final mixture is crucial to achieving adequate removal of dyes from the hair. More preferably the bicarbonate salt or salts of the invention should be present in a large excess of the amount needed to react with all of the hydroxide present in the product.

Examples of bicarbonate salts which can be employed in this manner include but are not limited to sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, lithium bicarbonate, and guanidine bicarbonate. When ammonium bicarbonate and guanidine bicarbonate are the salts of choice, effective color removal from the dyed hair is achieved at concentrations of bicarbonate lower than those of potassium and sodium bicarbonates. It is, however, preferred that the total bicarbonate content of the bleaching composition remain within the range of the mole percents previously determined to provide the desired color removal.

Example 14 In this example, bicarbonate salts were generated in situ by reaction of a carbonate salt with an acid. As a control, sodium carbonate was used to replace the bicarbonate in the compositions of Examples 1 through 13. However, the carbonate based compositions failed to remove color from the dyed hair. The degree of lift obtained was comparable to the control formula which contained only hydrogen peroxide and ammonia (i.e. little or no change in the color of the dyed tresses). However, when a proton donor (succinic acid) in an amount capable of converting the majority of the carbonate to its bicarbonate form was added to the bleaching solution, the degree of dye removal obtained was identical to that observed with the sodium bicarbonate compositions of Example 1 through 13. In a second part of this example, guanidine carbonate was substituted for the sodium bicarbonate in the solutions of Example 1 through 13. Once again, there was little or no change in the color of dyed tresses after this treatment. But when guanidine bicarbonate was generated in solution by the reaction of guanidine carbonate with succinic acid, the acid being present in an amount capable of converting the majority of the carbonate to its bicarbonate form, the color of the dye was effectively removed from the tress. Further, the degree of dye removal in this experiment actually exceeded that which was obtained with sodium bicarbonate.

Any carbonate salt capable of conversion to bicarbonate by the action of a proton donor can be used in this embodiment of the present invention. Any material capable of donating a proton to convert carbonate to bicarbonate can be used in this embodiment of the present invention. Examples of other carbonate salts which can be employed in this manner include but are not limited to sodium carbonate, potassium carbonate, ammonium carbonate, lithium carbonate, and guanidine carbonate. Examples of proton donors which can be employed in this manner include but are not limited to inorganic acids, organic acids, and organic compounds which can act as proton donors within the pH range set forth in earlier portions of this document. It is understood, however, that it is the bicarbonate anion content of the bleaching composition rather than the residual carbonate or carbon dioxide which governs the ability of the final oxidizing mixture to remove dyes from keratin fibers.

Claims

CLAIMS We claim:

1. A composition for removing dye from keratin fiber, said composition comprising an aqueous solution of an oxidizing agent admixed with an effective amount of a bicarbonate salt.

2. The composition of Claim 1, wherein the composition is capable of removing the dye from hair fibers.

3. The composition of Claim 1, wherein the dye is selected from a semipermanent, direct dye or an oxidative, reactive dye.

4. The composition of Claim 1, wherein the oxidizing agent is selected from hydrogen peroxide or a peroxygen compound capable of generating hydrogen peroxide in solution.

5. The composition of Claim 4, wherein the oxidizing agent is hydrogen peroxide.

6. The composition of Claim 1, wherein the bicarbonate salt is selected from sodium bicarbonate, guanidine bicarbonate, ammonium bicarbonate, lithium bicarbonate, or potassium bicarbonate.

7. The composition of Claim 1, wherein the aqueous solution further comprises a compound selected from a stabilizer or a thickener.

8. The composition of Claim 1, wherein the aqueous solution further comprises a penetration enhancing agent selected from urea or ammonia.

9. The composition of Claim 1, wherein the aqueous solution further comprises a compound selected from a stabilizer, a thickening agent, a conditioning agent, a gelling agent, or a moisture retention aid.

10. The composition of Claim 1, wherein the composition has a pH of from about 7.0 to about 10.5.

11. The composition of Claim 1, wherein the composition has a pH of from about 7.5 to about 9.5.

12. The composition of Claim 1, wherein the bicarbonate salt comprises from about 9.0 x 10^"2 mole percent to about 2.5 x 10^"1 mole percent of the admixture.

13. The composition of Claim 1, wherein the bicarbonate salt comprises from about 0.1 to about 30 wt% of the composition.

14. The composition of Claim 1, wherein the oxidizing agent comprises from about 0.1 to about 30 wt% of the composition.

15. A method of removing dye from a keratin fiber comprising: applying an effective amount of a dye-removal composition to at least a portion of the keratin fiber; and leaving the solution on the keratin fiber for a preselected period of time to remove at least some of the dye from the keratin fiber; wherein the dye-removal composition comprises an aqueous solution of an oxidizing agent admixed with an effective amount of a bicarbonate salt.

16. The method of Claim 15, wherein the dye is selected from a semipermanent, direct dye or an oxidative, reactive dye.

17. The method of Claim 15, wherein the keratin fiber is selected from wool, fur, or human hair.

18. The method of Claim 15, wherein the oxidizing agent is selected from hydrogen peroxide or a peroxygen compound capable of generating hydrogen peroxide in solution.

19. The method of Claim 15, wherein the bicarbonate salt is selected from sodium bicarbonate, guanidine bicarbonate, ammonium bicarbonate, lithium bicarbonate, or potassium bicarbonate.

20. The method of Claim 15, wherein the aqueous solution further comprises a compound selected from urea, ammonia, a stabilizer, a thickening agent, a conditioner, a gelling agent, or a moisture retention aid.

21. The method of Claim 15, wherein the composition has a pH of from about 7.0 to about 10.5.

22. The method of Claim 15, wherein the bicarbonate salt comprises from about 9.0 x 10^"2 mole percent to about 2.5 x 10^"1 mole percent of the admixture.

23. The method of Claim 15, wherein the bicarbonate salt comprises from about 0.1 to about 30 wt% of the composition.

24. The method of Claim 15, wherein the oxidizing agent comprises from about 0.1 to about 30 wt% of the solution.

25. A method for generating variegated hair comprising; applying a dye solution to the hair to color the hair a substantially uniform color; and selectively applying a dye-removal composition to portions of the hair to selectively remove the dye, thereby generating variegated hair.

26. The method of Claim 25, wherein the dye-removal composition comprises an aqueous solution of an oxidizing agent admixed with an effective amount of a bicarbonate salt.

27. The method of Claim 25, wherein the oxidizing agent is selected from hydrogen peroxide or a peroxygen compound capable of generating hydrogen peroxide in solution.

28. The method of Claim 25, wherein the bicarbonate salt is selected from sodium bicarbonate, guanidine bicarbonate, ammonium bicarbonate, lithium bicarbonate, or potassium bicarbonate.

29. The method of Claim 25, wherein the composition has a pH of from about

7.0 to about 10.5.

30. The method of Claim 25, wherein the bicarbonate salt comprises from about 9.0 x 10^"2 mole percent to about 2.5 x 10^"1 mole percent of the solution.

31. The method of Claim 25, wherein the bicarbonate salt comprises from about 0.1 to about 30 wt% of the composition.