Drug – bio-affecting and body treating compositions – Bleach for live hair or skin
Reexamination Certificate
2000-03-10
2003-06-03
Travers, Russell (Department: 1619)
Drug, bio-affecting and body treating compositions
Bleach for live hair or skin
C424S060000, C424S062000, C424S063000, C424S070200, C424S070400, C424S070600, C424S613000, C424S616000, C424S615000, C424S693000, C514S731000, C514S728000, C435S028000, C435S189000, C435S192000, C008S401000, C008S406000, C008S416000, C008S421000, C008S649000
Reexamination Certificate
active
06572843
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for dyeing hair that has been subjected to a chemical reduction step, more particularly, to a method for dyeing such hair by means of at least one oxidoreductase and at least one chemical oxidizing agent such as peroxide.
BACKGROUND OF THE INVENTION
Hair setting processes, including both permanent waving and straightening, are usually carried out at room temperature. The process typically includes at least two fundamental steps: i) reducing covalent disulfide linkages in the keratinous fibres of the hair, thereby rendering the hair deformable without elasticity, the hair typically being wetted by a solution containing a reducing agent and either rolled on curlers or mechanically straightened, and ii) rinsing and neutralization of the reducing agent, followed by re-establishment of a network of cross links in the keratinous fibres of the hair, either by air oxidation or by application of a so-called fixer (which usually contains an oxidizing agent), thereby rendering the curly or straightened shape “permanent”.
For the purpose of breaking the disulfide cross links, a number of reducing agents can be used, including strong bases such as sodium hydroxide and guanidinium hydroxide, as well as weaker bases such as thioglycolic acid, thioacetic acid, and other mercamtans. Permanent waving processes typically use substances based on thioglycolate, whereas permanent hair straighteners (also known as “relaxers”) normally require more aggressive reducing chemicals, e.g., hydroxides, in order to achieve “permanent”, straightening.
Among reagents used for the purpose of fixation of hair, i.e., compounds capable of re-establishing the physicomechanical properties of the hair by forming disulfide and other cross links between keratin chains, hydrogen peroxide (H
2
O
2
) is the most commonly used reagent as H
2
O
2
reacts rapidly with the keratin —SH groups. Other examples of commonly used oxidizing agents are perborates, bromates, chlorites, iodates, bromates, persulphates and tetrathionates. These oxidative agents often over-oxidize and damage the hair, producing sulphonic acids such as cysteic acid instead of simply reforming disulfide bridges.
Hydrogen peroxide is also the conventional catalyst in is hair dyeing formulas, and it is important to recognize that peroxide concentrations used for hair dyeing formulas are significantly larger than those used to reform hair cross links in the oxidative, restorative phase of a hair setting treatment (also used at different pH).
It is possible, and not uncommon in home straightening treatments, to use atmospheric oxygen as an oxidizing agent for reformation of hair cross links. The direct use of atmospheric oxygen, however, suffers from the disadvantage that several hours are required in order to complete the reaction. This option is even less appealing when used in conjunction with permanent waving treatments, since hair fixation should occur while the hair is in the desired conformation; i.e., while the hair is on curlers.
Many consumers would like to apply a permanent dye at the same time as a permanent hair straightening (or waving) treatment. Unfortunately, this combination causes severe damage to the hair, primarily because the damage caused by exposure to high levels of H
2
O
2
(i.e., more than 1% H
2
O
2
, such as those used in conventional hair dyes) is exacerbated when hair is in a damaged and vulnerable state as a result of exposure to strong reducing agents. For this reason, consumers are advised to wait at least two weeks between permanent straightening and permanent dyeing of hair. While temporary hair dyes can be applied to hair directly after a straightening treatment, there is a long-standing need and desire for a product that allows simultaneous permanent straightening and permanent dyeing of hair without excessive hair damage.
Permanent hair dyes are durable to sunlight, shampooing, and other hair treatments and are ordinarily refreshed periodically (about once a month) as new hair grows out. With these dyeing systems, the dyes are created directly in and on the hair. Small aromatic colourless dye precursors (e.g., p-phenylenediamine and o-aminophenol) penetrate deep into the hair where the precursors are oxidized by an oxidizing agent into colored polymeric compounds. These colored compounds are larger than the dye precursors and are not easily washed out of the hair.
Traditionally, H
2
O
2
is used in concentrations of about 1-10%, normally from about 3-6%, as the oxidizing agent. The use of H
2
O
2
in dye compositions has some disadvantages as H
2
O
2
damages the hair. Further, conditions frequently used for oxidative dyeing require treatment at high pH (normally around pH 9-10), which also causes damage to the hair.
To overcome the disadvantages of using H
2
O
2
, it has been suggested to use oxidation enzymes to replace H
2
O
2
.
U.S. Pat. No. 3,251,742 (Revlon) describes a method for dyeing human hair by dye formation in situ (i.e., on the hair).
An oxidative enzyme is used for the colour formation reactions at a substantially neutral pH (pH 7-8.5). Laccases, tyrosinases, polyphenolases and catacolases are mentioned as suitable oxidation enzymes.
EP patent No. 504.005 (Perma S. A.) concerns compositions for hair dyeing which do not require the presence of H
2
O
2
(hydrogen peroxide). The compositions comprise an enzyme capable of catalysing the formation of the polymeric dyes and also dye precursors, such as bases and couplers, in a buffer solution wherein the pH of the composition is between 6.5 and 8 and the enzyme has an optimal activity in the same pH range.
A method for enzyme-mediated dyeing of keratinous fibres, such as hair, has been described in WO 97/19999 (Novo Nordisk) and WO 97/19998 (Novo Nordisk).
Canadian patent 67:93913 discloses a composition containing a metal-containing dye for simultaneously permanent waving and dyeing hair. EP patent No. 328816 describes a process for dyeing of waved or relaxed hair using a metal ion-catalyzed hair dyeing composition.
There is still a need for a commercially viable method that allows (i.e., can be performed without significantly damaging the hair) simultaneous permanent setting (straightening or waving) and permanent dyeing of hair, with sufficient depth and permanence of color on hair.
A method that permits simultaneous permanent dyeing and setting of hair will give consumers a new range of options in their hair style choices. In particular, it will increase convenience for consumers, who will no longer have to wait weeks after a permanent setting treating prior to dyeing their hair.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an improved method for permanent dyeing of chemically reduced hair such that the dyeing is suitably permanent, and sufficiently mild such that it does not cause significant damage to hair and can be performed immediately following, or, preferably, during a hair setting treatment. The present invention thus fulfills a long-standing industry need for a method that can provide permanent dyeing on chemically reduced hair without significant damage, thereby allowing a combined permanent setting and dyeing treatment.
It is advantageous to dye the reduced hair as an integrated component of a hair setting treatment not only to provide convenience for the customer, but also because the enzyme-mediated oxi- is dative process is an active and beneficial component in reformation of hair cross links, and dyeing of reduced hair is enhanced (both depth and permanence of color) relative to dyeing of hair in its normal, oxidized state.
The inclusion of small amounts of hydrogen peroxide or functional equivalents enhances dyeing of reduced hair relative to enzyme-mediated dyeing treatments not incorporating H
2
O
2
.
The present invention can be applied as part of a permanent hair waving or straightening process, preferably as part of a straightening process.
The present invention provides a method for treating reduced hair comprising contacting said hair with
McDevitt Jason Patrick
Sorensen Niels Henrik
Lumbris Elias J.
Novozymes A/S
Sharareh Shahnam
Travers Russell
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