Toilet – Methods – Hair treatment by application of specific chemical composition
Reexamination Certificate
2000-11-22
2002-08-20
Manahan, Todd E. (Department: 3732)
Toilet
Methods
Hair treatment by application of specific chemical composition
C424S070400
Reexamination Certificate
active
06435193
ABSTRACT:
The present invention relates to compositions and methods for lanthionizing keratin fibers using a combination of at least one multivalent metal hydroxide and at least one cation exchange composition. The at least one cation exchange composition can dissociate the at least one multivalent metal hydroxide in sufficient quantity to effect lanthionization of the keratin fibers. In one embodiment, the process of lanthionizing keratin fibers results in relaxed or straightened hair.
Straightening or relaxing the curls of very curly hair may increase the manageability and the ease of styling such hair. In today's market, there is an increasing demand for hair care products referred to as “hair relaxers” which can relax or straighten naturally curly or kinky hair. Hair relaxers may either be applied in a hair salon by a professional or in the home by the individual consumer.
Hair fiber is a keratinous material, which is comprised of proteins (polypeptides). Many of the polypeptides in hair fibers are bonded together by disulfide bonds (—S—S—). A disulfide bond may be formed from the reaction of the two sulfhydryl groups (—SH), one on each of two cysteine residues, which results in the formation of a cystine residue. While there may be other types of bonds between the polypeptides in hair fibers, such as ionic salt bonds, the permanent curling and shape of the hair is essentially dependent on the disulfide bonds of cystine residues.
Generally, hair relaxing processes are chemical processes which may alter the aforementioned disulfide bonds between polypeptides in hair fibers and may form lanthionine [S(CH
2
CHNH
2
COOH)
2
]. Thus, the term “lanthionizing” is used when one skilled in the art refers to the relaxing or straightening of keratin fibers by hydroxide ions.
For example, hair fibers may be relaxed or straightened by disrupting the disulfide bonds of the hair fibers with an alkaline agent or with a reducing agent. The chemical disruption of disulfide bonds with an alkaline agent is generally combined with mechanical straightening of the hair, such as combing, and straightening generally occurs due to changes in the relative positions of opposing polypeptide chains within the hair fiber. This reaction is generally terminated by rinsing and/or application of a neutralizing composition.
The reaction with the alkaline agent is normally initiated by hydroxide ions. Not to be limited by theory, there are two reaction sequences that are predominantly used in the art to explain the disruption of the disulfide bonds in hair fibers by hydroxide ions. Both of these reaction sequences result in lanthionine residue formation. One reaction sequence comprises a bimolecular nucleophilic substitution reaction wherein a hydroxide ion directly attacks the disulfide linkage of a cystine residue. The result is the formation of lanthionine and HOS. See Zviak, C.,
The Science of Hair Care,
185-186 (1986). The second reaction sequence comprises at least one &bgr;-elimination reaction initiated by the nucleophilic attack of a hydroxide ion on a hydrogen atom bonded to a carbon atom that is in the &bgr;-position with respect to the disulfide bond of a cystine residue. Id. The result is the formation of a dehydroalanine residue. The dehydroalanine residue then reacts with either the thio group of a cysteine residue or the amino group of an alanine residue to form lanthionine or lysinoalanine, respectively. Regardless of the reaction mechanism, hair relaxing processes proceed via the release of hydroxide ions that can penetrate the hair fiber and which may transform cystine residues to lanthionine residues.
Most frequently, relaxing compositions are in the form of gels or emulsions that contain varying proportions of strong water-soluble bases, such as sodium hydroxide (NaOH), or of compositions that contain slightly-soluble metal hydroxides, such as calcium hydroxide (Ca(OH)
2
), which can be converted in situ to soluble bases, such as guanidine hydroxide. Traditionally, the two main hair relaxing technologies used in the hair care industry for generating hydroxide ions are referred to as “lye” relaxers (lye=sodium hydroxide) and “no lye” relaxers. The “lye” relaxers generally comprise sodium hydroxide in a concentration generally ranging from 1.5% to 2.5% (0.38M-0.63 M) depending on the carrier used, the condition of the hair fibers, and the desired length of the relaxation process. Sodium hydroxide may be extremely effective in straightening hair fibers but may result in a decrease in the strength of the hair fibers and, in some cases, partial or total loss of hair due to hair fiber breakage.
While “no lye” relaxers may not contain lye, they may nonetheless rely on the soluble hydroxides of inorganic metals, such as potassium hydroxide and lithium hydroxide. Other “no lye” relaxers may use hydroxide ions obtained, for example, from a slightly-soluble source, such as Ca(OH)
2
. For example, the slightly soluble Ca(OH)
2
may be mixed with guanidine carbonate to form guanidine hydroxide, a soluble but unstable source of hydroxide, and insoluble calcium carbonate (CaCO
3
). This reaction is driven to completion by the precipitation of CaCO
3
and is, in effect, substituting one insoluble calcium salt for a slightly soluble calcium salt. Because guanidine hydroxide is unstable, the components are stored separately until the time of their use.
Guanidine carbonate and calcium hydroxide, however, may create a different set of problems. The insoluble byproduct, CaCO
3
, can leave a white residue or unattractive “whitening” or “ashing.” This residue remains in the hair since divalent metals such as calcium have a relatively good affinity for keratin. A decalcifying shampoo may be subsequently needed to remove the ashing.
Thus, there is still a need for a process to relax keratin fibers that has the advantages of using a slightly-soluble metal hydroxide, such as Ca(OH)
2
, but which reduces or eliminates the problem of ashing caused by insoluble byproducts, such as CaCO
3
.
To achieve at least one of these and other advantages, and in accordance with the purpose of the invention as embodied and broadly described herein, the present invention, in one aspect, provides a composition for lanthionizing keratin fibers comprising at least one multivalent metal hydroxide and at least one cation exchange composition. According to the present invention, at least one cation exchange composition may be chosen from silicates. The at least one multivalent metal hydroxide may be chosen from, for example, calcium hydroxide, barium hydroxide, magnesium hydroxide, aluminum hydroxide, cupric hydroxide, strontium hydroxide, molybdenum hydroxide, manganese hydroxide, zinc hydroxide, and cobalt hydroxide.
The present invention is also directed to a method for lanthionizing keratin fibers to achieve relaxation of the keratin fibers by generating hydroxide ions in an ionizing solvent comprising combining at least one multivalent metal hydroxide and at least one activating composition, wherein the at least one activating composition comprises at least one cation exchange composition, to generate hydroxide ions; and applying a composition comprising the generated hydroxide ions to keratin fibers for a sufficient period of time to lanthionize the keratin fibers. Lanthionization is terminated when the desired level of relaxation of the keratin fibers has been reached. The at least one multivalent metal hydroxide may be added to a composition comprising the at least one cation exchange composition or vice versa.
The invention also provides for a multicomponent kit for lanthionizing keratin fibers, wherein the kit comprises at least two separate compartments. One compartment of the kit comprises a composition for generating hydroxide ions that comprises at least one multivalent metal hydroxide while the other compartment of the kit comprises at least one activating composition comprising at least one cation exchange composition for generating hydroxide ions.
It is to be understood that both the foregoing general descr
Cannell David W.
Nguyen Nghi Van
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
L'Oreal (S.A.)
Manahan Todd #E.
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