Toilet – Methods – Hair treatment by application of specific chemical composition
Reexamination Certificate
2001-08-20
2004-08-31
Mruck, Brian P. (Department: 1751)
Toilet
Methods
Hair treatment by application of specific chemical composition
C132S202000, C132S204000, C132S205000, C132S206000, C132S207000
Reexamination Certificate
active
06782895
ABSTRACT:
The present invention relates to compositions and methods for lanthionizing keratin fibers using a combination of at least one hydroxide compound and at least one complexing agent effective for dissociating the at least one hydroxide compound in sufficient quantity to effect lanthionization of the keratin fibers. The at least one complexing agent comprises at least one group chosen from groups of formula (I) as defined below and salts thereof.
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. 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 bonds, the permanent curling and the 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 residues [S[CH
2
CH(NH—)(CO—)]
2
]. Thus, the term “lanthionizing” is used when one skilled in the art refers to the relaxing of keratin fibers by hydroxide ions. “Lanthionizing,” as used herein, refers to the formation of at least one lanthionine residue, which may accomplish, for example, any level of relaxation. “Relaxation” and “relaxing,” as used herein, includes any level of relaxing, for example, from slight relaxing to straightening.
For example, hair fibers may be relaxed or straightened by disrupting the disulfide bonds of the hair fibers with an alkaline reducing agent. The chemical disruption of disulfide bonds with such an 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 neighboring 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 available hydroxide ions. As used herein, “available hydroxide ions” are hydroxide ions which are available for lanthionization. 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 available hydroxide ions. Both of these reaction sequences result in lanthionine residue formation. One reaction sequence comprises at least one bimolecular nucleophilic substitution reaction wherein an available hydroxide ion directly attacks the disulfide linkage of a cystine residue. The result is the formation of lanthionine residues 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 an available 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. See Zviak. The result is the formation of a dehydroalanine residue. The dehydroalanine residue then reacts with either the thiol group of a cysteine residue or the amino group of an alanine residue to form a lanthionine residue or a lysinoalanine residue, respectively. These stable irreversible crosslinks in the treated hair make subsequent chemical re-linking of the polypeptides unnecessary. Thus, the only step that may be required following a straightening process using such hydroxide-containing alkaline agents is the removal of any excess alkaline solution to avoid or minimize damage to the hair protein or skin. If such a step is required, an acidic shampoo may be used to neutralize residual alkali and remove it from the hair and scalp.
Relaxing compositions are generally in the form of gels or emulsions that contain varying proportions of strong bases that are water soluble, such as sodium hydroxide, or compositions that contain slightly soluble metal hydroxides, e.g., calcium hydroxide (Ca(OH)
2
), that are converted in situ to soluble bases, e.g., guanidine hydroxide. Traditionally, the two main technologies used in the hair care industry for generating hydroxide ions to relax keratin fibers are referred to as “lye” (lye=sodium hydroxide) relaxers and “no lye” relaxers. The “lye” relaxers use sodium hydroxide in a concentration generally ranging from 1.5% to 2.5% by weight relative to the total weight of the composition (0.38-0.63 M) depending on the base or carrier used, the condition of the hair fibers, and the desired length of the relaxation process. Sodium hydroxide may be extremely effective in straightening the hair but may result in a reduction in strength of the hair fibers and, in some cases, partial or total loss of hair due to hair fiber breakage. Some manufacturers market lithium and potassium hydroxide relaxers as “no lye” but, while this is technically true, these relaxers still rely on the soluble hydroxides of the inorganic potassium or lithium.
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, create a different set of problems. The insoluble byproduct, CaCO
3
, leaves a white residue or unattractive “whitening” or “ashing” that remains in the hair since divalent metals like calcium have a relatively good affinity to keratin. A decalcifying shampoo is 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 an insoluble or partially soluble metal hydroxide, such as Ca(OH)
2
, but reduces or eliminates the problem of ashing caused by the insoluble byproduct, CaCO
3
.
The present invention provides a method for lanthionizing keratin fibers comprising generating hydroxide ions in a composition, said step of generating comprising combining (i) at least one hydroxide composition comprising at least one hydroxide compound and (ii) at least one an activating composition comprising at least one complexing agent effective for dissociating the at least one hydroxide compound in sufficient quantity to effect lanthionization of the keratin fibers. The composition comprising the generated hydroxide ions may then be applied to keratin fibers for a sufficient period of time to lanthionize the keratin fibers. Lanthionization may be terminated when a desired level of relaxation of the keratin fibers has been reached. As used herein, “at least one” means one or more and thus includes individual components as well as mixtures/combinations. Further, “keratinous fibers” as defined herein may be human keratinous fibers, and may be chosen from, for example, hair.
According to the present invention the at least one complexing agent comprises at least one group chosen from groups of formula (I) and salts thereof. Formula (I) is defined as
wherein:
R
1
is chosen from a carbonyl group and a thiocarbonyl group;
R
2
is chosen from CR groups wherein R is chosen from a direct bo
Cannell David W.
Nguyen Nghi Van
Elhilo Eisa
Finnegan Henderson Farabow Garrett & Dunner LLP
L'Oreal (S.A.)
Mruck Brian P.
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