Toilet – Methods – Hair treatment by application of specific chemical composition
Reexamination Certificate
2000-05-08
2002-04-30
Mancene, Gene (Department: 3732)
Toilet
Methods
Hair treatment by application of specific chemical composition
C132S202000, C132S210000, C424S070210, C424S070510
Reexamination Certificate
active
06378530
ABSTRACT:
TECHNICAL FIELD
This invention relates to the art of permanently waving hair, and more particularly, to new formulations for permanent waving lotions which provide long-lasting, durable permanently waved hair while also eliminating the need for a separate oxidation or neutralization step.
BACKGROUND ART
The permanent waving of hair is a well established and well developed art in which substantial attention has been directed to improve the present level of technology. Although substantial changes have occurred throughout the last decades, various problems continue to plague the industry in spite of numerous attempts to reduce or eliminate these problems.
In order to best understand the present state of the art and the problems existing therein, it is important to reiterate that hair fibers are composed of a unique protein called “keratin” which is distinguished by the fact that it contains a very significant amount of an amino acid (cystine) which contains the element sulfur in addition to the elements nitrogen, oxygen, carbon and hydrogen. In the natural biosynthesis of hair, the element sulfur covalently links intra or inter polypeptide chains (K) through two sulfur atoms (S—S) to give keratin protein (K-S-S-K). Only by chemical action can this covalent linkage be broken.
Since these disulfide bonds are relatively strong bonds and are not affected by water, permanent results are obtained by altering the disulfide bonds through cleavage and recombination. In this way, a permanent configuration change of the hair is attained. However, chemical action is required in order for this disulfide linkage to be broken. In this regard, many prior art compositions have been developed for the cold permanent waving of hair. Typically, these prior art systems treat the hair with reducing agents which break the disulfide (cystine) linkage in the hair, while the hair is wound around a curling rod.
In general, permanent hair waving is usually carried out by subjecting the hair to reagents containing a free—SH group or thiol. These materials are also called mercaptans. In this treatment, the hair usually is either wrapped on the rods with water or the lotion containing the thiol, and then saturated with thiol lotion. The thiol waving agent acts to break the disulfide bonds within the hair fiber forming thiol groups in the hair protein and disulfide bonds between two thiol waving agent molecules. The chemistry involved in the reaction of the mercaptan with the cystine disulfide bonds in the hair fiber is illustrated by the following chemical equations (i), (ii) and (iii):
KSSK+RSH⇄KSH+RSSK (i)
RSSK+RSH⇄KSH+RSSR (ii)
KSSK+2RSH⇄2KSH+RSSR (iii)
When a sufficient number of hair disulfide bonds have been broken, the hair is realigned to pair previously unpaired hair protein thiol groups opposite opposite each other. At this point, the hair is rinsed, removing the unreacted thiol waving agent and any water soluble disulfide reaction product formed from it. Then, the hair is saturated with an oxidizing agent, or neutralizer, such as hydrogen peroxide or bromate salt, to reform disulfide bonds between the newly paired hair protein thiols, thereby giving the hair a new configuration or wave, or adding curl to the hair. By rebonding the sites of the reduced keratin in their new curled configuration, a permanent set which is impervious to water is established.
Much of the rebonding of the reduced sites is accomplished by the action of the chemical oxidizing agent, which is typically hydrogen peroxide, and can be illustrated by the following chemical reaction:
2KSH+H
2
O
2
→KSSK+2H
2
O
The most commonly used reducing agents employed in the permanent deformation of hair keratin are salts and esters of thioglycolic acid. Other less commonly used reducing agents include cysteine, cysteamine, thiolactic acid, their derivatives and mixtures thereof. These reducing agents are very effective in the reduction of disulfide bonds and under certain conditions can reduce more than 50% of the keratin cystine bonds.
Although effective in providing excellent reducing capabilities, the above mercaptans and their corresponding derivatives possess problems that are difficult to control. Typical disadvantages include the irreversible fiber alteration as made evident by increased fiber porosity and decreased tensile properties as well as the emission of malodor.
Much efforts have been expended in attempts to minimize these undesirable attributes. These include pretreatments, barriers which decrease the rate of diffusion, reduction of the mercaptan concentration and/or the pH of the reducing agents, and duration of reduction time. Many of these pretreatments yield other undesirable characteristics such as oily, greasy, and dirty feeling of the hair fiber.
Furthermore, in seeking to attain an improved permanent waving lotion, numerous agents have been employed in combination with the thiol compound to provide improved results. In this regard, much effort has been expended in employing numerous compounds as the alkalizing agent used in combination with the thiol compound to control the pH level as well as to reduce the malodor associated with permanent waving. As is evident from prior art disclosures, such as found in
Handbook of Cosmetic Science,
H. W. Hibbot, Ed, The MacMillan Company, New York, N.Y. 1963, Page 393-394 and
J. Soc. Cosmet. Chem.,
Garcia et al, Volume 41, Page 149 (1990), the use of alkali metal salts has been attempted and has been found to be ineffective. As disclosed in these prior art discussions, alkali metal salts, in general, and sodium hydroxide in particular, has been found to be incapable of providing a satisfactory permanently waved head of hair when combined with a thiol compound.
As a result, the cosmetic industry has sought alternate directions for creating reducing agents which principally have focused on the use of ammonia or ammonium based compounds employed in combination with the thiol compound to produce an effective permanent wave reducing agent. However, in spite of substantial effort to attain a reducing agent which can be employed with substantially less malodor being produced, these attempts have failed to provide a composition which is capable of producing a permanently waved head of hair at least equivalent to conventional reducing lotions having these inherent deficiencies.
Another major drawback that has consistently plagued prior art permanent waving systems is the requirement that a separate oxidizing or neutralizing agent must be employed after the application of the reducing lotion. The application of a separate oxidizing agent requires an additional step, as well as exposing both the beautician and the customer to further chemical exposure.
As a result, additional time is required and further chemical interaction of the hair fibers must be experienced. Although attempts have been made to eliminate the neutralization steps, these attempts have not been successful.
Furthermore, in the art of permanent waving, there is much trial and error, with the hair being over-processed, in some instances. The characteristics of over-processing are raspy feel to the hair or a loss of the natural underlying color. Structural evaluation of the hair fiber by instrumentation usually reveals that the structural integrity of the hair is lessened, which is evidenced by either an increase in the amount of cysteine and cysteic acid or a lessening of the cystine content relative to the hair not so processed. The increase in cysteic acid amount is about 15% to 25% contributed by the neutralization step.
Some detrimental effect to hair fiber is unavoidable, as the process of permanent waving involves controlled bond scission of the disulfide linkages within the keratin proteins. Recovery of these disulfides is the determining factor for the tightness of the curls and overall tensile strength. Typically, in order to reshape hair fibers into a lasting configuration, 20% to 50% of available disulfide bonds mus
Kambe Tetsuya
Rezvani Ahmad
Savaides Andrew
Tasker Rushi
Shiseido Co. Ltd.
Stoltz Melvin I.
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