Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Permanent waving or straightening
Reexamination Certificate
1999-06-08
2002-06-04
Kumar, Shailendra (Department: 1621)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Permanent waving or straightening
C424S047000, C008S127510, C132S204000, C510S126000, C564S224000
Reexamination Certificate
active
06399051
ABSTRACT:
This application is a 371 of PCT/EP98/04678, filed Jul. 25, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to agents and methods for permanent hair shaping containing as the keratin-reducing active ingredient an N,N-disubstituted mercaptoacetamide, to a method for producing such mercaptoacetamides and to the new mercaptoacetamide N-ethyl-N-2′-hydroxyethylmercaptoacetamide.
2. Prior Art
As is known, the conventional technique for achieving permanent hair shaping consists of two processing steps: In the first step, the cystine disulfide bonds of hair keratin are broken by the action of an agent containing a reducing substance (shaping agent). Then, the hair is shaped as desired. In a second step, the cystine disulfide bonds are reformed by means of a fixing agent, namely an agent containing an oxidizing substance.
As shown by the pioneering work described in German Patents 948 186 and 972 424, the conventional permanent wave reducing agent is thioglycolic acid used, for example, in the form of its ammonium or monoethanolamine salt. Other common reducing substances are inorganic sulfites, 2-mercaptopropionic acid (thiolactic acid), 3-mercaptopropionic acid, certain mercaptocarboxylic esters, cysteine and derivatives of these compounds.
All these agents, however, have a number of drawbacks. Alkaline preparations based on mercaptocarboxylic acids, in spite of adequate efficacy, cause hair damage manifesting itself, for example, by extensive hair breakage. Frequently, these agents also have an undesirable effect on the scalp. Finally, the unpleasant odor of the reducing agents used requires extensive addition of perfume to the products.
Some of said problems can be solved by use of 2-mercaptopropionic acid (thiolactic acid). Compared to the generally used thioglycolic acid, however, thiolactic acid has a weaker shaping effect.
The mercaptocarboxylic esters which permit hair shaping also at low pH values are unsatisfactory in terms of their skin tolerance and sensitization risk. In place of mercaptocarboxylic esters, mercapto acid amides such as thioglycolic acid amide or alkyl-substituted and hydroxyalkyl-substituted amides can be used. Such compounds are known from patents WO-A-91/10421 and EP-A-0 455 457. Like the carboxylic esters, these compounds have a high shaping potential also at low pH values, but in terms of their sensitizing properties are even worse than the esters.
SUMMARY OF THE INVENTION
The purpose of the invention is therefore to provide an agent and a method for permanent hair shaping which both in the acidic and in the alkaline range (pH=4.0 to 9.0) makes it possible to achieve uniform shaping and which has no sensitizing potential.
Surprisingly, we have now found that the said drawbacks can be avoided by use of N,N-disubstituted mercaptoacetamides having the following formula (I) and that these mercaptoacetamides have a higher shaping potential than thiolactic acid.
Hence, the object of the present invention is an agent for the permanent shaping of hair, characterized in that it contains as the keratin-reducing active ingredient a compound having the general formula
or a salt thereof, wherein R
1
and R
2
denote a straight-chain or branched alkyl, monohydroxyalkyl or polyhydroxyalkyl or carboxyalkyl group, each with 1 to 6 carbon atoms.
DETAILED DESCRIPTION OF THE INVENTION
Suitable salts of the mercaptoacetamides of formula (I) are all physiologically tolerated salts, particularly the hydrochloride, sulfate, phosphate, lactate, citrate and acetate.
Preferred are compounds in which R
1
and R
2
independently of each other denote CH
3
, CH
2
CH
3
, CH
2
CH
2
CH
3
, CH(CH
3
)
2
, C(CH
3
)
3
, CH
2
CH(CH
3
)CH
3
, CH(OH)CH
3
, CH
2
OH, CH
2
CH
2
OH, CH
2
CH(OH)CH
3
, CH
2
CH
2
CH
2
OH, CH
2
CH(OH)CH
2
OH, CH(CH
3
)(CH
2
OH), CH(CH
2
OH)
2
or CH
2
COOH.
Particularly preferred are compounds having the formulas
The mercaptoacetamides of formula (I) are present in the ready-for-use hair shaping agent in an amount from 3 to 28 wt % and preferably from 5 to 21 wt %.
In another embodiment of the invention, the mercaptoacetamides of formula (I) can also be used in admixture with other, known thiols, such as thioglycolic acid, thiolactic acid, cysteine, cysteamine and alkyl- or acylcysteamines or sulfites.
The ready-for-use hair shaping agents preferably have a pH of 4.5 to 9.5 a pH, of 6.5 to 8.5 being particularly preferred. Suitable alkalizing and pH-adjusting agents are, in particular, ammonia or sodium hydroxide, but also water-soluble, physiologically tolerated salts of organic and inorganic bases, for example, ammonium hydrogen carbonate.
For marketing purposes, the shaping agents can be packaged as a one-component or a two-component system, the agent possibly being in the form of an aqueous solution or an emulsion or else in thickened, aqueous form, particularly as a cream, gel, foam or paste.
Naturally, the shaping agent can contain all known additives commonly used for such agents, for example, thickeners such as bentonite, fatty acids, starch, polyacrylic acid and derivatives thereof, cellulose derivatives, alginates, vaseline, paraffin oils; wetting agents or emulsifiers from the class of anionic, cationic, amphoteric or nonionic surface-active substances, for example fatty alcohols, fatty alcohol ether sulfates, alkylsulfonates, alkylbenzenesulfonates, quaternary ammonium salts, alkylbetaines, ethoxylated alkylphenols, fatty acid alkanolamides or ethoxylated fatty acid esters; moreover, opacifying agents, such as, for example, polyethylene glycol esters; alcohols, such as, for example, ethanol, propanol, polyols such as, for example, 1,2- or 1,3-propanediol, 1,2-, 1,3- or 1,4-butanediol, 1,2-, 1,3-, 1,4- or 1,5-pentanediol and glycerol; sugars such as, for example, D-glucose; solubilizers, stabilizers, buffers, scented oils, dyes and hair-conditioning and hair-care constituents, such as, for example cationic polymers, lanolin derivatives, cholesterol, pantothenic acid and betaine.
The additive ingredients are used in amounts commonly employed for such purposes. For example the wetting agents and emulsifiers are used at a total concentration of 0.2 to 30 wt %, the alcohols in a total amount of 0.1 to 20 wt %, the opacifying agents, scented oils and dyes in an amount of 0.01 to 1 wt % each, the buffers in a total amount of 0.1 to 10 wt %, sugar, solubilizers, stabilizers and hair-conditioning and hair-care agents in an amount of 0.1 to 5 wt % each, whereas the thickeners and solubilizers can be contained in said agent in a total amount of 0.5 to 20 wt %.
Moreover, for the purpose of enhancing the shaping agent's efficacy, it is possible to add to it swelling agents and penetrants, for example dipropylene glycol monomethyl ether, 2-pyrrolidone or imidazolidin-2-one in an amount of 1 to 30 wt %, and for the purpose of preventing excessively tight hair curling dithio compounds, for example dithioglycolic acid, dithiolactic acid, the disulfides of said compounds or their salts.
By varying the pH, it is possible to provide an agent universally suitable for any hair structure, such an agent optionally being used in conjunction with heat. The agent brings about elastic, lasting and uniform shaping from the root to the tip of the hair without inducing allergic or sensitizing reactions.
Moreover, the present invention relates to a method for permanent hair shaping whereby the hair, before and/or after it was brought into the desired shape, is treated with a shaping agent, rinsed with water, treated with an oxidant, rinsed with water, optionally shaped to a wave using water only and then dried, said method being characterized in that the afore-described agent of the invention is used as the shaping agent.
According to a preferred embodiment of the method of the invention, the hair is first washed with a shampoo and then rinsed with water. The towel-dried hair is then divided into individual strands and wrapped onto a curler with a diameter of 5 to 30 millimeters and preferably 5 to 15 millimeters. The hair is then t
Dannecker Beate
Hanefeld Wolfgang
Lang Guenther
Walther Heiko
Kumar Shailendra
Striker Michael J.
Wella Aktiengesellschaft
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