NO893263L - METHOD AND PROCEDURES FOR Permanent Hair Change. - Google Patents

Abstract

A cysteine-based preparation for permanently waving the hair contains at least a threefold excess of one or more unbranched alkane diols with a C3 to C6 alkyl chain, referred to the cysteine content. Also described is a process for permanently waving the hair using said preparation.

Description

The present invention relates to an agent for permanent hair shape change, which contains a mixture of cysteine and certain alkanediols, as well as a method for permanent hair shape change using this agent.

For permanent hair shape change, alkalized shape change agents are usually used that contain thioglycolic acid or its salts as keratin-reducing active ingredients. Because of this shape-changing agent, however, allergic skin reactions and hair damage, such as hair breakage, hair discoloration or hair loss, can be induced if used incorrectly.

In recent times, hair shape-changing agents have therefore been proposed which contain cysteine as a keratin-reducing active ingredient and which is an amino acid that occurs in nature (for example as a component of hair keratin).

However, the spread of cysteine-containing shape-changing agents, even though they enable a safer and more gentle hair shape-changing than thioglycolic acid-containing agents, has so far remained small because cysteine-containing shape-changing agents exhibit a number of other disadvantages.

Thus, cysteine has only a weak shape-changing activity as well as a low stability. When cysteine-containing shape changers are applied to the hair, the cysteine is left on

due to the air oxygen quickly oxidized to cystine, which is only sparingly soluble in water. The cystine that is formed during the oxidation deposits itself on the hair and skin in the form of a disturbing, hard-to-remove white coating, whereby the shape-changing result is impaired.

Several attempts have already been made to overcome the above-mentioned problems. Thus, for example, attempts were made to increase the oxidation resistance of cysteine-containing shape change agents as well as the storage stability by using certain cysteine derivatives. In US patent document 4153681, to avoid the disturbing cystine be-

add (that is to say to increase oxidation resistance) the use of certain alkyl esters of cysteine is recommended, while West German specification document 1208450 recommends the use of N-alkanoyl and N-aroylcysteines. According to West German

off. document 2951923 it should be possible to improve the storability of cysteine-containing shape change agents by adding N-carbamoylcysteine to these agents. Moreover, according to Japanese explanatory document 48-711495, it should be possible by adding small amounts of thioglycolic acid as well as certain complex-formers to cysteine-based shape change agents to increase the oxidation resistance of these agents and to avoid the formation of the disturbing hydrogen sulphide smell. Likewise, it is known from US patent document 4322401 to alkaline cysteine-based shape change agents to add certain organic acid anhydrides to avoid the disturbing coating formation on the hair as well as for stabilization.

All proposals that have been made so far to solve

however, the problems encountered with cysteine-based shape change agents have not been satisfactory because the shape change properties of the proposed shape change agents were insufficient.

From the literature, for example from US patent 3433868, it is further known that the curling properties of certain mercaptocarboxylic acid-containing (for example thioglycolic acid-containing) shape change agents can be improved by the addition of certain alkanediols (for example 1,2-propanediol or 1,3-butanediol). However, a use of such alkanediols in cysteine-containing shape change agents is not known from the literature.

It is a task for the present invention to provide a means for permanent hair shape change based on cysteine, which on the one hand has a high storage stability - that is, is insensitive to oxidation and does not form hydrogen sulphide during storage - as well as being free from disturbing coating formation and on the other hand possesses a high shape change activity.

It was now surprisingly found that by adding

one or more unbranched alkanediols with a C^- to Cg-alkyl chain to cysteine-containing hair shape-changing agents, the shape-changing activity of these agents can be increased as well as the formation of hydrogen sulphide during storage as well as the formation of disturbing cystine coatings can be prevented.

The object of the present invention is therefore an agent for permanent hair change based on cysteine, which is characterized by the fact that it contains at least one unbranched alkanediol with a C^- to C^-alkyl chain in at least a threefold excess, based on the amount of cysteine.

As alkanediols, straight-chain dihydroxyalkanes with 3 to 6 carbon atoms in the alkyl chain, such as n-propanediols, n-butanediols, n-pentanediols and n-hexanediols, are suitable, whereby 1,2-propanediol and 1,2-butanediol as well as mixtures of these two compounds are particularly preferred.

The hair shape change agent according to the invention preferably contains the alkanediol in an amount from approx. 20 to 75% by weight.

As a shape-changing, hair keratin-reducing component, the hair shape-changing agent according to the invention contains cysteine, which can also be present in the form of its salts (for example as cysteine hydrochloride monohydrate), in an amount from approx. 2 to 25% by weight, preferably in an amount from approx. 6 to 20% by weight.

The weight ratio between cysteine and alkanediol in the agent according to the invention is at least 1:3, preferably 1:3 to 1:5.

The agent for permanent hair shape change is preferably in the form of an aqueous solution or emulsion and has a pH value of approx. 7 to 10. However, it can also be present in a thickened form on an aqueous basis, especially as a cream. The required alkalinity is thereby adjusted by adding ammonia, organic amines, ammonium

and alkali carbonate or bicarbonate.

Of course, the agent according to the invention for permanent hair shape change can contain all additives that are common and known for such an agent, for example thickeners, such as kaolin, bentonite, fatty acids, higher fatty alcohols, starch, polyacrylic acid and their derivatives, cellulose derivatives, alginates, petroleum jelly or paraffin oil, wetting agents or emulsifiers from the groups of anionic, cationic, amphoteric or non-ionic surfactants, for example fatty alcohol sulfates, fatty alcohol ether sulfates, alkyl sulfonates, alkylbenzene sulfonates, quaternary ammonium salts, alkyl betaines, oxethylated fatty alcohols, oxethylated alkylphenols, fatty acid alkanolamides or oxyethylated fatty acid esters, further clouding agents, such as polyethylene glycol esters, or alcohols, such as ethanol, propanol, isopropanol or glycerol, solubilizers, stabilizers, buffer substances, perfume oils, dyes as well as hair conditioning and h year-care ingredients, such as cationic polymers, chitosan derivatives, lanolin derivatives, cholesterol, pantothenic acid or betaine. The aforementioned components are used in the quantities that are usual for such purposes, for example the wetting agents and emulsifiers in concentrations from approx. 0.2 to 10% by weight, while the thickeners can be contained in this agent in an amount from approx. 1.0 to 25% by weight.

Furthermore, known effect-enhancing substances, such as dipropylene glycol monomethyl ether or 2-pyrrolidone, can also be added to this agent in an amount from approx. 2 to 30% by weight.

The agent for permanent hair shape change according to the present invention is insensitive to oxidation, develops no hydrogen sulphide smell even during long-term storage and shows no disturbing coating formation during use. The agent according to the invention enables a clear increase in the shape-changing effect compared to usual cysteine-based shape-changing agents because an increase in the cysteine content is now possible without disturbing side effects occurring.

This shape-changing agent's good storability can be further increased if the agent is instead packaged in the form of a one-component preparation in the form of a two-component preparation - whereby the first, anhydrous component contains the cysteine and the alkanediol, while the second, anhydrous component contains an alkalizing agent as well as additional additives which are common for permanent shape-changing agents - and the ready-to-use agent is prepared immediately before use by mixing the two components together.

The present invention further relates to a method for permanently changing the shape of hair, where the hair is treated with a shape-changing agent before and/or after it has been brought into the desired shape, rinsed with water, then oxidizing after-treatment, rinsed with water, then

lays the hairstyle and then dries, which is characterized by the above-described cysteine-based shape-changing agent being used for the shape-changing treatment, which contains one, based on the amount of cysteine, radnst;three-fold excess of an alkanediol with a C^- to C^-alkyl chain.

In one embodiment of the method according to the invention, the hair is divided into individual bundles and wound on winders with a diameter of approx. 5 to 13 millimeters. The hair is then treated with the shape-changing agent according to the invention in an amount that is sufficient for the hair shape change, preferably approx. 80 to 120 grams.

In a further embodiment of the method according to the invention, the hair is pre-moistened with part of the shape-changing agent, preferably approx. 40 to 60 grams, divided into individual bundles and wound on winders. The hair is then treated once again with the rest of the shape-changing agent, preferably approx. 40 to 60 grams.

After an impact time that is sufficient for

permanent change of shape of the hair and which, depending on the nature of the hair, the pH value and the shape-changing activity of the shape-changing agent as well as depending on the application temperature, amounts to approx. 5 to 45 minutes (5 to 30 minutes with heat exposure; 20 to 45 minutes without heat exposure), the hair is rinsed with water and then oxidized ("fixed"). The finishing agent is used in an amount from approx. 80 to 100 grams depending on the fullness of the hair.

For the oxidizing post-treatment, any desired post-treatment agent which has hitherto been used for such treatment can be used. Examples of oxidizing agents which can be used in such a finishing agent are sodium and potassium bromate, sodium perborate, urea peroxide and hydrogen peroxide.

The concentration of the oxidizing agent differs depending on the application time (usually about 5 to 15 minutes) and the application temperature. Usually, the oxidizing agent is present in the aqueous finishing agent in a concentration from approx. 0.5 to 10% by weight. The agent for the oxidizing post-treatment can of course contain additional substances, such as wetting agents, weak acids, buffer substances or peroxide stabilizers, and can be present both in the form of an aqueous solution or emulsion and in a thickened form on an aqueous basis, especially as a cream, gel or paste .

The wraps are then removed. If necessary can

the unwound hair is now again post-treated oxidizingly. The hair is then rinsed with water, styled and finally dried.

The following examples shall explain the object of the invention in more detail without limiting it to these.

Examples

Before use, the two components are mixed together. The ready-to-use permanent curling agent has a pH value between 9.1 and 9.3.

The washed and towel-dried hair is wound up on curlers with a diameter of 7 millimeters and then thoroughly moistened with the above permanent curling agent. The hair is then covered with a plastic cap. After an exposure time of 25 minutes at room temperature, the covering is removed, the hair is rinsed with water and then oxidatively treated with 100 grams of a 3% hydrogen peroxide solution. After removing the wraps, the hair is rinsed again with water, applied for water waves and then dried.

An even reshaping is achieved without disturbing cystine deposits on the hair.

Example 2: Cysteine-based permanent curling agent

The shape changer's pH value is 9.1.

The hair is washed with a mild shampoo. The towel-dried hair is then pre-moistened with approximately half of the above-mentioned curling fluid, wound on permanent curling rollers with a diameter of 8 millimeters and then re-moistened with the rest of the permanent curling fluid. The hair is then covered with a plastic film. After an exposure time of 12 minutes at 50°C, the covering is removed, the coiled hair thoroughly rinsed with water and then oxidizingly post-treated with 80 grams of 3 percent hydrogen peroxide solution. After removing the wraps, the hair is rinsed again with water and then styled and dried.

The hair treated in this way has a uniform frizziness, the tresses of which exhibit good elasticity and springing power, and are free of disturbing cystine deposits.

Example 3: Permanent curling agent

The permanent curling agent's pH value is 9.5.

The form change processing takes place in that way

which is described in Example 2.

Comparison experiment

The curling properties of the following 5 permanent curling agents are compared using hair strand tests:

(A) Permanent curling agent according to Example 1

(B) Permanent curling agent according to Example 3

(C) Permanent curling agent according to Example 3, but with

a butanediol content of 10% by weight instead of 45

weight percent

(D) permanent curling agent according to Example 1, but with a content of 5% by weight propanediol instead of 35% by weight

butanediol/propanediol

(E) permanent curling agent according to Example 3, but without butanediol addition

For the permanent curling agents used in Examples (C), (D) and (E), the missing amount of alkanediol was replaced with water.

The hair strand fors increase was performed as follows:

First, the hair strand was wound up on a spiral winder and moistened with the permanent curling agent (A). After an exposure time of 20 minutes at 45°C, the hair was rinsed with water, then fixed with a 2.5 percent hydrogen peroxide solution and rinsed again with water. Then the winder was removed, the hair strand was dried and the length of the hair strand (linear distance between the opposite ends) was measured (measurement (a)).

The strand of hair was then hung for 5 hours in the climate cabinet at 80% relative humidity and then hung for 1 hour in water. The length of the hair strand was then measured again (measurement (b)).

From the values thus obtained, the curling effect was calculated using the following equation:

mit LQ = initial phase length of the hair strand

L = the length of the hair strand after the treatment

= the length of the hair strand in the coiled state

In addition to the curling effect, the condition of the treated hair strand was judged in terms of shine, grip and appearance.

The permanent curling agents (B), (C), (D) and (E) were examined for their curling effect in the manner described for the agent (A), whereby for all comparison trials strands of hair of the same nature (undamaged normal hair with a length of 16 cm and a weight of 0.1 g per hair strand) was used. The diameter of the spiral winding used was 8 millimeters.

The results of these comparison tests are summarized in the following Table 1. (a) Curling effect directly after the shape change treatment (b) Curling effect after five hours' residence time in the climate cabinet as well as after one one-hour water treatment.

As can be seen from Table 1, the agents according to the invention (permanent curling agents (A) and (B)) immediately after the permanent curling treatment have a slightly increased curling intensity compared to an agent not according to the invention, with the same cysteine content (permanent curling agents (C) to (E)).

However, after 5 hours at 80% relative humidity and then hanging the hair strand for one hour in water, the permanent curling agents (A) and (B) have a clearly increased curling intensity compared to the permanent curling agents (C), (D) and (E) ). This means that the agents (A) and (B) according to the invention are significantly better in terms of curling stability (that is, the perm's permanence) compared to permanent curling agents for which the ratio of cysteine to alkanediol is less than 1:3 (permanent curling agents (C ) , (D) and (E) ) .

In addition, it appears that hair treated with the permanent curling agents (D) and (E) is somewhat whitish and ugly as a result of the deposition of cystine. In contrast, with the permanent curling agents (A) and (B) according to the invention, such a phenomenon does not occur, and the hair has a stronger shine. Likewise, the odor problem with the permanent curling agents (A) and (B) is significantly less than with the permanent curling agents (C), (D) and (E).

As regards the grip and feel of the treated hair, it appears that the surface of that with the permanent curling agents

(C), (D) and (E) treated hair is less soft and that the grip of the hair is stiff, while the hair treated with the solutions (A)

and (B) according to the invention feels very soft and smooth.

Claims (10)

1. Means for permanently changing the shape of hair on the basis of cysteine, characterized in that it contains at least one unbranched alkanediol with a C^- to C^-alkyl chain in at least a threefold excess, based on the amount of cysteine. 2. Means according to claim 1, characterized in that the cysteine is contained in an amount from 2 to 25 percent by weight. 3. Agent according to claim 1 or 2, characterized in that the alkanediol is contained in an amount from 20 to 75 percent by weight. 4. Agent according to one of claims 1 to 3, characterized in that the pH value is 7 to 10. 5. Agent according to one of claims 1 to 4, characterized in that the alkanediol is selected from 1,2-propanediol and 1,2-butanediol. 6. Agent according to one of claims 1 to 5, characterized in that the weight ratio of cysteine to alkanediol amounts to 1:3 to 1:5. 7. Agent according to one of claims 1 to 6, characterized in that it exists in the form of a 2-component preparation whose first, anhydrous component contains the cysteine and the alkanediol and whose second aqueous component contains an alkalizing agent as well as further additives which are common for permanent shape change agents. 8. Procedure for permanently changing the shape of hair, in which one treats the hair with a shape-changing agent before and/or after bringing it into the desired shape, rinses with water, then oxidizing after-treatment, rinses with water, then applies a hairstyle and then dries, characterized in that an agent according to one of claims 1 to 7 is used for the shape change treatment. 9. Method according to claim 8, characterized in that the shape-changing agent is allowed to act on the hair for 5 to 45 minutes. 10. Method according to claim 8 or 9, characterized in that the shape change agent is used in an amount from 80 to 120 grams.