Hair Treatment

Acidic two-bath type composition for permanent waving of hair and for treatment of hair and scalp

Hair Treatment Abstract
An acidic two-bath type composition for the permanent waving of the human hair as well as for the treatment of the human hair and scalp, which consists of an aqueous reducing agent solution (the first bath) containing 3 to 10% by weight of at least one mercaptan acid such as, for example, thioglycolic acid or thiolactic acid and an aqueous oxidizing agent solution (the second bath) containing 1 to 10% by weight of sodium bromate, potassium bromate, or hydrogen peroxide, said reducing agent solution having a pH adjusted with a base to a value 0.1 to 2.0 lower than the isoelectric point of the hair or scalp and said oxidizing agent solution having a pH adjusted with an acid to a value 0.1 to 2.0 lower than the pH of said reducing agent solution but not more than 3.0 lower than the said isoelectric point. Although this composition can be used in a customary manner, it is preferable to apply the oxidizing agent solution having an initial pH 0.1 to 2.0 lower than the pH of said reducing agent solution but not more than 3.0 lower than the isoelectric point, and then, during the application, further adjusting the pH to a value lower than the initial pH. This composition is suitable for imparting a permanent wave to the human hair and for treating the human scalp and hair to enhance the physiological activity of the scalp and hair. The permanent wave of the hair treated with this acidic two-bath type composition is very stable and the scalp and hair treated with the composition is markedly improved in physiological activity.

Hair Treatment Claims
What is claimed is:

1. A process for treating human hair and scalp, which comprises applying to the hair and scalp an aqueous reducing agent solution containing 3 to 10% by weight of at least one mercaptan acid and having a pH adjusted with a base to a value 0.1 to 2.0 lower than the isoelectric point of the hair or scalp; allowing the thus treated hair and scalp to stand for a period of 10 to 30 minutes while substantially protecting the hair and scalp from air, applying to the thus treated hair and scalp an aqueous oxidizing agent solution (A) containing 0.5 to 3 percent by weight of sodium bromate, potassium bromate, or hydrogen peroxide and having a pH 0.1 to 1.5 lower than the pH of the reducing agent solution but not more than 3.0 lower than the isoelectric point of the hair or scalp for 10 to 15 minutes; and then applying to the hair and scalp an aqueous oxidizing agent solution (B) containing 1 to 5 percent by weight of sodium bromate, potassium bromate or hydrogen peroxide and having a pH 0.1 to 2.0 lower than the pH of the aqueous oxidizing agent solution (A) but not more than 3.0 lower than the isoelectric point of the hair or scalp for a period of 10 to 30 minutes, thereafter wash said hair and scalp with water and drying.

2. The process of claim 1, wherein immediately after the application of said aqueous reducing agent solution, the treated hair is wound on curling rods, and then treated with said aqueous oxidizing agent solutions (A) and (B), after which the curling rods are removed to impart permanent wave to the hair.

3. The process of claim 1, wherein the temperature of said aqueous reducing agent solution is 20.degree. to 40.degree. C. and the temperature of the aqueous oxidizing agent solutions (A) and (B) is 20.degree. to 40.degree. C.

4. The process of claim 1, wherein the total quantity of said aqueous oxidizing agent solutions (A) and (B) applied to said hair and scalp is two to three times the quantity of said aqueous reducing agent solution which has been applied to said hair and scalp.

5. The process of claim 1, wherein said oxidizing agent solution A has a pH 0.3 to 0.5 lower than the pH of said reducing agent solution and said oxidizing agent solution B has a pH of 0.3 to 0.5 lower than the pH of said oxidizing agent solution A.

Hair Treatment Description
This invention relates to an acidic two-bath type composition for the permanent waving of human hair and for the treatment of human hair and scalp and, more particularly, to an acidic two-bath type composition for the permanent waving of human hair and for the treatment of human hair and scalp consisting of an acidic aqueous reducing agent solution (the first bath) and an acidic aqueous oxidizing agent solution (the second bath).

The present inventor disclosed in French Pat. No. 1,537,672 and Japanese Patent Publication No. 44,862/73 a three-bath type composition for the permanent waving of human hair comprising an acidic aqueous reducing agent solution, an acidic aqueous oxidizing agent solution, and an alkaline aqueous solution. The inventor's further investigations revealed surprisingly and unexpectedly that the treatment with the alkaline aqueous solution (the third bath) of said three-bath type composition is rather harmful to the human hair and scalp for the following reason: The human hair and scalp treated with the acidic reducing agent solution and the acidic oxidizing agent solution are in an acidic state, the pH being 1.5 to 2.0 lower than the isoelectric point of the human hair and scalp, and hence, are physiologically active. When the hair and scalp in said state are treated with the alkaline third bath, the pH of the solution contacting the hair and scalp, in some cases, becomes substantially equal to the isoelectric point of the hair and scalp, causing coagulation of the protein which results in extreme diseccation of the hair and scalp. It has also been found that the hair becomes too stiff to be combed and the scalp becomes extremely dandruffy. In most cases, the pH of the third bath is on the alkaline side beyond the isoelectric point of the hair and scalp, causing swelling of the hair and scalp, and results in a decrease in strength and suppleness of the hair.

The present inventor has found surprisingly that when the human hair and scalp are treated with an acidic reducing agent bath followed by treatment with an acidic oxidizing agent bath without the subsequent treatment with the alkaline bath, the imparted permanent wave is more stable, the physiological activity of the scalp is more enhanced, and the hair is more improved in suppleness, strength, and resilience than when the subsequent treatment with the third alkaline bath is carried out.

On continued investigations, it has further been found that in a customary acid process for the permanent waving, when the hair and scalp are repeatedly treated with a second bath, i.e., an acidic aqueous oxidizing agent solution, while circulating the bath, the pH of the bath is shifted toward the alkaline side with the lapse of time owing to contamination with various waste matters from the scalp; for instance, the initial pH of 4.0 of the aqueous oxidizing agent solution increased to 4.2 to 4.8 after 2 or 3 minutes and to 5.5 to 6.0 after 5 to 10 minutes, approximating to the isoelectric point of protein (the isoelectric point being dependent on the human race, sex, and age). As is well known, an aqueous oxidizing agent solution in this range of pH is unable to exhibit its oxidizing effect in treating human hair or scalp, while the protein tends to coagulate or become physiologically least active at a pH corresponding to the isoelectric point. It has been thus found necessary to control the pH of the second bath, throughout the course of treating the hair or scalp, so as not to become greater than the pH of the reducing agent bath (the first bath).

The present inventor has further found that more favorable results are obtained when the pH of the reducing bath is 0.1 to 2.0 lower than the isoelectric point of protein, and the pH of the oxidizing agent bath is always lower than the pH of the reducing agent bath during the treatment with the oxidizing agent bath.

An object of this invention is to provide an acidic composition for the permanent waving of human hair, which will not cause coagulation of the protein.

Another object of this invention is to provide an acidic two-bath type composition for the permanent waving of human hair.

A further object of this invention is to provide an acidic two-bath type composition for the treatment of human hair and scalp to increase the physiological activity thereof for the purpose of controlling beauty and health.

A still further object of this invention is to provide a method for the treatment of the human hair and scalp for the purpose of imparting a stable permanent wave to the hair.

Other objects and advantages of this invention will become apparent from the following description.

According to this invention, there is provided an acidic two-bath type composition for the permanent waving of human hair as well as for the treatment of the human hair and scalp, which consists of an aqueous reducing agent solution (the first bath) containing 3 to 10% by weight of at least one mercaptan acid and an aqueous oxidizing agent solution (the second bath) containing 1 to 10% by weight of potassium bromate, sodium bromate, or hydrogen peroxide, said reducing agent solution having a pH adjusted with a base to a value 0.1 to 2.0 lower, preferably 0.1 to 1.0 lower, than the isoelectric point of the human hair or scalp, and said oxidizing agent solution having a pH adjusted with an acid to a value 0.1 to 2.0 lower than the pH of said reducing agent solution but not more than 3.0 lower than the said isoelectric point.

The mercaptan acid used as the reducing agent in accordance with this invention includes, for example, thioglycolic acid, thiolactic acid, and the like. These mercaptan acids may be used alone or in combination of two or more. The reducing agent is dissolved in a suitable amount of water so that the concentration may be in the range from 3 to 10% by weight. Within the said range, the concentration is properly adjusted according to the state of the hair and/or scalp. The pH of the aqueous reducing agent solution thus obtained is adjusted to a value 0.1 to 2.0 lower, preferably less than 1.0 lower, more preferably 0.1 to 0.5 lower, than the isoelectric point of the hair by the addition of at least one base selected from the group consisting of inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and the like; amino-alcohols such as monoethanolamine, triethanolamine and the like; and ammonia. The reducing agent solution is used at 20.degree. to 40.degree. C. Some hair is treated with a lower concentration of the reducing agent solution, and in this case, it is sometime difficult to impart permanent wave to the hair. In such a case, the treatment is effected at higher temperatures to enable the permanent waving.

The isoelectric point of the human hair is in the neighborhood of 5.0, generally in the range from 4.5 to 6.0 depending on the human race, age, and sex. Accordingly, if the isoelectric point is 5.0, the pH of an aqueous reducing agent solution is adjusted to a value within the range from 4.9 to 3.0 depending upon the state of hair and/or scalp. If the pH of the reducing agent bath is below the lower limit of the said range, the activity of the oxidizing agent bath will not sufficiently be manifested. To the aqueous reducing agent solution thus prepared may be added, if necessary, any of the usual auxiliary agents such as glycerol; a nonionic surface active agent, for example, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl ether or the like; liquid paraffin or lanolin. An antioxidant such as thiourea can also be added to keep the reducing agent bath from degeneration in activity and also to keep the pH from change. The amount of the auxiliary agent to be added is similar to that in a conventional system, that is, 5 to 15% by weight for the glycerol and 0.01 to 0.3% by weight for the nonionic surface active agent.

The oxidizing agents used in accordance with this invention are sodium bromate, potassium bromate, and hydrogen peroxide. These are used alone or in admixture of two or more. Although the concentration of an oxidizing agent in the aqueous solution is variable depending on pH, it is generally 1 to 10%, desirable 1 to 5%, more desirably 2 to 3%, by weight. If the pH is lower, the concentration is preferably lower within the said range. A higher concentration is usually preferred for the permanent waving of the hair of Europeans. The pH of the aqueous oxidizing agent solution is adjusted to a value 0.1 to 2.0 lower than the pH of the reducing agent solution by use of an organic acid such as citric acid, tartaric acid, succinic acid, oxalic acid or the like; an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid or the like; or a mixture of two or more of these acids. If any case, care must be taken so as not to allow the pH of the oxidizing solution to become more than 3.0, preferably more than 1.5, lower than the isoelectric point. The adjustment of the pH within the said range is necessary for the enhancement of oxidizing activity of the oxidizing agent bath and for the effective elimination of waste matter from skin. Moreover, the said pH adjustment is also necessary for fixing and stabilizing the curls of hair treated with the reducing agent solution without impairing the hair and rather for increasing the strength of the hair. The oxidizing agent solution, the pH of which has been changed during the treatment, is adjusted to the desired pH with the above-mentioned acid or its aqueous solution for preparing the oxidizing agent solution. In order to carry out the oxidation and the elimination of waste matter, it is preferable to adjust the initial pH of the aqueous oxidizing agent solution to a value 0.1 to 1.5, preferably 0.3 to 0.5 lower than the pH of the reducing agent solution, and, after the treatment with the oxidizing agent solution has been effected for a suitable period of time (generally 5 to 10 minutes), to adjust again the pH with the above-mentioned acid or its aqueous solution to a value lower than the initial pH and continue the treatment, while restoring the initial concentration of the oxidizing agent by replenishment. Alternatively, the oxidation treatment can be carried out in the following way: the oxidizing agent bath is divided into two aqueous oxidizing agent solutions A and B, the oxidizing agent solution A containing 0.5 to 3% by weight of the oxidizing agent and having a pH adjusted to a value 0.1 to 1.5, preferably 0.3 to 0.5, lower than the pH of the reducing agent bath, provided that the pH of the oxidizing agent solution A is not more than 2.7 lower than the isoelectric point, and the oxidizing agent solution B containing 1 to 5% by weight of the oxidizing agent and having a pH adjusted to a value 0.1 to 2.0, preferably 0.3 to 0.5, lower than the pH of the oxidizing agent solution A, provided that the pH of the oxidizing agent solution B is not more than 3.0 lower than the isoelectric point; the oxidation treatment is first conducted with the oxidizing agent solution A for a period of, for instance, 5 to 10 minutes, and thereafter with the oxidizing agent solution B. In this case, either of the oxidizing agent solutions A and B can be conveniently prepared by proper adjustment of concentration and pH from a stock oxidizing agent preparation with higher concentration within the range in accordance with this invention. As in the case of the conventional system in French Pat. No. 1,537,672, the present aqueous oxidizing agent solution can be incorporated with 0.1 to 0.4% by weight of glutamic acid to enhance the oxidizing activity and, if necessary, with suitable amounts of a hair-nourishment and a mineral ingredient.

By treating human hair with the present two-bath type composition as mentioned above, an excellent permanent wave effect is obtained, and by treating the human scalp with the present composition, the elimination of waste matter from the head skin is effectively achieved. Moreover, a similar treatment of a face and hands results in a promotion or recovery of health of skin and achieves the greatest purpose of makeup.

When the human scalp, or hand or foot skin is treated with the present composition, proteins and the like which are considered to be waste matters present in the body are discharged into the treating solution. The discharge of waste matters is considered to promote the metabolism through the skin and activate the physiological action, whereby the health of skin is increased, that is to say, beauty is maintained, and the health of the whole body is increased. Moreover, when the treatment with the present composition was applied to the hair or scalp of a lead-intoxicative person, lead was detected in the wasted composition. That is to say, the treatment of the skin with the present composition can be considered to become an effective means for discharging a poisonous substance such as lead besides the above mentioned waste proteins through physiological action.

The procedure for treating human hair and scalp with the present composition is as follows:

The first step

The hair is sufficiently impregnated with about 50 to 100 g per person (variable within the range depending upon the quantity of hair and the state of scalp) of the aqueous reducing agent solution (the pH of the solution is adjusted to, for example, 4.5 when the hair or scalp has an isoelectric point of 5.0) at 20.degree. to 40.degree. C. and allowed to stand under a suitable cover to keep the hair substantially from oxidation due to air for about 10 to 30 minutes, usually about 15 minutes. If necessary, it may be allowed to stand for a longer period. When the permanent waving is intended, immediately after the aqueous reducing agent solution has been applied, the hair wetted with the solution is wound on curling rods having a diameter corresponding to the intended wave style and the wound hair is covered and allowed to stand for a suitable period of time as mentioned above.

The second step

After the lapse of the above-mentioned time, there is applied to the hair and scalp a shower of the aqueous oxidizing agent solution having a pH adjusted to a value 0.1 to 2.0 lower, preferably 0.3 to 0.5 lower, than that of the reducing agent solution but not more than 3.0 lower than the isoelectric point (for example, a pH of 4.6 to 2.0), the volume of said oxidizing agent solution being 2-3 times the volume of the reducing agent solution, while circulating the oxidizing agent solution at a temperature of 20.degree. to 40.degree. C. By this treatment the hair and scalp are thoroughly impregnated with the aqueous oxidizing agent solution to replace the aqueous reducing agent solution therewith, and simultaneously eliminate dead cells, waste proteins and other waste matters of hair and scalp which have been released by the treatment with the reducing agent solution in the first step. The oxidation treatment restores the activity of the declined cells.

It is preferable that the aqueous oxidizing agent solution has a pH lower than and as near as possible to the isoelectric point in order to eliminate more effectively the waste matter, whereas it is necessary for the effective oxidation that the pH of the oxidizing agent solution be lower than that of the reducing agent solution. It is preferable, therefore, to carry out the oxidation treatment in the following way: The hair and scalp are treated with the aqueous oxidizing agent solution having an initial pH adjusted to a value 0.1 to 2.0 lower than the pH of the reducing agent solution usually for a period of 10 to 15 minutes. At the end of this period, the pH of the oxidizing agent solution is shifted toward the alkaline side owing to the waste matter including dead cells removed into the solution, and in some cases it becomes higher than the isoelectric point, and hence, the oxidization activity of the solution becomes substantially nil. In this case, the acid or its aqueous solution mentioned above is added to the solution to adjust the pH of the solution to a value lower than the initial pH but not more than 3.0 lower than the isoelectric point, and the concentration of the oxidizing agent is also replenished to 1 to 5% by weight. The oxidation treatment with this refreshed solution is continued for a further about 5 to 30 minutes. When the period of the treatment with the reducing agent bath is longer, the treatment with the oxidizing agent bath can be correspondly prolonged to effect sufficient oxidation.

Alternatively, after the treatment with the reducing agent bath in the first step, the hair and scalp are first treated with 100 to 200 cc of the aforesaid aqueous oxidizing agent solution A (for example, pH is 4.2 and oxidizing agent content is 3% by weight) for a period of about 10 to 15 minutes and subsequently with the aqueous oxidizing agent solution B (for example, pH is 3.7 and oxidizing agent content is 3% by weight) for a period of 10 to 30 minutes. The use of the oxidizing agent solution B having a pH lower than that of the oxidizing agent solution A results in an increase of the oxidizing activity, whereby the oxidation action reaches the interior of the hair and scalp to enable a sufficient oxidation.

After completion of the treatment with the aqueous oxidizing agent solution, the hair and scalp are thoroughly washed with water and dried.

The permanent wave imparted by the process described above is very stable and durable, and the hair thus treated is improved in smoothness, suppleness, luster, and strength and is easily combed. Because of elimination of the horny dead cells from the scalp surface, the declined cells are restored and the physiological activity is increased. Further, the blood is purified and the scarf formation is greatly inhibited, resulting in an increase of skin respiration, and this is the most important for health and beauty care.