Compositions Used in Permanent Alteration of Hair Color

In one aspect the invention relates to an aqueous composition containing a conditioning, softening and penetrating agent for hair undergoing treatment with a color altering formulation.

In another aspect the invention relates to an agent which enhances the dissolution of melanin and promotes penetration of an oxidation dye intermediate into a hair follicle.

In still another aspect the invention relates to an additive for a hair bleaching composition and, in yet another aspect an additive for a permanent hair coloring shampoo composition.

The main coloring component of hair is a dark piqment, melanin, which occurs as granules embedded in the hair cortex. The aim of bleaching is to decolorize selectively the natural pigments or applied pigments in the hair with minimal damage to the hair matrix. When hair is bleached, the color changes to lighter and lighter shades depending upon the amount of melanin granules dissolved and removed from the hair fiber. Hydrogen peroxide is the leading solvent for melanin used in the bleaching process; however, along with melanin removal, the peroxide reacts with keratin to cause loss of tensile properties and damage to the hair. More specifically, bleaching occurs in two steps: (1) initial solubilization of the color granules, and (2) decolorization of the dark brown solubilized pigment. The reaction between melano-protein and hydrogen peroxide is confined mainly to the protein-combined cystene residues which are subsequently converted to combined cysteic acid. The solubilization of the melanin granules is connected with the splittinq of the disulfide bridges in the melano protein and it is likely that the disulfide bridge may be the stabilizing factor in melanin, as it is in keratins.

The bleaching process can be halted at any point or can be permitted to continue to a light blonde or platinum shade. The latter provides a good background for a variety of tints which can be obtained by a subsequent coloring step. Such bleaching and coloring combination is known as a double process coloring and causes hair damage by promoting porosity, brittleness, loss of tensile strength and dryness.

Permanent hair colorants involve the use of oxidation dye intermediates which are colorless substances but which, when mixed with oxidizing agents just prior to use, produce color by a process of oxidative condensation. More specifically, the intermediates, in the presence of an oxidant, couple with another oxidation dye intermediate molecule to form a large fused ring color compound within the hair fiber. Since the fused ring product is too large to penetrate the hair fiber, it is essential that good penetration is achieved by the precursor intermediate. The oxidation dye process engenders many changes in the chemical and cosmetic characteristics of the hair which are undesirable. Specifically, the effect of alkali swelling of the hair fiber leads to loss of tensile strength, flexibility and promotes a porous, dry appearance. Additionally, the oxidation dye intermediates often cause skin sensitivity and reddening. Still further, the color imparted on processed hair is often non-uniform since the preprocessed sections, have higher porosity and absorb the interemediate at a faster rate than virign growth which is more resistant to absorption.

Accordingly, it is an object of this invention to overcome or minimize the above deficiencies by providing an additive which obviates skin sensitization, conditions the hair during processing, aids in the penetration of dye intermediate without undue alkaline swelling of the hair fiber, provides complexing sites on which the colorant can form, minimizes the period of hair exposure to chemical solutions, provides a more uniform distribution of color to processed hair by promoting penetration in portions of new hair growth and preserves the tensile properties of bleached or dyed hair.

These and other objects of the invention will become apparent from the following description and disclosure.

In accordance with the present invention there is provided a N-alkyl pyrrolidone which is incorporated into a permanent hair color altering formulation at a concentration of between about 0.01 to about 12 wt. %, preferably between about 0.5 and about 7.5 wt. % based on total weight of the treating formulation. The alkyl pyrrolidones of the present invention are defined by the structure ##STR1## wherein n is an integer having a value of from 1 to 3, and R is alkyl having from 8 to 22 carbon atoms. Of these, compounds wherein R is octadecyl, dodecyl, hexadecyl, octyl, isooctyl, hydrogenated tallow, coco or dodecyl are preferred. Most preferred of these species is N-dodecyl pyrrolidone employed in a concentration of between about 0.75 and about 5.0 wt. %. The present N-alkyl pyrrolidones are preferably incorporated into the color altering formulation just before use.

As "formulation" is used herein, it is to be understood that this term includes a cream, a gel, an emulsion or a watery liquid or solution.

The present alkyl pyrrolidones can be used individually or in admixtures and can be added to any of the commercial hair bleaching or oxidation dye intermediate formulations or compositions containing an oxidation dye intermediate including a permanent shampoo tint, a permanent hair dye, hair bleach, hair blanch or hair dye removal preparation for home or professional use. Alternatively, such color altering preparations may be made up using the components normally included in preparations currently marketed and the N-alkyl pyrrolidone added to improve properties and minimize hair damage.

Generally, the permanent hair dye formulations of this invention are those employed for changing the color of hair, covering up white hair, shading the hair after lightening or simultaneous bleaching and dyeing or double process blonding to provide color alteration of long color durability.

The permanent dye formulations of this invention conventionally include an oxidation dye intermediate such as an analog or a derivative of a phenylene diamine, an aminophenol, a phenol or naphthol which, upon oxidation couples with itself or another analog or derivative of phenylene diamine to form a large fused ring compound having at least one unsaturated chromophoric bond within the hair fiber. The color developed from the colorless intermediate depends on the substituents or terminal groups of the diamine, for example, such groups as an aromatic amine or phenol, an aromatic nitro group or trace amounts of heavy metal. Other factors which alter the shade of the dyed hair include concentration, alkaninity, base composition and the combination of intermediates involved in the oxidation reaction. The following Table I provides a representative group of dye intermediates, color couplers and modifiers employed to obtain specific hair shades.

Other compounds which act as color modifiers or couplers include m-diamines, m-amino phenols, polyhydroxy phenols, which are also stabilizers and antioxidants, and naphthols. The later are often used as secondary dye intermediates in the formulation. Pyridine derivatives have also been suggested for use as a dye intermediate in place of phenylene diamines. In some cases direct dyes can be added to the formulations to provide color highlights.

The color vehicle for the dye intermediates is employed at a pH usually between about 9 and 11 which can be adjusted with ammonium hydroxide to the desired level of alkalinity. The ammonium hydroxide base is preferred since ammonia assists in swelling the hair fiber and by being easily removed. More specifically, the color vehicle is an aqueous solution of soap or synthetic detergent which provides wetting and penetration of the dye intermediate. Ammonium oleate, alkanol amides and shampoo detergents such as fatty alkyl sulfates, fatty acid polypeptide condensates and oxyethylated fatty alcohols are most commonly employed.

In addition to the dye intermediate and color vehicle, formulations may also include interemediate solubility aids such as propylene glycol, ethyl alcohol or isopropyl alcohol and conditioners such as glycerol, lanolin, oleyl alcohol, cetyl alcohol, etc. and antioxidants such as a sulfite, primarily sodium sulfite or bisulfite, and thioglycolic acid which are usually included to prevent premature oxidation. The addition of the present N-alkyl pyrrolidone to this formulation obviates the need for other conditioners promotes penetration of the intermediate into the hair fiber particularly in the areas of new growth, substantially reduces skin sensitization, promotes hair fiber swelling and results in a more uniform distribution of color while giving the hair a soft, silky, conditioned texture after processing. Although the practical amount of N-alkyl pyrrolidone added to the formulation is within the range of from about 0.1 to about 7.5 wt. % of the total formulation, it is to be understood that larger amounts, up to about 12 wt. % can be employed without deleterious effect, economics being the limiting consideration.

The oxidation dye intermediate formulation is applied to the hair with a oxidation dye developer. The developer is an oxidant mixed with the intermediate formulation just before application and is usually applied in equal parts with the intermediate formulation; although when hydrogen peroxide is used as the developer, between about 1.5 and about 2 parts peroxide per part of intermediate can be used to cause bleaching and coloring in a single application. Creams or aqueous solutions of 5 to 7% hydrogen peroxide or urea peroxide are the primary developers commercially employed. However other developers which have been suqgested include chloroates, persulfates, perborates and sodium dichromate. The present N-alkyl pyrrolidone compounds of this invention can also be added to the developer formultion for more uniform distribution and/or thickening effect as in cream applications.

The above dye components are often formulated into shampoos with oleate soaps or ethoxylated fatty alcohols to prevent drip and run-off.

The hair dye operations may be followed by a final conditioning treatment, a neutralizing rinse or an acid balanced shampoo containing in addition to cationic or amphoteric surfactants, cation-active emollients and quarternary polymers. The present N-alkyl pyrrolidones may also be added to such neutralizing applications for conditioning effect.

Some typical hair dye formulations are illustrated by the following

The same developer solution can be used for each of the above hair dyes. The following formulation is representative of a suitable developer.

If desired lactam can be added to the above developing formulation instead of to the dye formulation or the amount of lactam can be divided between both the dye and developer formulations. The concentration of lactam in dye and developer system can range between about 0.75% and about 7.5% by weight, preferably between about 1% and about 5% by weight.

Bleaching involves a process for partial or complete oxidative degradation of the natural color pigment, i.e. melanin granules mainly present in cortex of hair fiber, or removal of applied dye pigment in or on the hair. As a side reaction, bleaching also attacks the hair cuticle proteins, i.e. the keratin protein, and causes oxidative modifications of both the cuticle and cortex proteins; thus decolorizing dissolved melanin color granules and reducing the cross-linking capacity of cystine by oxidation to cysteic acid.

The most common bleaching agent comprises an aqueous soltuion of hydrogen peroxide of between about 5 to 9% strength in a formulation adjusted to a pH of from about 9 to about 11; although urea peroxide and other hydrogen peroxide creams incorporating a thickening agent such as a fatty alcohol or an alkanolamide can also be used.

The peroxide bleaching agent is employed with an activator which is added just before use, ammonium hydroxide being preferred by most practitioners since the ammonia swells the hair fiber to allow for peroxide penetration and is volatile which permits easy removal. Other activators which have been employed include sodium carbonate and ethanolamines. Bleach accelerators and boosters such as persulfate salts of ammonia, potassium and sodium may be used as well and conditioners e.g. ammonium oleate soap, a lipophilic surfactant, cholesterol and lanolin derivatives, are generally included in the peroxide formulation. Notwithstanding the generous use of such conditioning agents, noticeable drying, splitting and texture loss to the hair occurs. Subsequent reoxidation restores the cystine of most of the cysteine residues formed during reduction to disulfide bonds. Reported recoveries are approximately 90%. Still, the bleaching process causes damage such as tangles, dryness, brittleness, greater porosity, swelling, frizzing, etc.

The present N-alkyl pyrrolidones can be added to these formulations in the above amounts to minimize skin sensitivity, to preserve the tensile properties of the hair and to provide a strong conditioning action by forming a thin film over the hair cuticle which eliminates or minimizes hair dryness and breakage. Also, because of their high penetrating power and hair swelling properties, the present N-alkyl pyrrolidones are capable of diminishing the time hair is exposed to the chemical oxidation process.

Some typical hair bleaching formulations include the following.

Other areas in the cosmetic color alternation of hair where the N-alkyl pyrrolidones of this invention can be applied include hair blanching which employs sulfur dioxide or potassium permanganate followed by sodium thiosulfate to convert hair of mixed grey to snowy white and processes for certain hair dye removal techniques which employ a weak solution of sodium hydrosulfite, sodium thiosulfate or aminoiminomethane sulfinic acid.

The present N-alkyl pyrrolidones can be incorporated into any of the foregoing formulations simply by mixing in the prescribed amount, preferably just before use, at ambient temperature and pressure for a period sufficient to provide uniform distribution.

Having thus generally described the invention, reference is now had to the following examples which illustrate preferred embodiments but which are not to be construed as limiting to the scope of the invention as more broadly set forth above and in the appended claims.

An evaluation of N-dodecyl-2-pyrrolidone, as an additive to a standard type of shampoo tint (Nice n' Easy by Clairol - Shade #118, medium brown) was made as described below.

Shampoo tint formulation A-C having the following compositions were divided into equal parts. The first divided portions A-C were combined and immediately applied to the left side of the hair on the scalp of the subject undergoing testing. The subject had light brown and grey hair of medium texture and quality. To the remaining divided portions A-C, after being combined, 1 wt. % of N-dodecyl-2-pyrrolidone was added. The later combined A-C portion, containing the pyrrolidone, was applied to the hair on the right side of the scalp of said subject.

The lotions on the hair on each side of the scalp were allowed to remain for a period of 30 minutes, after which they were rinsed away with water. The hair was then shampooed and blown dry. The following evaluations comparing the hair on the right and left side of the scalp were made on a scale of 0 to 3 wherein 0 represents no improvement or benefit, 1 represents slight improvement, 2 indicates noticeable improvement and 3 indicates great improvement and benefit.

The above bleaching test was repeated on 5 different subjects having medium texture, unbleached, untinted, and non-permed hair of good condition and varying darker shades and each showed the same results as reported in this example.

Example 1 was repeated on a similar subject, except that N-octadecyl-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics resulting from this test were essentially the same as reported in Example 1.

Example 1 was repeated on a similar subject, except that N-hexadecyl-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this test were essentially the same as reported in Example 1.

Example 1 was repeated on a similar subject, except that N-octyl-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this test were essentially the same as reported in example 1, except that penetration was very slightly less.

Example 1 was repeated on a similar subject, except that N-isoctyl-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this test were essentially the same as those reported in Example 1.

Example 1 was repeated on a similar subject, except that N-hydrogenated tallow-2-pyrrolidone was substituted fOr N-dodecyl-2-pyrrolidone. The characteristics found in this test were essentially the same as those reported in Example 1 except that the hair conditioning properties were even more pronounced.

Example 1 was repeated on a similar subject, except that N-coco-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this test were essentially the same as those reported in Example 1. The substitution of the coco-pyrrolidone affects the cost of the overall composition since this lactam is considerably less expensive than some others in the present group.

Example 1 was repeated on a similar subject, except that only 0.05 wt. % of N-dodecyl-2-pyrrolidone was added to the formulation A-C.

Example 1 was repeated on a similar subject, except that 5.0 wt. % of N-dodecyl-2-pyrrolidone was added to the formulation A-C.

Example 1 was repeated on a similar subject, except that 0.5 wt. % of N-dodecyl-2-pyrrolidone and 0.5 wt. % of N-hexadecyl-2-pyrrolidone in admixture were added to the formulation A-C.

It was noted in Examples 8, 9 and 10 that generally the same benefits as achieved in Example 1 were obtained; although to a greater or slightly lesser extent which is directly related to the increased or decreased amount of the lactam present in the composition.

An evaluation of N-alkyl pyrrolidone additive to a standard type of hair bleach (L'Oreal Super Oreal Blanc) was made as described below.

The hair bleach formulation X-Y containing the following compositions were divided into equal parts of X and Y. The first divided portions of X-Y were combined and immediately applied to the hair on the right side of the scalp of the subject undergoing testing. The subject had medium brown hair of good texture and quality. To the remaining divided X-Y portions, after being combined, 2 wt. % of N-dodecyl-2-pyrrolidone was added. The later mixsture of combined X-Y portions, containing the pyrrolidone, was applied to the hair on the left side of the scalp of said subject.

The combined lotions on each side of the scalp were separately maintained on the hair for the prescribed period, 30 minutes, after which the lotions were rinsed away with water. The hair was blown dry and the following evaluations comparing the hair on the right and left side of the scalp were made on a scale of 0 to 3 as in Example 1.

The above test was repeated on 5 different subjects having fine to course, processed and unprocessed hair of various lighter shades and each showed essentially the same results as set forth in the above evaluation.

Example 11 was repeated on a similar subject, except that N-octadecyl-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this example were essentially the same as those reported in Example 11.

Example 11 was repeated on a similar subject, except that N-hexadecyl-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this example were essentially the same as those reported in Example 11.

Example 11 was repeated on a similar subject, except that N-octyl-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this example were essentially the same as those reported in Example 11.

Example 11 was repeated on a similar subject, except that N-isooctyl-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this example were essentiallY the same as those reported in Example 12.

Example 11 was repeated on a similar subject except that N-hydrogenated tallow-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this example were essentially the same as those reported in Example 11, except that slightly better conditioning was evident.

Example 11 was repeated on a similar subject except that N-coco-2-pyrrolidone was substituted for N-dodecyl-2-pyrrolidone. The characteristics found in this example were essentially the same as those reported in Example 11.

Example 11 was repeated on a similar subject, except that 0.05 wt. % of N-dodecyl-2-pyrrolidone was added to the bleach formulation X-Y. The characteristics found in this test were essentially the same as those reported in Example 11, except that less conditioning effect was achieved due to the lowered amount of lactam.

Example 11 was repeated on a similar subject, except that 5.0 wt. % of N-dodecyl-2-pyrrolidone was added to the bleach formulation X-Y. The characteristics found in this test were essentially the same as those reported in Example 11, exoept that the hair conditioning affect was even more pronounced.

Example 11 was repeated on a similar subject, except that 1 wt. % of N-dodecyl-2-pyrrolidone and 1 wt. % of N-hexadecyl-2-pyrrolidone in admixture was substituted for 2% N-dodecyl-2-pyrrolidone. The characteristics found in this test were essentially the same as those reported in Example 11, except that slightly less conditioning was achieved due to the lower amount of lactam.