Throughout the years, there has been a desire to alter the color of synthetic and natural fibers. In particular, coloring of human hair has been sought in view of changing styles and fashion. However, due to the inherent composition of hair fiber, and the chemical and mechanical exposure encountered by the hair fibers during normal care and styling, obtaining and maintaining a precise color has been an illusive goal.
As is well known, hair is composed of a unique protein material called “keratin” which is repeatedly being subjected to both chemical and mechanical damage from combing and brushing, as well as from sunlight, chlorinated water, shampooing, permanent waving, and other such treatments involving various chemicals. As a result, depending upon the length of the hair fibre, the distal ends of each hair fiber tend to have substantially more damage than the proximal ends nearer to the scalp. This inconsistency causes variation in the dye uptake by the hair fiber, resulting in color variations along the length of the hair fiber.
In spite of the long history with the coloration of hair and the extensive effort that has been expended in attempting to eliminate the problems associated with the dyeing of human hair, no system has been achieved which is capable of overcoming all of the drawbacks and difficulties encountered with hair dyes. Included among these drawbacks is the need for a dye system which avoids any adverse effect on the skin or hair of the user.
Other problems which continue to plague conventional prior art dyes are the longevity or wearability of the resulting color, its ability to resist fading, and its ability to resist changes due to washing, combing, or rubbing. Furthermore, the accuracy of the color imparted to the hair fiber during the dyeing process, as well as the ease with which the hair fiber is capable of being dyes, are also important factors which prior art dye compositions have been incapable of successfully overcoming.
In general, prior art hair coloring and fiber coloring mixtures comprise dyestuffs obtained from coal tar derivatives or from synthetic routes. These mixtures are typically formulated to provide a particularly desired wearability of the color on the fiber. Dyes formulated for coloring hair fibers, are typically termed temporary, semi-permanent, or permanent.
Temporary dyes or hair colors last through a few shampooings, while semi-permanent hair colors are retained for three to six weeks of shampooings. The permanent dyes or colors, which are often equally employable on plant derived and synthetic fibers, as well as hair keratin, cannot be shampooed out from hair fibers.
It is well known that many standard colors employed on hair or on synthetic fibers cause irritation due to the sensitivity of many individuals to these dyes. As a result, in the case of human application where hair is being dyed, a pre-application is required. In this pre-application, a small amount of color mixture is applied to the skin of the individual and allowed to remain thereon for a period of twenty-four hours, prior to use, in order to assure that an adverse reaction will not occur. If an adverse reaction is found, the dye formulation cannot be used.
It has also been found that repeated contact of the human skin to many prior art dye formulations derived from coal tars and synthetic routes often results in discomfort to the individual receiving the dye application. In addition, various other disadvantages are often encountered with the use and application of standard dyes and their application procedures.
Non-permanent dye formulations are principally employed in the coloring of human hair. Furthermore, most compositions used for temporarily tinting hair fibers contain acid dyes.
The nature of these non-permanent dyestuffs is to coat the fiber where the dyestuff remains on the surface of the fiber, due principally through weak electrostatic interaction. As a result, any mild mechanical stress, such as is caused by rubbing or combing the hair, causes much of the dyestuff to be removed. Furthermore, shampooing or immersion of the hair into water for any protracted time period results in a complete removal of the dyestuff and, hence, the temporary nature of the resulting color.
Semi-permanent hair coloring compositions typically comprise mixtures of one or several dyestuffs in a solution containing alcohol and water. Often the hair coloring is employed in a foam base which allows the product to be applied in various “shampoo-in” applications.
The amount of color deposited on the hair by such applications is subject to substantial variations, although the actual color deposited is typically low. In addition, grey hair is the most difficult to color in this way and loses the applied color most rapidly upon shampooing. As a result, repeated re-applications are necessary.
If an individual does not regularly have the color reapplied, the hair fibers will develop an uneven hair color, due to an uneven distribution of the dye along the hair fibers. This produces an unnatural appearance and cast to the hair. Furthermore, the repeated use required by such product causes the excess dyestuff rinsed from the hair to enter the waterways, thereby adding to the cumulative problems presently being realized in the contamination of ground water.
In view of the difficulties and drawbacks detailed above in regard to semi-permanent hair colors and temporary hair colors, individuals wishing to dye their hair have sought the use of permanent dye formulations. In particular, professional hair stylists prefer the use of permanent dye formulations, since they wish to provide their customers with more durable and longer lasting results.
In using virtually all prior art permanent hair dyes, hydrogen peroxide is required along with the particular dyestuffs. During the application, the mixture enters into the hair fibers and reacts therein to form larger dyes of a predetermined color. Since the dy molecules formed are larger than the molecules entering the hair fibers, the formed dyes are trapped within the hair fibers, and are unable to diffuse out of the fibers. Consequently, the resulting coloring is trapped within the hair fiber and is permanent.
One advantage that has been found from using these types of dye mixtures is the ability to lighten hair, since the presence of both hydrogen peroxide and the alkaline environment of the mixture will also remove natural hair color, which is then replaced by the colors formed in situ. Unfortunately, many of the dye precursors used in the formation of permanent hair colors are known to be sensitive to many individuals and, in some cases, have purported to be active in biological systems in causing interference with different aspects of cellular action.
In addition, another principal concern that has existed in the prior art is that the typical processes used to color hair involve contacting the hair with a mixture of dyes and ammonia and hydrogen peroxide. This combination can cause irreversible damage to the keratin matrix of the hair fiber. Furthermore, in order to be effective, the process requires some mode of swelling of the hair to allow for the penetration of the dye. In the case of tint impartation, whereby the deposited color is a shade or tone lighter than the naturally underlying color, a bleaching of the natural color is required.
Due to the attention that has been given to hair dyeing, the mechanisms involved in the action of the dye formation are well understood. In addition, the damage done to the hair fibers is also well-known. In particular, some characteristics of this damage are the dimmunization of the structural integrity of the hair fibers, as evidenced by the loss of resiliency and increased porosity or capability to uptake water.
As is apparent from the preceding discussion, numerous attempts and extensive effort has been expended through the long history of dye use to achieve a commercially successful dye product. However, no such product has been attained which is capable of providing a universally applicable, commercially acceptable product which overcomes all of the known drawbacks. In addition, the prior art dye systems have often proven to be expensive, while providing only limited or partial success.
Therefore, it is a principal object of the present invention to provide a permanent or long lasting dye composition for use on human hair which is non-toxic and capable of being easily and successfully employed on all desired hair fibers with consistent, repeatable and predictable coloration results, while also imparting a long lasting conditioning effect on the hair fibers.
Another object of the present invention is to provide a permanent dye composition having the characteristic features described above which is long lasting, durable and incapable of being washed from the fibers.
Other and more specific objects will in part be obvious and will in part appear hereinafter.