The present invention relates to compositions and processes for applying strong protective acrylic coatings to fingernails and toenails with or without artifical extensions to the nails.
Numerous techniques for applying protective coatings for fingernails, with or without extensions to the nails, exist today. The types of artificial nails produced by these techniques can be classified as (1) glue-on nails, (2) nail wraps, (3) sculptured nails, and (4) nail dips.
Glue-ons are pre-formed plastic fingernails having the desired, usually extended shape of the natural nail. These are glued directly on to the fingernail. Because of the wide variety of nail shapes, glue-on nails are difficult to fit. As the nails grow, the glue-on nails move distally creating an unsightly ledge across the base of the nail. This is repaired either by removing the artificial nail and attaching a new one or by filling in behind the ledge by a sculpturing technique as described below. The former repair is expensive because it must be performed every two to three weeks and the removed nail cannot be reused. The latter repair requires the skills of a scupltured nail technician.
In the nail wrap method a piece of paper or fabric is cut to the shape of the natural nail, glue is applied to the natural nail and the paper or fabric is pressed into the glue. The paper or fabric is then smoothed insofar as possible and folded over the free edge of the nail. The folds are glued to the underside of the nail and more glue is applied to the paper or fabric in successive layers until the surface is smooth. This type of artificial nail has many problems. First of all, the nail is made if glues, usually the lower cyanoacrylate esters, which do not produce a particularly strong nail. The single lamina of paper or cloth adds little strength to the composite. Secondly, the surface of the natural nail is a complex curve and it is difficult for the paper or fabric to conform to the surface without forming folds. Under the nail, the folded over paper or fabric forms convolutions which are unattractive when viewed from the edge or from underneath. Moreover, these folds harbor dirt and microorganisms. If edge folds are not used or if the nails are trimmed, the edge is ragged and readily delaminates. As with glue-ons, the artificial nails move distally as the nail grows and must be filled in or the artificial fingernail must be removed and replaced with a new nail wrap.
Nail sculpting has become popular with those who are unsatisfied with the methods described above. However, nail sculpting requires a great deal of training and skill. In this method, preparation of the natural nail is important because the thick, tough acrylic nail becomes permanently attached to the point where it is applied. The nail is first cleaned, roughened, and treated with a bromide. It is then coated with glue, usually a cyanoacrylate ester, or a primer containing methacrylic acid which binds the acrylic to the natural nail. Then the sculpturist wets a small brush with a liquid consisting of a blend of mono-, di- and trimethacrylate esters and a promoter, usually N, N, dimethyl-para-toluidine which is capable of inducing the decomposition of benzoyl peroxide at room temperature. The wetted brush is then dipped into a finely powdered polymethacrylate ester which contains benzoyl peroxide. The liquid and powder form a dough which begins to cure (i.e., harden or polymerize) immediately. The dough is then quickly placed onto the prepared nail and smoothed or sculptured in place. More dough is added until the nail is covered and filled to the desired, uniform thickness and shape. Filing, buffing and, sometimes, the addition of more dough result in a strong, albeit thick nail ready for polish. If the fingernail is to be extended, a form with a non-adhering upper surface is placed under the edge of the nail and the sculpturing is continued out over the form. The form is removed after the dough is cured.
Extraordinary skills are required for this procedure. The dough must be of a precise consistency. If it is too thin, it is runny and cures slowly and sometimes does not cure at all. If it is too thick, it is weak due to air bubbles and stress cracks. If the sculpturist pauses too long between applying each brush full of dough, the bond is poor and the nail cracks easily. If the dough is not placed and worked skillfully an excessive amount of filing is required to remove humps and lumps to produce an attractive nail.
Recently, a method of applying arificial fingernails called nail dipping has been introduced. In this method, the natural nail is coated with a high-viscosity glue of the cyanoacrylate ester type. The wetted nail is then briefly dipped into a powdered, uncross linked polymethacrylate ester. Any excess powder is brushed off and the surface is smoothed partially by filing and light buffing. This rough surface is then sealed or filled in by applying a low-viscosity cyanoacrylate ester glue in one or more coats until the powder no longer protrudes above the surface. The surface is then filed and buffed and is ready for the application of nail polish.
It is apparent that this method circumvents the fitting problems of glueing-on and wrapping and the skills required of sculpting. However, the finished nail is not strong. The cyanoacrylate ester glues, although adherent, are not structurally sound. Layers as thick as artificial nails if not supported by opposing substrates break easily. The uncross linked polyethylmethacrylate powder is weak per se and lends little toughness to the polycyanoacrylate ester surrounding it. Thus, the dip process nail may be stronger than nail polish but it is much weaker than a sculpted acrylic nail.
It follows, therefore, that there is a present need for strong, easily appliable, repairable, fillable, artificial nails and a better procedure to repair and strengthen natural nails and to apply the artificial nails.