US2764168A - Method of application of strippable nail polish - Google Patents

Description

United States Patent METHOD OF APPLICATION OF STRIPPABLE NAIL POLISH Benno Herz, Flushing, N. Y.

No Drawing. Application May 26, 1953, Serial No. 357,637

5 Claims. (Cl. 132-73) This invention relates to coating processes, more par ticularly to multiple or multi-layer coatings employed for decorative and cosmetic purposes, as and for example, nail polishes and the like.

The application of nail polishes, which are utilized as a colorful and decorative accessory to the costume, has resulted in a large and wide-spread market for suitably tinted lacquer compositions. These polishes are usually formulated on a nitrocellulose base in similar fashion to high-gloss lacquer-type paint compositions whose essen tial function is not only decorative but protective as .well. The usual nail lacquers yield coatings which possess both the advantages and disadvantages of pigmented nitrocellulose lacquer films. The particular advantages of these films lie in their high gloss and rapid drying chanacten istics and in the limitless number of shades in which they may be formulated. The disadvantages of the usual nitrocellulose lacquer films is that they are not particularly resistant to flexing and, in addition, their impact resistance When present on a relatively hard base, is not as high as could be desired. Translated into the degree of performance to be anticipated from nitrocellulose films which are obtained from the ordinary nail lacquers, it is readily observed that, while attractively manicured and lacquered nails are most desirable, they do not retain their desirable and decorative appearance for very long. The lacquer coating on the nail tends to chip away quite easily under impact and flexing. Furthermore, the bond between the nail surface and the lacquer film is "readily weakened when in contact with water, leading to further chipping and cracking. As a practical matter, it is seldom, if ever, that the piece-meal repair of such damaged nail lacquer films is attemped successfully. Ordinarily, when the neat, trim and attractive appearance of one or more freshly lacquered nail surfaces is impaired by unsightly chipping and cracking, all of the film is removed from all of the nails and a fresh coating then applied. This series of steps involves softening and dissolving away the nitrocellulose film, the subsequent removal of all traces of the softened lacquer film from every portion of the nail, and the final application of a new nail lacquer film. Aside from the obvious inconvenience and time involved in this step by step operation in order to obtain a pleasing decorative effect, many individuals find that the lacquer solvents present in the coating composition and/or in the lacquer film removers exert an excessive solvent action on certain factors present in the normal keratin of the nail and render it unduly brittle. This change in the keratin renders the nail prone to break even under normal stress and, should the nail break off in an irregular manner, the result can be not only exceedingly painful but potentially dangerous due to the ease with which such injuries to the nails and fingers can become infected. All of these factors readily indicate that the methods of utilizing nail lacquer compositions may well be subject to considerable improvement.

It is, therefore, an object of this invention to provide improved means for the application of nail lacquer com- 2,764,168 Patented Sept. 25, 1956 2 positions whereby the hardened lacquer film may, when so desired, be readily stripped from the nail without employing solvent compositions.

Another object of this invention is the provision of a basing composition suitable for use as an undercoating over which the usual nail lacquers may be applied. As a specific feature the basecoating is readily yieldable upon impact thus rendering it shock-resistant and capable of absorbing sharp blows on the formed nail lacquer film without undue chipping of the film.

A further object of this invention is the provision of a novel combined base and lacquer coating for nails which does not require solvent compositions for removal but may be physically separated from the nail surface in any convenient manner. In accordance with this feature of the invention therisk of damage to the nails and adjacent skin incident to employing solvents is minimized.

A further object of this invention is to provide a method of applying nail lacquer coatings which will yield a durable, shock-resistant and substantially non-chipping base. Other objects of this invention will. appear from the following detailed description.

In accordancewith features of the present invention, the application of nail lacquer compositions maybe rendered far more serviceable and satisfactory, and the films applied may be readily removed by a mere physical stripping operation (not involving the use of solvents) if the surface to which the nail lacquer composition is to be applied is precoated with a base comprising a filmforming resin compound having a basis of a vinyl chloridevinyl acetate copolymer. Preferably, the vinyl chloride vinyl acetate copolymer is one of relatively high molecular weight and contains from to 91% of vinyl chloride in said copolymer, the remainder being vinyl acetate.

In formulating the base coating composition, it is preferable that an easily flowable solution be utilized in order that the base coating formed will provide a smooth and even base upon which the nitrocellulose lacquer film is to be deposited. A balanced solvent system is essential to provide a desirably rapid evaporation of the solvent and subsequent setting of the film-forming copolymer. The proportion of solvent may vary depending upon the desired fiowability of the coating composition. Preferably, the vinyl chlonide-vinyl acetate copolymer should be dissolved in a sufficient amount of the balanced solvent system so that the solution employed contains from 15% to 20% solids, by weight. Solutions .in this range of consistency give a satisfactorily thin base coating of said vinyl chloride-vinyl acetate copolymer capable of receiving a film of the nitrocellulose nail lacquer without yielding an excessively heavy or built-up appearance due to the presence of the copolymer base coating beneath the final pigmented nitrocellulose lacquer coatmg.

in preparing the vinyl chloride-vinyl acetate copolymer base coating composition, various combinations of volatile solvents and thinners may be employed in combination with suitable plasticizers to yield a strippable coating having the desired properties of softness and flexibility. Generally, ketones are the most satisfactory solvents for vinyl chloride-vinyl acetate copolymers. Among the more suitable volatile ketone solvents which are useful there may be mentioned methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, acetone, methyl amyl ketone, cyclohexanone, etc. Other solvents which are satisfactory are dioxan, isopropyl acetate, mesityl oxide and propylene oxide. The more highly volatile ketones are preferred as they tend to yield more rapidly drying coatings.

As diluents, various organic liquids maybe employed. Toluene is a highly satisfactory thinner as are xylene and the petroleum naphthas. The commonly used petroleum naphtha fraction known in the trade as Solvesso No. 1 and Troluoil are quite satisfactory. Chlorinated solvents and diluents are also useful but have the disadvan tage that their vapors may be toxic if an unduly high concentration of solvent vapor is allowed to build up in the area in which the base coating composition is employed. Normally, however, the chlorinated solvents may be utilized safely from the toxicity standpoint inasmuch as the usual base coating application on the several nails of each hand requires such a relatively small amount of the coating composition that the concentration of chlorinated solvent vapor in the air is never in the range where there is any question of danger. The outstanding advantage of the chlorinated solvents, on the other hand, lies in their non-inflammability which is a major safety factor in connection with a composition which is to be utilized to a great extent as a domestic proprietary composition. Thus, carbon tetrachloride, ethylene dichloride and trichlorethylene may be utilized as either solvents or diluents, or both, or in admixture with other solvents or diluents in preparing the base coating compositions.

Suitable plasticizers are included in the copolymer base coating composition in order to yield a vinyl chloridevinyl acetate copolymer film which will exhibit a reasonably satisfactory degree of flexibility in service and a sufficient degree of softness to act to cushion any impact on the nitrocellulose lacquer coating which is subsequently applied. Plasticizers compatible with said copolymers and suitable for use in said vinyl chloride-vinyl acetate copolymer compositions are butoxyglycol phthalate, tricresyl phosphate, butyl phthalyl butyl glycollate, butoxyglycol adipate, triglycol di-Z-ethyl butyrate, ethyl phthalyl ethyl glycollate, methoxy glycol phthalate, etc. Usually, the plasticizer may be present in the base coating composition in an amount of from 15% to 35% by weight, based on the weight of the copolymer present. In some cases, where the plasticizer is fully compatible, it may be employed in amounts of as much as 50% by weight of the vinyl chloride-vinyl acetate copolymer for maximum flexibility.

In order further to illustrate my invention but without being limited thereto the following examples are given:

Example I A solution is prepared of the following components in the following proportions:

Parts by weight Vinylite VYHH Methyl isobutyl ketone 45 Toluene 42 Butoxy glycol phthalate 2.5 Tricresyl phosphate 0.5

lacquer is then easily applied. A highly satisfactory combination film is obtained consisting of a vinyl chloridefvinyl acetatecopolymer base coating and a pigmented nitrocellulose surface coating. The combination is outstanding for its durability and resistance to chipping, cracking, impacting, and the like.

Example 11 Q A satisfactory base coating for nitrocellulose nail lacquers may also be applied by utilizing the following composition.

4 Parts by weight Vinylite VYNS 12 Carbon tetrachloride 42 Propylene oxide 42 Triethylene glycol di-2-ethyl butyrate 4 Vinylite VMCH 2 Cyclohexanone 10 Methyl ethyl ketone 21 Methyl isobutyl ketone 25 Solvesso No. 1 30 Tricresyl phosphate l Butoxy glycol phthalate 2 The value of the foregoing composition lies in the fact that although it may readily be stripped from the nail surface when desired, it possesses greater air-dry adhesion than compositions which do not contain VMCH copolymer resin. The latter, also a product of the Bakelite Company, a division of Union Carbide and Carbon Corporation, contains a small (0.7% to 1%) proportion of maleic acid in the vinyl chloride-vinyl acetate copolymer. The presence of the free carboxyl groups promotes increased adhesion yet permits ready stripping of the base coating when it is desired to remove the pigmented nitrocellulose nail lacquer which is coated thereon.

Other commercially available preparations comprising a plasticized and stabilized solution of a vinyl chloridevinyl acetate copolymer in ready-to-apply form may also be utilized as the base coating. Thus, for example, Tygofilm TP-217, a product of United States Stoneware Co. is also quite suitable when properly diluted with the thinner provided so as to yield a readily brushable composition which dries rapidly to a clear base coating. The film-forming component of this commercial composition is a vinyl chloride-vinyl acetate copolymer of a type identical with or similar to Vinylite VYHH in a balanced solvent mixture consisting of solvents and a diluent as well as a plasticizer. The solvent normally employed consists of a mixture of cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone and a high flash naphtha diluent, the plasticizer being one or more of those previously indicated as being suitable. The commercial preparation normally contains about 28% solids and this is preferably cut considerably by the addition of commercial thinner TP91 (consisting of methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and high flash naphtha) so that the solids content is reduced to 15% to 18%. This yields a readily flowable composition which may be satisfactorily brushed out and which dries rapidly.

The nitrocellulose nail lacquers which may be employed are readily available in countless shades and among the polishes which may be utilized as an overcoating in accordance with my invention are those manufactured by Helen Neuschaefer, Revlon and Cutex.

These compositions comprise nitrocellulose as the filmforming component and a plasticizer in a volatile solvent mixture suitably pigmented to yield the desired shade. The nitrocellulose employed is preferably one of low viscosity, say 0.25 to 0.5 second, and one which is soluble in the usual ester and ketone solvents. The RS grade containing 11.8% to 12.2% nitrogen is quite satisfactory and is available in the desired low viscosity range. As suitable plasticizers, there may be mentioned di-n-butyl phthalate, tricresyl phosphate and triphenyl phosphate. The preparation of these nail lacquer compositions involves the milling of the pigment to a suitably fine dispersion and the addition of the nitrocellulose, solvents, diluents and plasticizer to reach the final commercial composition.

In applying said nail lacquer over the vinyl chloridevinyl acetate copolymer base coating, care must be taken to avoid overbrushing, as is the case where no base coat ing is utilized, due not only to the fact that the rapid evaporation of the volatile nitrocellulose solvent makes the nitrocellulose coating quite tacky almost immediately after application, but also due to the fact that these same solvents exert some degree of solvent action on the base coating. Normal precautions to avoid overbrushing of the pigmented nitrocellulose nail lacquer are usually sufficient, however, to avoid any undesirable effect upon the vinyl chloride-vinyl acetate copolymer forming the strippable base coating.

It is understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. Process for the application of a film-forming nail lacquer composition, which comprises base-coating the finger nail to which the lacquer is to be applied with a strippable film-forming liquid composition comprising a vinyl chloride-vinyl acetate copolymer resin dissolved in a volatile solvent mixture, allowing the solvent to evaporate and to leave a coating of vinyl chloride-vinyl acetate copolymer resin film on the surface, and then applying a film-forming nail lacquer composition to the coated surface.

2. Process for the application of a film-forming pigmented nitrocellulose nail lacquer composition, which comprises base-coating the finger nail to which the nitrocellulose lacquer is to be aplied with a strippable filmforming liquid composition comprising a vinyl chloridevinyl acetate copolymer resin dissolved in a volatile solvent mixture, allowing the solvent to evaporate to leave a vinyl chloride-vinyl acetate copolymer resin film on the surface, and then applying a film-forming pigmented nitrocellulose nail lacquer composition to the surface of the copolymer resin film.

3. Process for the application of a nail lacquer, which comprises base-coating a finger nail surface to which the nail lacquer is to be applied with a strippable film-forming liquid composition comprising a vinyl chloride-vinyl acetate copolymer resin containing to 91% vinyl chloride dissolved in a volatile solvent mixture, allowing the solvent to evaporate to leave a vinyl chloride-vinyl acetate copolymer resin film on the finger nail surface, and then applying nail lacquer over the base coating of the copolymer resin film.

4. Process for the application of a film-forming pigmented nitrocellulose nail lacquer composition which comprises base-coating the finger nail to which the nitrocellulose lacquer is to be applied with a strippable filmforming liquid composition comprising a solution of a mixture of a vinyl chloride-vinyl acetate copolymer resin containing 85 to 91% vinyl chloride and a vinyl chloridewinyl acetate copolymer modified with maleic acid dissolved in a volatile solvent-diluent mixture, allowing the solvent and diluent to evaporate and to leave a vinyl chloride-vinyl acetate copolymer resin film on the surface, and then applying a film-forming pigmented nitrocellulose nail lacquer composition to the surface of the copolymer resin film.

5. Process for the application of a film-forming pigmented nitrocellulose nail lacquer composition, which comprises base-coating the finger nail to which the nitrocellulose lacquer is to be applied with a film-forming liquid composition comprising a solution of a mixture of a vinyl chloride-vinyl acetate copolymer resin contain ing 85% to 91% vinyl chloride and a vinyl chloridevinyl acetate copolymer modified with maleic acid dissolved in a plasticizencontaining volatile solvent-diluent mixture, allowing the solvent to evaporate and to leave a vinyl chloride-vinyl acetate copolymer resin film on the surface, and then applying a film-forming pigmented nitrocellulose nail lacquer composition to the surface of the copolymer resin film.

References Cited in the file of this patent UNITED STATES PATENTS September 1952, pp. 1241 to 1255. (Copy in Div. 43.) Sulzberger: Journal of Investigative Dermatology, vol. 11, July 1948, pp. 67 to 72. (Copy in Sci. Libr.)

Hilfer: Drug and Cosmetic Industry, vol. 64, April 1949, pp. 432, 433. (Copy in Sci. Libr.)