US2286687A - Fingernail enamel remover - Google Patents

Description

Patented June 16, 1942 rmenmvau. ENAMEL aEMovER William F. Ochs, Mllltown, N. 1., assignor to E. I. du Pont de Nemours a Company, Wilmington,

Del., a corporation of Delaware No Drawing. Application September 28, 1939, Serial No. 296,915

2 Claims.

This invention relates to finger nail enamel' remover compositions and mor particularly to enamel removers of a creamy, non-flowing consistency.

The widespread and increasing use of nitrocellulose lacquer enamels for decorating finger nails has resulted in compositions highly resist ant to the softening and cleaning effects of soap and detergent solutions. Their removal from the nail is generally accomplished through the use of a liquid remover consisting of suitable lacquer solvents which, while effective, tend to remove the natural oil from the nail and the skin surrounding the nail. Those having the greatest solvent power are generally very volatile so that excessive amounts of cleaner are required for satisfactory removal of the tough, adherent lacquer enamel.

This invention has as its object the provision of a composition having a vigorous solvent action on finger nail enamels. A further object is the provision of a composition which does. not embrittle the nails or remove thenatural oils from the adjoining skin. A still further object is to provide a composition which can be easily applied and which will soften the nail enamel so that it can be completely removed from the nail by simple wiping with a clean fibrous or woven sheet. Another object is the provision of a composition which while working rapidly is sufiiciently solvent retentive that the user is not required to rush the cleaning operation because q further object is to provide a composition which is readily removed by wiping, to the extent that the adhesion of subsequent coats of enamel is not impaired. Another object is the provision of a composition highly stable under usual conditions of exposure, during storage, sale and subsequent use and which retards the evaporation and loss of the active volatile solvent ingredients. A still further object is the provision of a nail enamel remover composition of smooth creamlike consistency, which eliminates accidental spilling on furniture and clothing with resultant unsightly marring. Other objects will appear hereinafter.

These objects are accomplished by th following invention wherein I disperse active liquid cellulose nitrate solvents in a medium (for exarate liquid phase.

More particularly, I have found that whereas 7 most fatty and waxy materials suitable for cosmetic use are only indifierently soluble in the liquid nail enamel solvents, it is possible to melt these materials and solvents together at tempera- 10 very smooth texture resembling in a general way I the conventional and widely used face creams.

In practice I prefer to formulate the compositions with a carefully regulated amount of solvent in order to avoid the necessity of freeing the product from excess free liquid. I have further found that more stable creams can sometimes be prepared by thoroughly chilling the mixture, as this chilling serves to squeeze out amounts of free phase solvent which might cause serious instability of the product on exposure to abnormal temperatures, e. g., 120 F. The exact procedure employed in preparing the smooth cream remover does not form part'of my inven tion except as common procedures in the cosmetic industry have been specifically adapted to the particular ingredient'composition worked with.

Example 1' Per cent by weight Anhydrous lanolin (Wool fat) 50 Ethyl acetate (99%) fl 50 33 grams of lanolin were first melted and 67 grams of ethyl acetate added with agitation until a clear mixture was obtained. The mixture was then cooled, with continued agitation, to approximately 10 C. Some excess solvent remained at the end of the cooling operation and thiswas removed by a centrifuge. 'The final product contained of lanolin and 50% of solvent and was a soft, smooth texture, creamy mass which can be easily handled with a spatula and placed in containers or collapsible tubes. If desired 45 traces of perfume materials may be added just before cooling to mask the odor of the volatile solvent or for the purpose of obtaining a partlcularly desirable odor. j This cream when applied to a thoroughly dried finger nail enamel coating by means of a cloth ample, metallic soaps, fatty and waxy ingredior by means of the fingers completely softens the film in a few seconds with the further effect that the high percentage of lanolin disperses the lacquer film to a form which allows complete removal by gentle wiping.

A further property H by these products Erample 3 is that when a layer isapplied to a dry 1 Per cent by weight suflicient to wet and disperse it, simple washing Lanoun (anhydrous), 4.0 of the hands with soap and water will remove white beeswax 4.0 the enamel and mak unnecessary the use 5 Asiatic paramn wax 7.5 special tissues or c oth for wipin sodlum oleate (neutral) This composition is remarkably eilicient in rewater 5.0 moving the lacquer en e at the edges of the Methyl ethyl ketone 76.5 nail. Examination of the nail after removal of i the enamel shows no trace of the drying up and l0 moo whitening which is characteristic of previously available liquid removers.

It has also been found that in addition to the effect of the lanolin in assisting in dispersing the lacquer formed by the ethyl acetate, the

ethyl acetate in turn overcomes the stickiness often met with in the application of India to vthe hands. The presence of the lanolin' greatly reduces the evaporation of the volatile solvent present to the point that the odor becomes much less objectionable than when used alone, and also loss of the volatile solvent during storage and use is greatly reduced.

A variety of waxes and fatty materials may be employed in the operation of this invention, and although I prefer to employ appreciable amounts of lanolin in order to provide as much protection to the nail and cuticle as possible, I have found that combinations of waxes and fatty materials together with the active solvents produce valuable compositions.

Lanolin alone represents a soft sticky fat and products based upon it are also very soft. By the use of other waxy and fatty materials, harder by nature at room temperature, products of stiffer body and higher liquefying temperatures can be produced, as for example:

This composition was prepared by first combining all of the ingredients but the methyl ethyl ketone with moderate heating (M-75 C.) and'stirring to provide a homogeneous mixture. The methyl ethyl ketone was added with continued stirring as the mixture cooled to afford a smooth, fine grained cream. Perfume materials may be added shortly before stirring of the cooling mixture is completed.

This mixture at room temperature is a cream of very smooth texture readily handled and when app ied to an enameled finger nail, rapidly softens" the film so that it can be readily removed withgentle wiping. The nail and cuticle are leftin excellent condition for re-enameling and due to the presence of the lanolin and other materials, have been left in a soft, pliable condition.

Certain metallic soaps may also be used in combination with active nitrocellulose solvents, lanolin and waxes in order to form products of more permanent creamy structure which are also more capable of withstanding temperature extremes.

The ingredients of Example 3 were combined and heated to 65-70 C. until a clear liquid was obtained. The product .was then allowed to cool withoutagitation toform a smooth, fine grained cream, which when applied to finger nail enamels rapidly softens and disperses them so that simple wiping completely removes the enamel and leaves the nail in excellent condition for further applications of a new enamel coating.

I have found that a variety of fatty and waxy materials can be used in the pursuance of my invention, provided that care is taken to recognize the fact that-the permissible amount of liquid solvent is specific for each particular fatty or waxy ingredient or combination of ingredients used. In Example 1, I have illustrated a case in which equal parts of lanolin and liquid solvent gives a cream which acts as a powerful enamel remover. In Example 2, by the use of higher melting materials in combination with lanolin, it has been possible to considerably increase the ratio of liquid solvent to waxy material. However, in compositions where no metallic soap is present, I employ substantial proportions of the fatty and waxy ingredient and prefer to have at least about 20% by weight of these ingredients present, in order to have present suificient non-volatile material to completely disperse the enamel dissolved by the active solvent to a non-coherent, non-adherent layer easily removed by wiping, or by simple washing of the hands with soap and water.

The substitution of other waxy or fatty ingredients for those shown in the examples is predicated upon; first, the experimental determination of the liquid solvent absorptive and rententive power of the ingredient, that is, the quantity of liquid which will remain completely dispersed and retained over a desired temperature range, and second, the determination" of the type of product secured, such as smooth, fine grain or coarse, flaky creams. Thus, I have found that very few fatty or waxy ingredients when used alone with a suitable liquid solvent give cream removers of commercial quality, but by selection and blending of ingredients, most waxes and fatty materials, both natural or synthetic, can be used to some degree.

I further prefer to use fats or waxes which are not mobile liquids at temperatures below about F., although in certain cases I have found it possible to use the softer materials as the dispersion of the liquid solvent in the fat or wax forms a cream paste which will not flow under its own weight at room temperatures, and in someinstances, even at temperatures up to F.

Lanolin is the outstanding example in this class,

eluded to show in effect the wide range of values secured. In this test the waxy material was heated with the liquid solvent, in this case, methyl ethyl ketone, until a homogeneous mixture was obtained. The mixture was then cooled with stirring until a temperature of 35 F. was reached. By preparing a series of compositions having varying ratios of wax and solvent, the ratio was selected which gave a stiff cream. A'sample of the homogeneous cream was then carefully weighed into an evaporating dish and the mixture heated on a steam bath until all the volatile liquid solvent had been driven off. The results are expressed as grams of liquid solvent dispersed in 100 grams of the fat or wax at the end of the cooling operation, required to give a non-flowing paste at 35 C.

Many other solvents canbe substituted for the ethyl acetate and methyl ethyl ketone described in the examples. These include all of low boiling and medium boiling organic solvents usedin the lacquer industry, which have a definite solvent action on nitrocellulose. While ,I prefer to use substantially only active nitrocellulose solvents such as ketones, esters and ether alcohols,'it is occasionally advantageous to include minor portions of one or more liquids which are specific solvents for the resin modifiers of'nitro-cellulose sometimes used in nail enamel compositions, such as the aromatic or aliphatic hydrocarbons or ethyl alcohol. Any substantial amounts of these diluents, however, serve to cut down the solvent power for nitrocellulose of the composition. Solvents of specific value include acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, butyl propionate, ethyl lactate, monoethyl ether of ethylene glycol, the acetate of monoethyl ether of ethylene glycol. I am limited in my solvents only by the degree of penetration power required and the stability of the cream formed when combined with the waxy ingredients. I prefer, however, to use solvents having a penetrating power at least equivalent to that of the monoethyl ether of ethylene glycol in order to form a product sufiiciently rapid in its action or' penetration to allow quick removal of the finger nail enamel. In preparing the cream remover in the following manner:

A film or membrane of the lacquer composition is prepared by-applying to a polished glass plate,

or a carefully supported regenerated cellulose membrane, a uniform layer of-the lacquer com-- position and allowing. the volatile solvents to evaporate. 'Mildiheating can be resorted to to speed the drying and to remove the l t traces of volatile solvent. When thoroughly dry, the films are stripped from the glass or regenerated cellulose membrane normally with the 'id of soaking in water. The excess water is eliminated by drying and the film is ready for, test? I have found that a thickness of approximately .002 inch is suitable for test purposes.

A felt pad about two inches square 'is saturated with an excess of the solvent to be tested and a two-inch squaresection of the lacquer film is immediately placed on the saturated pad. The time necessary for complete penetration of the film by the solvent is noted. The endpoint is readily determined by gently rubbing the upper side of the film with a finger. A-change from a dry surface toa tacky one is readily detected. In addition to using this test for the solvent alone, the pad can be saturated with the cream remover of the present invention, and tests made. The

penetrating value is expressed as the time in seconds required before the endpoint is reached.

Representative comparative tests have been made on a series of compositions like Example 2 except for substitution of other solvents for the methyl ethyl ketone. Solvent power tests have also been made on the solvents alone to allow comparisons.

Seconds required to penetrate lacquer film (.002 in.)

CIGSHIJ) i'e-d Straight upon Examsolvent p19 2 com tainin'g:

. Seconds Seconds Acetone 6 0 Methyl ethyl ketone... 8 12 Ethyl acetate. 12 16 n-Butyl acetate 26 38 Monoethyl ether ethylene glycol. 29 39 Liquid enamel remover (U. 3. Patent It will be seen that Example 2 which contains methyl ethyl ketone as the liquid solvent is a very powerful remover, over three times as fast -in .its action as when the monoethyl ether of ethylene glycol is used. Also, its speed of action is equivalent to that of 'the patented liquid remover, so that the added properties-of the cream compositions, I may use a single solvent or plurality of solvents of the aforementioned types.

By s'olvent power is meant the ability of the solvent to soften, dissolve and penetrate the lacquer enamel film. This is specific for" each or- Example 3 which is based on methyl ethyl ketone gave 9 seconds, which is substantially equivalent I to that of the straight methyl ketone.

In order to secure products of maximumcommercial utility, I prefer to use liquid solvents for nitrocellulose having a solvent power equal to or greater than that of mono-ethyl ether of ethylene glycol. The inferior performance of solvents having solvent. power of a lower degree in attacking and disintegrating the nail enamel film ganic liquid and can be measured most effectively when employed in the cream. removers of the present invention makes them of little commer- "cial practicability.

The preferred solvents, that is; those having a solvent power at least equal to that of monoethyl ether of ethylene glycol, are preferably into methyl ethyl ketone has been varied:

Waxy ingredients Solvents gg gg Parts by weight Parts by weight Seconds 1 Example 2.

The maximum ratio of the solvent portion of the cream remover to waxy ingredient was found to lie around 70 to 80 parts of solvent to between 30 and 20 parts of waxy ingredients. When the solvent portion is increased beyond 'this proportion, the composition shows signs of instability and free solvent separation.

Example 3 represents another embodiment of the invention in which a metallic soap is employed to provide greater stability, particularly at elevated temperatures, and to permit the use of larger proportions of liquid solvents whereby the penetrating speed and consequently the destructive action on the enamel coating is accelerated. In certain cases better results are secured when these soaps are introduced together with a small amount of water to form a cream of suitable consistency but in many instances the solubility of the soaps in the preferred solvents is such that no water is necessary, as illustrated in the following example.

These ingredients when weighed into' a container and heated to a temperature of 65-70 0.

gave a clear solution free from cloud or haze and when cooled gave a smooth, stable, fine grain cream with a penetrating or softening power substantially equivalent to that of straight methyl This example was prepared in accordance with the procedure described in Example 3.

In practice I have found that a metallic soap concentration of from 2 to 6% by weight of the total ingredients and if water is required not more than 10% of water should be used to give best results. I have also found that major dif! ferences exist in the action of different soaps, and as illustrated by the following examples, it is necessary to balance the ingredient combination until a cream of the desired stability is secured.

It is also possible to make certain substitutions. In Example 3, for instance, in place of sodium oleate I have found that sodium stearate can be used provided slightly more water is added. This is necessary apparently because the gel formed by sodium stearate is harder than that formed by sodium oleate, and the addition of slightly more water (approximately 1 part per 100 of composition) softens the mixture sufficiently to give a product substantially the same as that secured with sodium oleate. I have also found that the potassium soaps of linoleic and ricinoleic acid and the ammonium soaps of these acids can also be substituted for the sodium oleate. In the case of the potassium linoleate, -it is possible to prepare a satisfactory product without the use of water which forms one of the ingredients of Example 3. Thus, it'will be seen that water acts as a very important member of the composition when using certain soaps but is not always necessary.

In general, it has been found that in order to secure a solvent activity substantially equal to that of the liquid nitrocellulose solvent used in the composition, it is necessary to keep the concentration of bodying agent below about 20% by weight. In compositions of the type illustrated by Example 2, in order to obtain a smooth cream-like composition having a desirable degree of storage stability, it is necessary to use about 20% by weight of the waxy ingredients and generally on the order of 35% or more by weight. However, inasmuch as each wax has its own specific power of absorbing solvents without becoming liquid a is shown by the above table, the concentration of the wax when used inthe absence of metallic soap will vary greatly as the waxes are changed. When used with a metallic soap, the gelling function of the wax is of much less importance and the soap gel is the major factor of gelling strength, so that the solid ingredients may comprise from 12 to 20% of the compositions to afiord creams of the suitable consistency and maximum solvent power.

The introduction of a metallic soap into the compositions of this invention limits the number of satisfactorily operative nitrocellulose solvents. Methyl ethyl ketone produces the most satisfactory cream and represents an ideal component because of its'great solvent power for nitrocellulose. Although methyl ethyl ketone represents my preferred solvent, it has been possible to obtain creams based on the metallic soap modification of commercial utility with other nitrocellulose solvents. 99% ethyl acetate does not appear to provide the desired results either with or without water, but 85% ethyl acetate- 15% ethyl alcohol mixture gives creams of mod- -.erate stability. Acetone has not given satisfactory creams. It is possible to employ a plurality of solvents provided requirements for stability in combination with waxy materials and soap and solvent power as hereinafter described are fulfilled.

Thus, it has been shown that in the complex systems of waxes, soap and nitrocellulose solvents, a critical selection of ingredients must be made, and the resulting composition examined for (a) compatibility in the molten condition, (b) smoothness or fine grain of the final cool product, resistance to storage at higher room temperatures, and (d) penetrating or softening power for nitrocellulose coatings. The second test is one of inspection and comparison by one familiar with cosmetic creams. The heat stability can be determined by heating for periods of 110 F. or other selected temperature. critical test for stability is alternate melting and chilling of the composition to determine tendencies of the solvent to separate as a free phase or any tendency of the waxy components to form a crust at the surface, a characteristic which is Another intensified by use of certain solvents, such as the monoethyl ether of ethylene glycol.

My preferred compositions accomplish all of my objects and more particularly provide a material tending to slow up the evaporation of the highly volatile solvents, methyl ethyl ketone, to the extent that it more nearly approaches that of such materials as n-butyl acetate and the monoethyl ether of ethylene glycol, without appreciable sacrifice in penetrating power. A sample of a composition prepared according to Example 3 was placed in a small glass cold cream Jar, and in a second jar an equivalent amount of methyl ethyl ketone was exposed. After being allowed to stand at 80-85 F. for 10 hours, 53.5% of the methyl ethyl ketone had disappeared while a loss of but 0.4% occurred from the cream remover.

I prefer to use lanolin in all compositions in amounts sufflcient to make available the emollient and nail softening properties this compound is generally recognized to have. j The advantages of the compositions of the present invention are several. The new finger nail enamel remover affords powerful solvent action so that the enamel is quickly and completely removed from the nail, leaving the surface in excellent condition for re-enameling. Embrittlement of'the nail and deleterious'drying effects of the adjoining skin is avoided. In contradistinction to previously'available liquid nail enamel removers, it is not necessary to rush the cleaning operation because of excessive evaporation of the volatile solvent since the ingredients which provide the creamy consistency that characterizes the new products alsogreatly inhibit this tendency. An important advantage is apparent in the physical creamy condition of the composition which avoids accidentalspilling on furniture and clothing with resultant unsightly marring, a defect which characterizes the liquid removers now on the market. The solvent retentive property of the waxy ingredients also reduces losses. of volatile solvents from the container when open during use of the remover or when inadvertently left uncapped. The compositions are stable for long periods of time and are capable of withstanding exposure temperatures up to about 110 C. without liquefying or tending to sep'arateinto a liquid and a solid phase. Another important advantage resides in the high solvent activity which is substantially equivalent to that of the liquid solvent components of the remover when tested alone. The creamy appearance of the new products contributes 'to their salability since they closely resemble the ordinary face creams with which the customer is already quite familiar.

By the generic term waxy'material as used in the claims, I wish to include both waxes and fats of the types herein described. By the term bodying agent as used in the claims is meant a substance capable of forming a mass of creamy consistency with a cellulose nitrate solvent, for example, waxy or fatty materials and metallic soaps.

It is apparent that many widely different embodiments of the invention may be made without departing from the spirit and scope thereof; and, therefore, it is not intended to be limited except as indicated in the appended claims.

I claim: I

1. A finger nail enamel remover of creamy consistency consisting of about 4 per cent of lanolin, about 11.5 per cent of wax, from 2 to 6% by'weight of an alkali metal soap, about 5% of water, and from to of a solvent for cellulose' nitrate.

2. A finger nail enamel remover of creamy consistency having approximately the following composition by weight:

Per cent Lannlin 4 W 11.5 An alkali metal soap -I. 3 Water 5 Methyl ethyl ketone 76.5

' WILLIAM F. OCHS.