Field of the Invention

The present invention relates to novel, quick drying nail enamel compositions which dry in less than about three minutes. The compositions of the present invention preferably dry in a period of time no greater than about two minutes and more preferably dry in a period no greater than about 90 sec¬ onds. Compositions drying in a period less than 60 seconds are especially preferred and are also described. The composi¬ tions of the present invention have acceptable static vis¬ cosities ranging from about 400 to about 1200 centipoises and may accommodate numerous pigments to produce nail enamel com¬ positions exhibiting favorable wear characteristics, including acceptable durability and gloss.

The compositions of the present invention comprise a primary film-forming polymer, a secondary film-forming polymer, for example, a resin which functions to strengthen the primary film-forming polymer and improve the adhesion and gloss of the nail enamel, a plasticizer, a thixotropic agent, preferably an organoclay thixotropic agent and a solvent system containing acetone in an amount no less than about 4.5% and preferably no less than about 13% by weight of the com¬ position and at least one additional solvent and preferably including a wetting solvent and a diluent solvent. In preferred compositions according to the present invention, acetone comprises about 15% to about 25% of the total weight of the composition. In a particularly preferred embodiment, the nail enamel compositions according to the present inven¬ tion contain about 18% to about 22% by weight acetone. Preferably, the nail enamel compositions of the present inven tion also contain a pigment for coloring the nail coating, in addition to other additives such as preservatives, stabilizer and fragrances. Other nail enamel compositions which do not contain a thixotropic agent ot pigment are also disclosed by the present invention.

SUBSTITUTE SHEET

Back round of the Invention

A large number of methods and compositions for beautifying and strengthening the nails of humans are well known. Prior art methods include coating the nail of an animal, including humans with a composition including a film forming polymer and additional ingredients such as pigment, plasticizer and solvents or alternatively, attaching preform artificial nails to human nails with adhesives. Additional methods include adding crosslinkable polymers to nail coatin compositions to mend, strengthen and elongate natural nails and repairing nails with a fabric patch.

Most nail enamel compositions presently on the marke or disclosed in the prior art dry in five minutes or longer. Even those riail enamels that claim to be quick-dry, i.e.-, dr in about five minutes, are often not truly dry but rather ar only dry to the touch. When a purportedly "dry" nail enamel of the prior art brushes up against a hard surface, the nail enamel often smudges, leaving tack.

One nail polish drying composition disclosed in Unit States Patent Number 4,798,720 prepared from commercially available top coat nail polish, acrylic nail powder, acrylic nail primer and the adhesive "crazy glue" is described as being used in combination with commerically available colore nail polishes to alter the drying time of the nail polish to period of more than three minutes. The compositions of-this patent are used as base coats in combination with commercial available pigment containing nail polishes. The patent clai to dry from one to seven coats of pigment containing nail polish within a period ranging from about three to five minutes. This composition functions as a base coat or .top coat and unlike the composition of the present invention, m be used in combination with a commerically available pigmen nail polish to provide a lasting pigmented nail enamel fini

A nail polish which can be used to coat a natural o synthetic nail which dries in less than three minutes witho

requiring an additional application of a base coat or top coa as is disclosed in the prior art would be very desirable. Nail polishes which dry in a period of less than 150 seconds would be even more desirable, as would polishes that dry in periods less than about 90 seconds. A nail polish compositio which would dry in a period of no greater than about 60 sec _¬ onds would be especially useful in situations where "drying" time is important.

Working women need to have a product which can be easily applied and which dries in the shortest amount of time to avoid a situation where they are simply wasting precious time waiting for their nail polish to dry. In the manicure and pedicure industries, a pigmented nail polish composition which can dry in a period less than three minutes would pro¬ vide a significant advantage over the prior art compositions.

Solvent mixtures for nail enamels of the prior art have covered a wide range of compositions and have included a many as six or seven solvents to control flow, viscosity, evaporation rate and drying time of the enamel. As discussed in Peirano, "Nail Lacquers and Removers", Cosmetics Science and Technology, Interscience Publishers, Inc., 1957, solvent or mixed solvents used as the volatile portion of nail ename are of prime importance because of their direct effect on ea of application of enamel, on the rate of drying and hardenin on the viscosity of the enamels and on the characteristics o the final film. According to this reference, too rapid a ra of evaporation causes a poor flow of the enamel and also giv an uneven, streaky application. The reference also cites th importance of proper solvent balance during the drying stage of the lacquer. In general, due to the wide differences in evaporation rates of the solvents which are included in the prior art compositions, these compositions undergo many changes during the drying of the film. For example, during the course of evaporation of the solvent from the nail ename on the nail, differential evaporation of the solvents within the composition may result in the presence of higher con¬ centrations of certain solvents during drying, which in turn

O 91/08731

-4-

creates precipitation of the film forming polymer, resin and/or plasticizer, thereby destroying the integrity of the film and the appearance of the enamel. If the solvent become too lean to maintain the solubility of the resin in solution, the resin will precipitate, also resulting in unacceptable results.

^" Another reference which provides insight into the sol vent mixtures useful in nail enamels and briefly touches the subject of drying time is an article by Harvey M. Remz, Cos¬ metics and Toiletries, Vol. 103, 70 ,(1988). In this reference, Mr. Remz points out that providing solvent balance is a complex task in formulating a nail enamel composition an briefly discusses evaporation rate and the volatility of sol¬ vents included in nail polish on page 76.

The complicated character of the nail enamel mixtures of the prior art and the many possible combinations of volatile and nonvolatile components had, until the unexpected discovery of the present invention, made the determination of a proper solvent balance from the perspective of viscosity, solubility of the individual components and the acceptability of the deposited enamel (gloss) in combination with a drying time of less than three minutes virtually impossible. Until the discovery of the present invention, the identification of the evaporation rates of the individual solvents under variou conditions had not removed the uncertainty involved in determining a suitable solvent balance incorporating quick- drying characteristics. Although the desirability of a quick drying nail enamel has been a long-felt need, the rate of drying of the nail enamels of the prior art has been limited by the aforementioned considerations. Thus, before the dis-- covery of the present invention, simply incorporating low boiling solvents did not increase the likelihood that an acceptable solvent system for nail enamels would be found or that one could obtain a nail enamel composition which dried under three minutes. In the present invention, the use of acetone in certain weight percentages of the composition, in combination with numerous solvents which rovide acce table

viscosity, creates a consistent quick-drying solvent system which provides the nail enamel with favorable characteristics of drying time, viscosity, gloss, flexibility and durability.

Acetone, also known as 2-propanone, dimethylketone and beta-ketopropane is a volatile solvent which has a boiling point of 56.5 ^β C and is miscible with an extremely large number of solvents including water, alcohol, dimethylformamide, chloroform, methylene chloride, toluene, esters, including methylacetate and ethylacetate, benzene and toluene, ethers and numerous oils and hydrocarbons, among others. A number of prior art references disclose acetone as one of a large number of solvents which are useful for formulating nail enamels. The uniqueness of acetone for use in the present invention resides in the fact that acetone will interact with solvents used in nail enamel preparations of the present invention to produce a solvent system which evaporates in under three minutes and instills acceptable characteristics which are desired in nail enamels.

It has surprisingly been discovered that the inclusion of specific weight percentages of acetone in combination with additional solvents, preferably including wetting agents and diluents in compositions for coating natural and synthetic nails containing thixotropic agents produces a nail coating composition which dries in a period of time less than about three minutes and produces a coating on a nail which is hard, flexible and has good wear characteristics including durability and high gloss. Moreover, the use of acetone in the volatile component of nail enamel compositions of the present invention within specific weight percentages provides a consistent basis upon which one of ordinary skill in the art may modify nail enamel compositions according to the present invention without dramatically adversely affecting the drying time of the nail enamel and without dramatically adversely affecting other characteristics which are required for commer cially competitive nail enamels.

SUBSTITUTE SHEET

Obiects of the Present Invention

It is therefore an object of the present invention to provide a pigmented nail polish composition containing a organoclay thixotropic agent which can be applied to natural and synthetic nails and will dry in a period of about 3 minutes, or less, preferably about two minutes or less, most preferably about 90 seconds or less and especially about 6 ₀ seconds or less.

It is an additional object of the present invention to provide a clear nail enamel containing an absence of pigment and organoclay thixotropic agent which can be used as a basecoat or top coat which dries in less than 30 seconds.

It is a further object of the present invention to provide a general method for making nail polish formulations., which will dry in a period less than three minutes.

It is still another object of the present invention to provide a nail preparation kit comprising a base adapted for forming a coating on a natural or synthetic nail and a suitable solvent system which together will provide a coating of nail enamel which dries in a period less than about three minutes.

It is still a further object of the present invention to provide a ovel method for coating nails with a pigmented nail polish composition containing an organoclay thixotropic agent which dries in a period of about three minutes or less, preferably less than about two minutes, most preferably about 90 seconds or less and especially about 60 seconds or less.

It is yet an additional object of the present inven¬ tion to provide a novel method for coating nails with a clear nail ^• enamel which can also be used as a basecoat or top coat which dries in less than 30 seconds.

SUBSTITUTESHEET

It is yet another object of the present invention to provide a number of solvent systems which may be added to standard nail polish formulations to substantially hasten the drying of a nail enamel composition to a durable, hard finish exhibiting high gloss without adversely affecting the favora _¬ ble characteristics of the complete nail polish formulation.

These and other objects of the present invention may be readily gleaned from the description of the invention which s set forth herein.

Brief Description of the Invention

In accordance with the objects of the present inven¬ tion there is provided a nail enamel preparation comprising a fluid mixture adapted for drying and hardening to form a .coat¬ ing on a nail. The fluid mixture comprises, in part, a plurality of solvents, one of which is acetone, the others being a wetting agent and a diluent. In nail enamel composi¬ tions according to the present invention, acetone comprises about 4.5% to about 35% by weight. It has surprisingly been discovered that acetone will interact with a large number of solvents within a nail coating composition to produce a com¬ position which will dry within a period of time significantly shorter than would be expected from the evaporation rates of the individual solvents. It is particularly surprising that the nail enamel compositions according to the present inven¬ tion dry in such short periods of time and provide favorable viscosity and wear characteristics including gloss and durability.

The present invention therefore relates to novel com¬ positions for coating natural and synthetic nails which dry to a hard, flexible coating exhibiting favorable characteristics of durability and high gloss comprising: a) a primary film-forming polymer; b) a secondary film-forming polymer; c) at least one plasticizer; d) at least one thixotropic agent, preferably an

-8-

organoclay thixotropic agent; e) at least one pigment; and f) an amount of acetone ranging from about 4.5% to about 35% by weight of said composition in combination with at least one solvent, said solvent preferably including a wetting agent and at least one diluent solvent said solvent combina _¬ tion dissolving said primary and secondary film-forming polymers and said plasticizer and producing a gelled composi _¬ tion in combination with said thixotropic agent having a static viscosity ranging from about 400 to about 1200 centipoises. The compositions of the present invention dry on a natural or synthetic nail surface within a period of time less than about three minutes.

In addition to the components set forth above, the compositions of the present invention may further comprise additional agents, for example, fragrances and preservatives, among others.

It is a surprising result that the nail enamel com¬ positions embraced by the present invention which include sig¬ nificant quantities of solvents which include acetone in the disclosed weight ranges and which have a static viscosity, generally ranging from about 400 to- about 1200 centipoises, preferably, approximately 800 centipoises, consistently dry in about three minutes or less. It is particularly surprising that the inclusion of certain weight percentages of acetone in combination with numerous solvents which do not otherwise dry within a period of about three minutes or less will produce nail enamel compositions which will dry in a period of time less than about three minutes, for example, about two and a half minutes, about 90 seconds or even less than about 1 minute.

In certain compositions according to the present invention which do not include thixotropic agents and pig¬ ments, an especially fast drying clear base coat or top coat formulation is presented comprising about 18% to about 35% by weight acetone, preferably about 24% to about 35% by weight

acetone, in combination with other solvents, primary film- forming polymer, secondary film-forming polymer and at least one plasticizer. Such compositions, which can be used as base coats, top coats or clear enamels, dry in a period of time less than about 30 seconds.

It is also surprising that the solvent combinations which are used in the compositions of the present invention dry in such a short period of time in a uniform fashion without streaking or precipitation of the solid material. The resulting enamel coat is uniform, hard and flexible and exhibits favorable durability, high gloss and wear character¬ istics.

In accordance with the present invention, the nail enamel compositions of the present invention include an effec¬ tive amount of a primary film-forming polymer to provide durability, hardness, gloss and adhesion to the nail enamel in combination with a secondary film-forming polymer after it dries on a nail or other flexible surface. The primary film- forming polymer is used as the base material for the nail enamel to give the nail enamel compositions their basic properties. In the present invention numerous film-forming polymers may be used as the primary film-forming polymer alone or in combination including cellulose acetate, cellulose acetate-butyrate, ethyl cellulose, numerous vinyl polymers as well as a number of methacrylate and acrylate type polymers. Additional primary film-forming polymers include, for example, nitro-starch and polyvinyl acetate, methacrylate and nitrocel lulose, polyvinylacetate and nitrocellulose, polyurethanes, polyamides, alkyl vinyl ether-maleic anhydride copolymer, polyvinyl butyral, siloxanylalkyl ester-( eth)acrylate copolymers, polyacrylic and polyethyleneimine/polyepoxide copolymers, among others. Preferably, nitrocellulose is used as the primary film-forming polymer in the present invention.

In addition to the primary film-forming polymer, the compositions of the present invention also include an amount of a secondary film-forming polymer effective to strengthen

the primary film-forming polymer and also provide the enamel coating with acceptable gloss and adhesion characteristics in combination with the primary filmr-forming polymer. Exemplary secondary film-forming polymers or resins which may be used in the present invention include, for example, drying and nondry- ing alkyd resin, polyvinyl resins , for example polyvinyl acetate, polyester resins, acrylate and methacrylate resins, alkyd resins, melamine resins, polya ides, ester gums, rosin and polyesters and polytetrahydrofuran and arylsulfonamide- formaldehyde resins, for example toluene sulfonamide- formaldehyde resin, among others. These secondary film- forming polymers are added to"the primary film-forming polymers of the present invention to strengthen and add accep¬ table wear characteristics in combination with the primary film-forming polymer. Toluene sulfoήamide-formaldehyde resin, a condensation product of formaldehyde and toluene sulfonamide (available from for example, Akzo Chemie America, Chicago, Illinois as Ketjenflex MS-SO* ²¹ ") , is especially preferred- for use as a secondary film-forming polymer in the present inven¬ tion.

In addition to the primary and secondary film-forming polymers the compositions according to the present invention also comprise at least one plasticizer, preferably for exam¬ ple, dibutyl phthalate and most preferably a mixture of dibutyl phthalate and camphor to add characteristics of flexibility to the nail coating. Certain secondary film- forming polymers, for example, toluene sulfonamide/epoxy resin and toluene sulfonamide/epoxy resin butyl acetate, available from Teleche ische,. Newburgh, New York, which have acceptable plasticization characteristics may be used in certain embodi¬ ments of the present invention without the need to include a separate plasticizer.

In addition to the above-described components, the compositions of the present invention may additionally com¬ prise a thixotropic agent, preferably an organoclay thixotropic agent, for example, hectorite clays modified with quaternary ammonium compounds, such as the Bentones^m _f avail-

-li¬

able from NL Industries, New Jersey, USA as suspension agents for the nail polish and in addition a coloring substance or pigment to give the preparation a cosmetically acceptable shade and to opacify the film.

In addition to the components set forth above, the compositions of the present invention may also include further additives including stabilizers, preservatives, fragrances and anti-oxidants, among others.

To provide acceptable static viscosities within the range of about 400 to about 1200 centipoises, the nail enamel compositions of the present invention which contain an organoclay thixotropic agent generally comprise about 50% to about 75% (and in certain cases up to about 80%) by weight solvent, preferably about 60% to about 70% by weight solvent, and most preferably about 64% to about 69% by weight solvent.

In addition to the disclosed weight percentages of acetone which are used in the present invention, other exemplary solvents include for example, ethyl acetate, methyl acetate, propyl acetate, methanol, ethanol, isopropanol, n- butanol, n-butyl acetate, methylchloroform, methylene chloride, toluene, xylene, additional aromatic (containing phenyl groups) solvents and mixtures thereof, among others, including amyl acetate, numerous ethers, numerous ketones including methylethylketone and alkanes including pentane, cyclopentane, hexane, and cyclohexane, among others, in vary¬ ing weight percentages. In addition to the above-named sol¬ vents, other solvents which may be used in the present inven¬ tion include, for example, cyclic ethers such as tetrahydrofuran and 1,4-dioxane, among others. High boiling solvents, for example, cellosolve, butyl cellosolve acetate, cellosolve acetate, methyl cellosolve acetate, butyl cel¬ losolve, ethyl cellosolve and phenylated solvents including xylene may also be used. Of course, these high-boiling sol¬ vents, because of their tendency to increase drying times ar included in weight percentages in compositions of the presen invention in amounts consistent with producing a nail compos

tibn which dries in about three minutes or less. _O ne of ordinary skill in the art will know to vary the weight per _¬ centages of acetone and the .other solvents used in composi _¬ tions of the present invention within the teachings of the present invention to produce a large number of acceptable sol _¬ vent combinations for use in nail enamel compositions which dry in a period of about three minutes or less.

In certain aspects of the present invention it has been found advantageous that the solvent system used in the nail enamel compositions according to the present invention include, in addition to an effective amount of acetone to reduce the drying time of the nail enamel to below three minutes, a wetting agent and a diluent solvent. A wetting agent is included in compositions according to the present invention to provide favorable interaction with the nitrocel¬ lulose film-forming polymer and to a lesser extent, other com¬ ponents in the formulation.

In the present invention, it has been found advantageous to include acetone in amounts ranging from about 4.5% to about 35% (preferably above about 7% within this range) , more preferably about 13% to about 30% and most preferably about 15% to about 25% by weight acetone. In certain embodiments of the present invention in which pigment and a Bentone ^tm thixotropic agent such as Bentone RSNC^ ¹ " or Bentone 27 ^tm . is included, about 18% to about 22% by weight acetone has been found to be especially advantageous to pro¬ duce nail enamel compositions having fast drying times.

In addition to acetone, certain aspects of the presen invention also include a wetting agent such as an alcohol, fo example, ethanol, isopropanol, methanol or n-butanol. The amount of wetting agent for use in the nail enamel composi¬ tions according to the present invention may range from about 0.1% to about 25% by weight, above which amount, the viscosit of the compositions may tend to fall below commercially accep table levels. The amount of wetting agent is included in com positions according to the present invention to provide a

favorable interaction with the primary film-forming polymer, especially nitrocellulose. Generally, however, wetting agents in amounts of less than about 10% and preferably less than about 5% by weight of the nail enamel composition are used. In most commercially available nitrocellulose, a wet _¬ ting agent such as isopropanol is often included.

The compositions of the present invention also generally include at least one additional solvent other than acetone or a wetting agent, which, for purposes of defining the present invention is the diluent solvent. The diluent solvent may be any solvent which is compatible with the wet¬ ting agent and acetone and in combination with the acetone and wetting agent provides solubility characteristics which are consistent with dissolving the primary-film forming polymer, the secondary film-forming polymer and the plasticizer arid with forming a gel with the thixotropic agents which are- used in the present invention. In addition, diluents may be chosen to increase the viscosity of the formulations as well, lϋxemplary diluents for purposes of the present invention include esters, preferably an ester of acetic acid such as methyl acetate, ethyl acetate, propyl acetate, n-butyl acetate, amyl acetate, among others and mixtures of these esters especially including mixtures of ethyl acetate and n- foutyl acetate in amounts ranging up to about 50% or more by weight of the nail enamel compositions, and preferably about 20% to about 30% by weight of the nail enamel compositions.

Other diluents for use in the present invention include the aromatic diluents, for example, toluene, xylene and certain naphtha derivatives. Toluene is a diluent which is used in many commercial nail enamels. Because of the regulatory implications of using certain of these diluent sol vents, a number of substitutes for toluene may be included in compositions of the present invention. Substitutes for toluene include for example the previously mentioned diluent esters of acetic acid such as methyl acetate, ethyl acetate, propyl acetate, n-butyl acetate and amyl acetate and also include certain chlorinated hydrocarbons, for example,

methylene chloride, methylchloroform, various ketones other than acetone including methylethyl ketone and various hydrocarbons including hexane, heptane, cyclohexane and pe tane and certain ethers, including for example cylic ethers such as tetrahydrofuran and 1,4-Dioxane, petroleum ether and. higher boiling ethers, among others. These diluent solvents may be used to replace toluene or may be used in combination with toluene.

It is an especially surprising result that a nail enamel composition containing acetone in an amount ranging from about 4.5% to about 35% by weight of the final composi¬ tion in combination with a solvent system which otherwise does not dry or evaporate within a period of about three minutes on a human or artificial nail will dry in a time period of about three minutes or less. The solvents which are included with acetone in the present invention are chosen for their ability, in combination with acetone, to dissolve the primary film- forming polymer, the secondary film-forming polymer and the plasticizer and for their ability to provide a final static viscosity in combination with the solids of the compositions of the present invention including pigment and thixotropic aσent in the range of about 400 to .about 1200 centipoises, preferably about 800 centipoises. In the case of compositions which include organoclay thixotropic agents, solvents are chosen for their ability to provide adequate gel formation of the thixotropic agent(s) as well as for the previously described characteristics of dissolving the solid components of 'the nail enamel. In basecoat/topcoat nail enamel composi¬ tions of the present invention, the viscosity ranges beyond that range disclosed for compositions containing a thixotropic agent and pigment.

The present invention also relates to a nail prepara¬ tion kit comprising a polymer base adapted for drying and har dening to form a pigmented coating on a nail upon mixture of the base with a suitable solvent mixture, the solvent mixture comprising an amount of acetone comprising at least about 4.5 to about 35% by weight of the final nail enamel composition

including solids in combination with a plurality of solvents which include acetone, a wetting agent and a diluent and which dissolve a primary film-forming polymer, a secondary film- forming polymer and a plasticizer, the composition having a final static viscosity ranging from about 400 to about 1200 centipoises, preferably about 800 centipoises. In addition to primary film-forming polymer, secondary film-forming polymer and plasticizer, the polymer base additionally comprises an organoclay thixotropic agent and at least one pigment and optionally, other additives including preservatives and fragrances, among others. In this nail preparation kit aspect of the present invention, the polymer base comprises about 25% to about 50% by weight of the final nail enamel composition to be applied to the nail and the solvents comprise about 50% to about 75% by weight of the composition, preferably about 60% to about 70% by weight and most preferably about 64% to ^bout 68% by weight solvent.

The nail preparation kit aspect of the present inven¬ tion also includes top coat, basecoat and clear nail enamel compositions which contain at least about 18% to about 35% by weight acetone, preferably at least about 24% to about 35% by weight acetone and an absence of pigment and thixotropic agent. These compositions dry in a period of time no greater than about 30 seconds and have viscosities which often range outside the range generally established for compositions con¬ taining thixotropic agent.

In still another aspect of the present invention, sol vent mixtures particularly adapted for use in combination wit pigmented polymer bases for use in nail enamel compositions are also disclosed. In this aspect of the present invention, .solvent mixture comprises acetone in an amount equal to about 6% to about 70% by weight of the solvent mixture and at least one wetting agent and at least one diluent solvent to produce a solvent mixture which, in combination with a polyme base containing an organoclay thixotropic agent adapted for use in pigmented nail enamel preparations, provides a gelled nail enamel preparation comprising at least about 4.5% to

about 35% by weight acetone in combination with a wetting agent and a diluent, said nail enamel composition having a static viscosity ranging from about 400 to about 1200 centipoises and drying in a period less than three minutes to hard, flexible pigmented surface having acceptable wear characteristics including durability and high gloss. Solvent systems for use in basecoat, top coat and clear enamel com _¬ positions containing at least about 24% by weight acetone up to about 70% by weight acetone.

In accordance with a further aspect of the present invention, the present invention includes a process for making the pigmented nail enamel compositions of the present inven¬ tion. In accordance with this aspect of the present invention nail enamel compositions of the present invention are for¬ mulated by first mixing a solvent combination including an amount of acetone equal to about 6% to about 70% by weight of the solvent mixture in combination with a wetting agent and diluent solvent to produce a solvent mixture. Thereafter, a primary film-forming polymer, a secondary film-forming polymer and at least one plasticizer is added step-wise in any order in conjunction with vigorous mixing, until a viscous solution is produced. The compositions produced according to this method can be used as colorless nail polishes or alterna¬ tively, as base coat and top coat formulations in conjunction with colored nail polishes. After the above solution is pro¬ duced, an organoclay thixotropic agent, for example, stearalkoniu hectorite, is added to the above-described mix¬ ture in conjunction with vigorous stirring (under strong shearing force with, for example an industrial mixer such as a Ploffmeyer industrial mixer) generally for a period of at least about one hour to produce a gelled mixture. In the last step, one or more pigments are added to the above gelled mixture to produce the rapid drying nail enamel compositions according to the present invention. The final composition produced by the method according to the present invention obtains a final static viscosity ranging from about 400 to about 1200

-en ^ip c ⁱ se-. _SUB STITUTE SHEET

While it is possible to produce the compositions of the present invention following the general procedures of the method aspect of the present invention, it is clearly preferred that all mixing of the nail enamel compositions and especially those containing an organoclay thixotropic agent, preferably stearalkonium hectorite, and pigment, be performed under high shear speed. Therefore, one of the aspects of the method of the present invention includes the use of vigorous stirring at high shear speed, for example using a Hoffmeyer industrial mixer for a period of time sufficient to produce a thixotropic gel after settling, generally at least about one hour and preferably at least about two hours.

Detailed Description of the Invention

Compositions of the present invention for coating a natural or synthetic nail comprise the following ingredients: a) a primary film-forming polymer; b) a secondary film-forming polymer; c) at least one plasticizer; d) at least one thixotropic agent; e) at least one pigment; and f) an amount of acetone ranging from about 4.5% to about 35% by weight of said composition in combination with a least one solvent, said solvent preferably comprising a wet¬ ting agent and at least one diluent' solvent said solvent com¬ bination dissolving said primary and secondary film-forming polymers and said plasticizer and producing a gelled composi¬ tion in combination with said thixotropic agent having a static viscosity ranging from about 400 to about 1200 centipoises, said composition drying on a natural or syntheti nail within a period of less than about three minutes.

In certain embodiments, the compositions according t the present invention contain an absence of thixotropic agen and pigment and at least about 18% by weight acetone in com¬ bination with a wetting agent and a diluent solvent, preferably at least about 24% by weight acetone in such sol¬ vent combination so that the drying time is less than about

seconds. These compositions may be used as clear nail enamel or alternatively as base coats or top coats for application to nails.

In addition to the above components, the compositions according to the present invention may further comprise ^" one or more additional agents, for example, stabilizers, fragrances, anti-oxidants and preservatives, among others.

The compositions of the present invention contain a primary film-forming polymer for example, cellulose acetate, cellulose acetate-butyrate, ethyl cellulose, numerous vinyl polymers as well as a number of methacrylate and acrylate type polymers and combinations of these polymers and related, film- forming polymers as described herein. The preferred primary film-former for use in the present invention is nitrocel¬ lulose.

Nitrocellulose for nail enamel compositions of the present invention is of two standard types designated respec¬ tively, RS and SS, also designated European Type E and M, respectively. Another type of nitrocellulose, AS nitrocel¬ lulose, is generally not used in nail enamels. RS nitrocel¬ lulose, available from a number of manufacturers including S.N.P.E. of Bergerac, France (as the equivalent Bergerac type) and Hercules Inc., of Philadelphia, Pennsylvania, USA, the preferred nitrocellulose for use in nail enamels, is available in a wide range of viscosities. Although a number of dif¬ ferent nitrocellulose film-formers may be used in composition of the present invention including RS 18-25 cp, RS 1/4 sec. and RS 5-6 sec, European Standard 33, 28 and 11, Bergerac E19, E20, E27 and E80, it is preferred that nitrocellulose RS 1/2 second, available from Hercules, be used in the composi¬ tions of the present invention. European Standard 22 and Bergerac E35 nitrocellulose may also be used in the present invention and in many aspects these nitrocellulose types may be substituted for nitrocelulose RS 1/2 second from Hercules. One of ordinary skill in the art will recognize that in for¬ mulating nail polish compositions according to the present

invention, different viscosities of nitrocellulose may be used, depending upon the viscosity and other characteristics of the final composition desired.

In general, the primary film-forming polymer is included in compositions of the present invention in amounts effective to provide toughness, hardness, resistance to abra _¬ sion, solvent release and a film thickness, in combination with secondary film-forming polymers and plasticizers. In general, the amount and type of primary film-forming polymer is chosen so that the nail enamel, after drying on a natural or synthetic nail will have a thickness of about 2.5 mil to ₆ mil, preferably about 3 mil after only one coat. While it is to be recognized that more than one coat of nail enamel may be used to coat nails according to the present invention, preferred compositions according to the present invention are compositions that provide acceptable characteristics includin film thickness after one coat.

In general, the amount of primary film-forming polyme comprises about 5% to about 25% by weight of the compositions, preferably about 7.0% to about 20% by weight of the composi¬ tions and most preferably about 10% to about 18% by weight of the composition.

In addition to the primary film-forming polymer, the compositions of the present invention also include a secondar film-forming polymer which is added to the primary film- forming polymer for its ability to provide strength, gloss. an adhesion. Exemplary secondary film-forming polymers which ma be used in the present invention include alkyd resins, polyvinyl resins, for example, polyvinyl acetate, polyester resins, acrylic and methacrylic resins and arylsulfona ide- formaldehyde resins, among others. Toluene sulfonamide- formaldehyde resin, a condensation product of formaldehyde a toluene sulfonamide (available as Ketjenflex MS-80 ^tltl from Ak Chemie America Chicago, Illinois) is especially preferred fo use as a secondary film-forming polymer in the present inven tion. In general, the amount of secondary film-forming

-20-

polymer used is that amount effective to strengthen the _. pri _¬ mary film-forming polymer and provide an effective gloss and adhesion. One of ordinary skill in the art will be able to determine the amount of secondary film-forming polymer which may be added to the compositions of the present invention to produce the desired effect without engaging in undue experimentation. However, in general, as a guideline, the amount of secondary film-forming polymer to be used in the present invention ranges from about 3.0% to about 13% by weight of the composition ^" , preferably about 5.0% to about 10 by weight and most preferably about 5.0 to about 7.0% by weight of the composition.

In addition to primary and secondary film-forming polymers, the compositions according to the present inventio also include at least one plasticizer. Plasticizers for use 5.n the present invention are added to soften and plasticize the primary film-forming polymer. The choice of plasticizer for a nail enamel composition may vary as a function of the color, odor, effect on viscosity of the enamel, effect on th drying rate, the amount needed to meet flexibility require¬ ments, the volatility of the plasticizer and compatability with the other components of the compositions. Plasticizers for use in the present invention include tricresyl phosphate diamylphthalate, dioctylphthalate, diphenylphthalate, dibutoxyphthalate, dibutyl phthalate, diethyl phthalate, dibutyl tartrate, benzyl benzoate, tributyl phosphate, butyl acetyl ricinoleate, butyl glycolate, butyl stearate, triphe phosphate, triethyl citrate, camphor, castor oil and di.buto ethylphthalate, among others. Preferred plasticizers for u in the present invention include dibutyl phthalate, camphor and especially mixtures of dibutyl phthalate and camphor. general, plasticizer is included in the compositions of the present invention in an amount sufficient to provide accep¬ table flexibility to nail enamel on the human or synthetic nail surface. By acceptable flexibility, we mean that the composition will evidence a substantial absence of cracking when a 6 mil film which has been dried on an aluminum strip surface for at least two hours is bent around a 0.25" mandr

(available from Gardner Corporation, Florida, USA). In gen _¬ eral, the amount of plasticizer for use in the compositions o the present invention ranges from about 2.0% to about 11. ₀ %, preferably about 2.0% to about 7.5% and most preferably about 3.0 to about 6.0% by weight. In cases where the primary film forming polymer or secondary film-forming polymer is instille with plasticizer-like characteristics or with an absence of these characteristics, the amount of plasticizer may vary below and above these ratios.

In addition to the primary and secondary film-forming polymers and plasticizer, the compositions according to the present invention include a solvent mixture containing acetone, and preferably a wetting agent and a diluent solven wherein the amount of acetone ranges from about 6.0% to abou 70% of the total weight of the solvent. Because the total amount of solvent ranges from about 50% to about 75% by weig of the nail enamel compositions of the present invention, acetone therefore comprises about 4.5% to about 35% by weigh of the total weight of the nail enamel compositions. The amount of acetone included in the compositions is selected t create an interaction with the other solvents that are used the compositions. It has surprisingly been found that aceto used in combination with the additional solvents of the sol¬ vent combination will result in a nail enamel composition which will dry in less than about three minutes. By "dry" w mean that the nail enamel compositions will evidence no tack with a cotton swab (Q-tiptm, available from Chesebrough- Pond's, Greenwich, Connecticut, USA) when drawn down on to a mil thick layer on lineta cards (Lineta Company, Hohokus, Ne Jersey) at room temperature and a relative humidity of about 50 to 55%. Of course, the drying time of a nail enamel for¬ mulation will vary to a certain degree as a function of the temperature and relative humidity of the ambient atmosphere.

Solvents other than acetone which may be used in th compositions of the present invention include, for example, wetting agents such as ethanol, ethanol, isopropanol and n butanol and various diluent solvents including amyl acetate

n-butyl acetate, methyl acetate, ethyl acetate, propyl acetate, methyl chloroform, methylene chloride, toluene and mixtures thereof, among others, including numerous ethers and alkanes including pentane, hexane, heptane and cyclohexane and mixtures thereof among others, in varying weight percentages. In addition to the above-named solvents, other solvents may be used in the present invention include, for example, cyclopentane, 1,4-dioxane, petroleum ether and tetrahydrofuran, including mixtures thereof, among others. High, boiling solvents, for example, cellosolve, butyl cel¬ losolve acetate, cellosolve acetate, methyl cellosolve acetate, butyl cellosolve, ethyl cellosolve and phenylated solvents including xylene may also be used. Individual wet¬ ting agents and diluent solvents may be ineffective alone for dissolving the primary film-forming polymer, secondary film- forming polymer and plasticizer or for producing the proper gelling effect when formulated in combination with an organoclay thixotropic agent.

Of course, the high-boiling solvents, i.e. those sol¬ vents having a boiling point greatly in excess of 100*C, have a tendency to increase drying times in certain compositions according to the present invention and therefore are included in weight percentages in amounts consistent with instilling the desired characteristics of the high boiling solvent and producing a nail compositionvwhich dries in less than three minutes. In certain cases, the amount of high boiling solvent may be included in an amount no greater than about 5.0%.and often in an amount less than about 5% by weight of the final composition. One of ordinary skill in the art will know to vary the weight percentages of acetone and the other solvents used in compositions of the present invention within the teachings of the present invention to produce a very large number of acceptable solvent combinations for use in nail enamel compositions which dry in a period of about three minutes or less.

In addition to acetone, the inclusion of methyl- chloroform -in compositions of the present invention in certain

cases may have a beneficial effect on the drying time. However, the effect of methylchloroform is not nearly as great as that produced by the disclosed weight percentages of acetone.

While not being limited by way of theory, it is believed that acetone is responsible for creating an interac¬ tion with the other solvents utilized in the present invention to substantially reduce the drying times of nail compositions to about three minutes or less. Such interaction may be due to the universality of solvency that acetone displays with almost any solvent. As noted, acetone is miscible with a very large number of different solvents which vary dramatically in solubility characteristics. It is quite surprising that a combination of solvents which, in combination with the non¬ volatile components of the present invention, normally do not dry within a period even close to three minutes, dries in a period less than about three minutes with the inclusion of the disclosed amounts of acetone. Even more surprising is the fact that the inclusion of at least about 18% by weight acetone in combination with other solvents will produce a pig¬ mented nail enamel composition containing thixotropic agent which will dry in about 60 seconds (in certain cases, in even less time) and a clear nail enamel composition containing an absence of pigment and thixotropic agent which dries in iess than 30 seconds.

The amount of acetone included within the composition according to the present invention varies between about 4.5% and about 35%. This range represents a guideline for inclu¬ sion of acetone in compositions according to the present invention to produce a nail enamel composition which dries in about three minutes or less. The lower limit of this range represents the least amount of acetone that is generally used to produce a nail enamel composition containing a thixotropic agent and pigment which dries in less than about three minutes. The upper limit of this range represents the amoun of acetone above which begins to produce an unacceptable streaking effect on the enamel during coating. In addition,

compositions containing more than about 35% acetone tend ^' to fall below acceptable viscosities. Compositions according to the present invention include an amount of acetone generally falling within this range, the amount of acetone to be included being determined by the desired drying time and the additional solvents which are added to produce the desired viscosity and flow characteristics.

In many of the commercial nail enamel preparations on the market, toluene, xylene or other aromatic solvent is included in varying amounts as a diluent, generally in com¬ bination with a wetting agent which tends to be isopropanol or ethanol. The use of toluene as a diluent is to provide accep¬ table viscosities and other characteristics. Where toluene is used, the amount of toluene may vary from less than about 1% to more than about 30% by weight of the nail enamel composi¬ tions of the present invention. In an additional aspect, the present invention also relates to quick-drying compositions which have acceptable characteristics and which exclude toluene and other aromatic solvents which may not be accep¬ table for inclusion in cosmetic formulations by regulatory agencies. In this aspect of the present invention, toluene or other aromatic solvent is replaced. ith another solvent, espe¬ cially for example, a ketόne-containing composition other than acetone such as methyl ethyl ketone or a related ketone, one of the esters of acetic acid such as ethyl acetate or methyl acetate, among others. In fact, through choice of solvents, it is possible to produce a nail enamel composition in which the solvent system is comprised of innocuous solvents. In addition, certain chlorinated hydrocarbons for example, methylchloroform, methylene chloride, chloroform and hydrocar bon solvents, for example, hexane, cyclohexane, cyclopentane, pentane and heptane, as well as numerous additional solvents such as ethers, among others, may be used to replace toluene and related aromatic solvents.

In compositions of the present invention which contai an absence of pigment and organoclay thixotropic agents, virtually any low boiling solvent, i.e., a solvent which has

boiling point less than about 90*C, may be substituted for toluene or other aromatic (containing a phenyl or substituted phenyl group) solvent provided that the primary film-forming polymer, secondary film-forming polymer and plasticizer are dissolved by the solvent combination. In compositions without thixotropic agent or pigment, numerous high boiling solvents may also be used, but care must be taken to limit the use of such solvents to low levels to avoid increasing the drying time to above acceptable limits. An acceptable drying time for compositions which contain an absence of pigment and/or thixotropic agent is less than 30 seconds at room temperature and a relative humidity of about 50-55%. In order to produce such a fast drying time, in this aspect of the present inven¬ tion, these nail enamel compositions, contain at least about 18% by weight acetone and preferably at least about 24% acetone. Following the guidelines and descriptions of the present application will enable one of ordinary skill in the art to readily substitute for toluene and still maintain the drying times within acceptable limits.

In compositions of the present invention which contai a pigment and an organoclay thixotropic agent, the choice of solvents which may substitute for the toluene or other aromatic diluent is more limited than those compositions con¬ taining an absence of thixotropic agent and pigment. In thes compositions, care must be taken to substitute a solvent which, in combination with acetone, and preferably, a wettin agent and a different diluent solvent, results in a solvent combination which dissolves the primary film-forming polymer, secondary film-forming polymer and plasticizer and produces gel in combination with the organoclay thixotropic agent. Care must be taken especially when choosing the amount and type of diluent solvent(s) to be used. In certain cases, th use of very large quantities of non-polar solvents, for exam ple, hydrocarbons such as hexane, heptane and pentane as wel as other non-polar solvents, without the inclusion of suffi¬ cient amounts of more polar solvents, may affect the ability of the organoclay thixotropic agent to form a gel, preferabl colloidal gel. In addition, the inclusion of large percen

agέs ^: of highly polar solvents, for example, methanol, ethanol and isopropanol in certain compositions may adversely affect the ability of the thixotropic agent to form a gel, preferabl a colloidal gel and compositions to maintain storage stabilit for any commerically viable period of time. In addition, vis cosities may be adversely affected. Therefore, as a guidelin and general rule for formulating compositions of the present invention, polar substitutes for toluene as the diluent sol¬ vent in this aspect of the present invention should be limite to no greater than about .25% by weight of the total weight of the composition and preferably substantially less than about 20% by weight of the composition. Obviously, the amount of polar substitute to be used as a substitute for toluene-will depend upon the type of solvent used, the relative polarity o the solvent and its effect on the gel of the present inven¬ tion.

Because the amount of wetting agent used in certain compositions according to the present invention may result in a negative impact on the viscosity and to a lesser extent, th drying time of the nail enamel formulations, care should be taken to minimize the use of these solvents. In addition, th amount of wetting agent may negatively impact the organoclay thixotropic agent and the gel formed by using such agents. Most preferably, and in many cases, the amount of wetting agent should be limited to less than about 5% by weight of nail enamel formulations.

Preferably, substitutes for toluene in this aspect o the present invention include esters of acetic acid, for exa ple methyl acetate, ethyl acetate, propyl acetate and n-buty acetate, ketones other than acetone, including methyl ethyl ketone, chlorinated hydrocarbons, for example, methylene chloride, chloroform and methylchloroform as well as other solvents of similar polarity to toluene. More and less pola diluents than those set forth above may also be used, but ca should be taken to choose the amount and type of diluent(s) based upon the amount of acetone and, in certain cases, wet¬ ting agent (both of which tend to be polar solvents) to be

inσluded in the compositions of the present invention.

In certain compositions according to the present invention, a pigment and an organoclay thixotropic agent is also added, generally to the suspension base during formula _¬ tion. Pigments are added to the compositions to provide cos etically acceptable shades and to opacify the films. Any number of pigments may be used in the present invention including for example, red pigments, including for example, & C red Nos. 10, 11, 12 and 13, D & C red No. 7, TOB-BON maroon (D & C red No. 34) . Other pigments which may be used in compositions according to the present invention include t Lake pigments, for example, D & C yellow No. 5 Lake, D & C R No. 2 Lake, and Ext. D & C Red No.2 Lake. In addition to th above-named pigments, additional pigments can include ^; cosmetic-grade or purified titanium dioxide (white) , yellow and red iron oxides, iron blue, iron black, ultramarine blue chromide oxide greens, carbon black or lampblack (generally, in minute quantities), among others. Although the amount of pigment in compositions of the present invention will vary a a function of the type of pigment and other components included in the compositions, in general, pigments are included in an amount up. to about 6.0% by weight of the com position, generally from ^' about 0.025 to about 4.0% by weigh and preferably in an amount ranging from about 0.5 to about 2.5% by weight of the composition.

In addition to or in place of certain of the above- described pigments, iridescent or pearlizing pigments or agents may be included in the compositions of the present invention, for example, "pearl essence", which is a suspens of crystalline guanine ("needle type" or "plate type") in nitrocellulose and solvents as well as other pearlizing agents. These pearlizing agents may be included for their individual appearance, their effect on the appearance of ot pigments and their positive effect on wear and stability, especially adherence and resistance to shock (See, for exam ple, DuFour, French Patent No. 1,461,812). In addition to guanine, other pearlizing agents which can be used in the

piresent invention include, for example, bismuth oxychloride, titanium dioxide (also classified as a white pigment) and mica, in weight ratios readily within the teachings of the prior art, and generally, about 0.025% to about 4.0% by weigh of the nail enamel compositions. The amount of pearlizing additive or pigment included in the compositions according to the present invention is not expected to substantially affect the drying times, viscosities or most other characteristics o the compositions within the concept of the present invention. Of course, it will be understood that in certain compositions which include certain pigments and/or pearlizing additives, the various components used to produce nail enamel formula¬ tions including the amount of acetone and other solvents used may have to be modified to produce commercially acceptable nail enamel formulations having advantageous drying times, viscosities and wear characteristics.

When pigments are included in compositions according to the present invention, it is generally advantageous to include an organoclay thixotropic agent for enhancing the suspension of pigment in the other components of the composi tion. A number of organoclay thixotropic agents used in the nail enamel art may be used to produce compositions accordin to the present invention, including for example, bentonite, generally sodium bentonite and calcium bentonite, montmoril- lonite clay, which is generally a key component of bentonite hectorites, which are trioctahedral hydrated silicate of mag nesium and lithium of the montmorillonite group of clays having the general formula (Mg,Li)3Si40 _lu (0H)2 and smectite. Which are dioctahedral and trioctahedral clay minerals (mont morillonite and saponite) and their chemical varieties which are preferably modified with quaternary ammonium compounds, for example as described in Remz, Cosmetics & Toiletries. 10 70 (December, 1988). Preferred organoclay thixotropic agent for use in the present invention include the hectorite clays modified with quaternary ammonium compounds as described above, especially including the stearalkonium hectorites.

Particularly preferred hectorites for use in the pr

ent invention include the Bentones ^tn », such as Bentone ²⁷ avail able from NL Industries, New Jersey, USA, especially the stearalkonium hectorites. An especially preferred stearalkonium hectorite thixotropic agent for use in the pres ent invention is Bentone RSNC ^tm , available from Penn _C olor, Doylestown, Pennsylvania USA. Bentone RSNC ^tm is a compositio containing about 25% by weight stearalkonium hectorite milled to about 5 microns in nitrocellulose and plasticizer (camphor) . In particularly preferred compositions according to the present invention, a thixotropic agent is included in an amount sufficient to produce a gel, preferably a colloidal gel. in general, the organoclay thixotropic agent is include in the compositions of the present invention in amounts suffi cient to produce a colloidal gel, usually from about 0.5% to about 5% by weight of the composition, preferably about 0.5% to about 2.0% and most preferably about 1% to about 1.5% by weight of the composition.

The use of a preferred thixotropic agent, stearalkoniumhectorite, and especially Bentone RSNC ^tm in com¬ positions according to the present invention results in a gel which serves to suspend the pigment and maintain the pigment in suspension for extended periods of storage. The thixotropic agents which are used in the present invention a generally combined with pigment and a sufficiently polar sol vent mixture containing sufficient quantities of acetone, an preferably, a wetting agent and a diluent solvent(s) in com¬ bination with primary film-forming polymer and secondary fil forming polymer and mixed under shearing force (Hoffmeyer industrial mixer generally for a period of at least one hour preferably two hours) . In this aspect of the present inven- tion, certain highly preferred compositions according to the present invention which include a Bentone ^tτn , especially, for example, Bentone ²⁷ or Bentone RSNC ^tm in sufficient quantity to produce a gel are storage stable, i.e., they maintain the viscosity, consistency and pigment in suspension without th need for significant shaking even after extended periods of storage.

SUBSTITUTESHEET

It is important to note that the acetone-containing solvent mixtures chosen for use in compositions according to the present invention which contain stearalkonium hectorite should be of sufficient polarity to favorably interact with this thixotropic agent to produce a gel upon standing after being mixed under shearing force. The gel which is produced in preferred embodiments of the present invention results in suspension of pigment which will not settle to the same exten as nail enamel compositions which do not contain such a gel suspension. The compositions of the present invention which utilize stearalkonium hectorite thixotropic agents are there- fore storage stable and may be applied to the nail even after periods of long storage by a simple shaking of the container before application. In many cases there is no need to inclu for example, a steel ball to enable a vigorous shaking, of th composition before application as is required by many of the compositions of the prior art.

In addition to the above-described components, the cpmpositions of the present invention may also include addi¬ tional additives including stabilizers, preservatives, anti- pxidants, fragrances, UV absorbers, levelling agents and oth additives, depending upon the desired result. These com¬ ponents are well known in the art and may be included in amounts well within the teachings of the art.

SUBSTITUTE SHEET

The nail enamel compositions of the present invention have characteristics of quick-drying, flexibility, durability, adequate viscosity and high gloss. The pigmented compositions of the present invention dry in a period of less than about three minutes. By "dry" we mean that the compositions will evidence a substantial absence of tack (absence of smudging ₎ after a three minute drying period at room temperature and a relative humidity of about 50-55%. Compositions of the pres¬ ent invention are also flexible, i.e., the composition will evidence a substantial absence of cracking when a 6 mil film which has been dried on an aluminum strip surface for at least about two hours is bent around a 0.25" mandrel (available from Gardner Corporation, Florida, USA) . Compositions of the pres¬ ent invention are also durable and do not appreciably chip or crack for a period of at least about three days of wearing on a human or synthetic nail.

The viscosities of compositions of the present inven¬ tion are commercially acceptable. In general, as previously indicated, the static viscosities of the compositions of the present invention which include an organoclay thixotropic agent generally fall within the range of about 400 to about 1200 centipoises, preferably about 800 centipoises. In certain cases, the viscosities of the compositions may fall outside these ranges. For purposes of defining the present invention, static viscosities are determined on a Brookfield RVF viscometer after at least 24 hours of incubation at 25*C using a spindle #3 at 25 ^* C and 20 RPM. In addition to static viscosities, shaken viscosities of the compositions according to the present invention are also generally commerically acceptable. Shaken viscosities differ from static viscosities and are determined in the following two ways. First, shaken viscosities are determined using a Brookfield LVF viscometer, spindle #3 at 60 RPM after the compositions are shaken for a brief period. The compositions of the present invention exhibit a shaken viscosity under these conditions generally ranging from about 200 to about 500 centipoises, with an ^" optimum of about 400 centipoises. Additional shaken vis¬ cosities are determined at 6 RPM on a Brookfield LVF vis-

cbmeter, spindle #3 at 25 ^β C. Viscosities of the compositions of the present invention under these conditions generally range from about 800 to about 1200 centipoises, with an optimum of about 1000 centipoises.

Compositions of the present invention generally exhibit an acceptable gloss ranging from about 70 to about 95% reflection of light as determined by a Glossguard Meter (6 mil thick coating on an aluminum surface) . Preferably, the com¬ positions of the present invention exhibit a gloss ranging from about 85 to about 95% reflection of light as determined by a Glossguard Meter.

The present invention also relates to a nail prepara¬ tion kit comprising a polymer base containing an organoclay thixotropic agent adapted for drying and hardening to form a pigmented coating on a nail upon mixture of the base with a suitable solvent mixture, the solvent mixture comprising an amount of acetone comprising at least about 4.5% to about 35% by weight of the final nail enamel composition including solids in combination with a wetting agent and a solvent diluent to produce solvent combinations which dissolve the primary film-forming polymer, the secondary film-forming . polymer and the plasticizer and gel the organoclay thixotropic agent, the composition having a final static viscosity ranging from about 400 to about.1200 centipoises, preferably about 800 centipoises. In addition to primary film-forming polymer, secondary film-forming polymer, plasticizer and thixotropic agent, the polymer base additionally comprises at least one pigment and optionally, additional additives including pre¬ servatives and fragrances, among others. In this nail preparation kit aspect of the present invention, the polymer base comprises about 25% to about 50% by weight of the final nail enamel composition to be applied to the nail and the sol¬ vents comprise about 50% to about 75% by weight of the com¬ position, preferably about ^' 60% to about 70% by weight and most preferably about 64% to about 69% by weight solvent. The nail preparation kit aspect of the present invention also includes top coat, basecoat and clear nail enamel compositions which

contain at least about 18% to about 35% by weight acetone, preferably at least about 24% to about 35% by weight acetone in combination with a primary film-forming polymer, a secondary film-forming polymer, a plasticizer and an absence of pigment and thixotropic agent. These compositions dry in period of time no greater than about 30 seconds.

To use the nail preparation kit of the present inven¬ tion, the user will add the solvent mixture to the base for¬ mula which contains primary film-forming polymer, secondary film-forming polymer and plasticizer. After thoroughly mixin the solvent with the three solid ingredients, the resulting mixture may be used as a clear basecoat, top coat, or nail enamel. Alternatively, if a pigmented nail enamel compositio is desired, after thorough mixing of the solvent, primary film-forming polymer, secondary film-forming polymer and plasticizer, an organoclay thixotropic agent is added and the mixture vigorously shaken or otherwise mixed (generally under shearing forces) for a period of time sufficient to produce a homogeneous mixture. Thereafter, pigment is introduced into the mixture and the pigment-containing mixture is thoroughly mixed until a homogeneous. ixture is realized. The final product may then be stored or coated onto a natural or synthetic nail surface.

In still another aspect of the present invention, so vent mixtures particularly adapted for use in combination wi pigmented polymer bases for use in nail enamel compositions are also disclosed. In this aspect of the present invention a- solvent mixture comprises acetone in an amount equal to about 6% to about 70% by weight of the solvent mixture, and preferably a wetting agent and a diluent solvent to produce solvent mixture which, in combination with a polymer base adapted for use in nail enamel preparations comprising a pri mary film-forming polymer, a secondary film-forming polymer, at least one plasticizer, an organoclay thixotropic agent an pigment, provides a gelled nail enamel preparation containin at least about 4.5% to about 35% by weight acetone and which has a static viscosity ranging from about 400 to about 1200

centipoises and drying in a period less than about three minutes to a hard, flexible pigmented surface having accep _¬ table wear characteristics including durability an _d hig _h gloss. Solvent systems for use in basecoat, top coat an _d clear enamel compositions without pigment and organoclay thixotropic agents contain at least about 24% by weight acetone up to about 70% by weight acetone.

The present invention also relates to methods of making and using the compositions of the present invention. In this aspect of the present invention nail enamel composi¬ tions of the present invention are formulated by first mixing a number of solvents including an amount of acetone equal to about 6% to about 70% by weight of the solvent mixture to pro¬ duce a solvent mixture. Thereafter, a primary film-forming polymer, a secondary film-forming polymer and at least one plasticizer is added step-wise in any order in conjunction with vigorous mixing until a viscous solution is produced. The compositions produced according to this method can be used as colorless nail polishes or alternatively, as base coat and top coat formulations in conjunction with colored nail polishes. After the viscous solution is produced, an organoclay thixotropic agent, for example, stearalkonium ^" hec¬ torite, is added to the above-described mixture in conjunction with vigorous stirring (under strong shearing force with a Hoffmeyer industrial mixer) generally for a period of about at least one hour to produce a gelled mixture. In the last step, one or more pigments are added to the above gelled mixture to produce the rapid drying mixtures according to the present invention. The final composition produced by the method according to the present invention obtains a final static vis cosity ranging from about 400 to about 1200 centipoises. Certain compositions of the present invention produced in thi Way including Bentone RSNC^™ and/or Bentone ²⁷ are storage stable and do not require the vigorous shaking that the prior art compositions often require after extended periods of storage. The compositions of the present invention are used by simply applying the composition to the surface of a natura or synthetic nail. SUBSTITUTE SHEET

The following examples are provided to illustrate the present invention and should not be construed to limit the scope of the invention of the present application in any way.

EXAMPLE 1

To demonstrate the effectiveness of the solvent com¬ positions of the present invention in speeding the rate of drying of nail enamels, a commercially available red nail enamel sold under the trademark L'OREAL "Drumbeat" was obtained and the solvents distilled therefrom. The solvents were replaced by a solvent system containing 28.28 percent acetone in combination with additional solvents, including methylchloroform, ethyl acetate, toluene, butyl acetate and isopropanol in the following weight ratios:

Results: The L'Oreal product "drumbeat" was evaporated o near dryness and the solvent system including 17.68% by weight acetone was added to the solids remaining after evaporation. The resulting suspension was shaken vigorously until a homogeneous suspension was realized. The viscosity was slightly thin, too thin to be commercialized. The drying time of the nail polish formulation was 70 seconds on plate glass. In comparison, the drying time of the L'Oreal product was greater than 4 minutes.

SUBSTITUTE SHEET

Examples 2-10

In the following examples, a number of solvent com¬ binations containing about 4.5% to about 35% by weight of acetone were used to produce a number of nail enamel composi¬ tions using a standard base formulation. In each case, the drying time of the formulations are about 3 minutes or less at about room temperature and a relative humidity of 50-55%.

Non-Volatile Component (Solids)

Component Weight Percent of

Final Composition

Primary Film-Forming Polymer 10.5%

Nitrocellulose RS 1/2 Sec. (From Hercules, Inc.)

Secondary Film-Forming Polymer 9.0

Toluenesulfonamide formaldehyde Resin (Ketjenflex MS-80 ^tm From Akzo Chemie)

Plasticizer

Camphor 0.4%

Dibutylphthalate 4.1e ^" .

Bentone RSNC ^tm 12.0%

Stearalkonium hectorite (25.5%) Nitrocellulose (60.5%) Camphor (14%)

Procedure: To produce nail enamel compositions, the com¬ ponents listed above were added step-wise, in the order 1) primary film-forming polymer; 2) secondary film-forming polymer and 3) plasticizer to the below-described solvent systems. Each component was added and mixed until a homogeneous solution was produced. After the first three com ponents were added, the Bentone RSNC ^tm was added and the resulting mixture was mixed under high shearing force with a laboratory mixer for at least about 1 hour until a homogeneo gel was obtained. Pigments are added with further mixing. The resulting compositions were then "drawn down" on lineta cards to determine drying times. Drying times were determin by placing a cotton swab (Q-tips from Cheseborough Ponds, US on the surface. An absence of sticking of cotton swabs to t

SUBSTITUTES

film was considered dry for purposes of the present invention. The drying times of the individual experiments are presented as indicated.

All formulations evidenced acceptable viscosities and an absence of streaking. To determine static viscosities, compositions were allowed to stand for at least 24 hours in a constant temperature bath at 25'C. Static viscosity tests were performed using a Brookfield LVF, spindle #3 at 12 RPM and 25"C. To determine static viscosity the dial reading was multiplied by a factor to. determine approximate viscosity (e.g., 8 X 100 = 800 cps) . It should be noted that the . static viscosities were determined in the following experi¬ ments with a Brookfield LVF, spindle #3, but are defined in the general invention using a Brookfield RVF, spindle #3 as those of ordinary skill in the art would define them. Because access to a Brookfield RVF was not available, the static vis¬ cosities in the following invention are presented using the available Brookfield LVF instrumentation. The compositions of the present invention have acceptable viscosities.

Shaken viscosities were determined on a Brookfield LVF using Spindle |3 at 25'C ^' a) at 60 RPM. To determine viscosity dial reading wa multiplied by a factor to determine approximate viscosity (e.g., 20 X 20 = 400 cps). b) at 6 RPM. To determine viscosity dial reading was multiplied by a factor to determine approximate viscosity (e.g., 5 X 200 = 1000 cps).

Because of the nature of the viscosity determination, and the fact that these determinations may depend upon the amount of shaking done (variable) , shaken viscosities are believed to be less reliable than are the static viscosities.

SUBSTITUTESHEET

Example 2

Solvent System #1

Solvent Percent By Weight of

Final Composition

Acetone 18.1%

Isopropanol 1.28

Ethyl Acetate 25.54%

N-Butyl Acetate 0.64

Methylchloroform 18.44

Results: Composition including solids was formulated as described above using 64% by weight of solvent system #1 and 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature of 68.4 ^β F (20.2"C) and a relative humidity of about 40% was 51 seconds. Drying time in a relative humidity of about 50-55% is less than 90 seconds. Static viscosity of the formulation was 1201 cps. Shaken viscosity at 60 RPM was 504 cps and at 6 RPM was 600 cps. Pigments are added without significantly affecting drying time.

Example 3

Solvent System #2

Solvent Percent By Weight of

Final Composition

Isopropanol 1.28

Ethyl Acetate 25.54%

N-Butyl Acetate 18.75%

Methylchloroform 18.44

Results: Absence of acetone to determine effect of acetone drying times. Composition including solids were formulated a described above using 64% by weight of solvent system #2 and 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature of 68.4 ^β F (20.2 ^β C) and a relative humidity of about 40% was 3 minutes and 17 seconds. Drying time in a relative humidity of about 50-55% is about 4.0 to 5.0 minute Static viscosity of the formulation was 970 cps. Shaken vis

-39-

cosity at 60 RPM was 626 cps and at 6 RPM was 720 cps. Pig¬ ments are added without significantly affecting drying time.

Example 4

Solvent System #3

Solvent Percent By Weight of Final Composition

Isopropanol 1.28 Ethyl Acetate 43.96% N-Butyl Acetate 18.75%

Results: Absence of acetone and methylchloroform to determi effect of acetone and methylchloroform on drying times.. Co position including solids were formulated as described above using 64% by weight of solvent system #3 and 36% by weight Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature of 68.4"F (20.2 ^β C) and a relative humidity of about 40% was 3 minutes and 9 seconds. Drying time in a relative humidity about 50-55% is about 4 to 5 minutes. Static viscosity of formulation was 1950. Shaken viscosity at 60 RPM was 700 c and at 6 RPM was 740 cps.

Example 5

Solvent System #4

_S olvent Percent By Weight of

Final Composition

Acetone 18.11?

Isopropanol 1.28

Ethyl Acetate 25.54% N-Butyl Acetate 0.51%

Methylchloroform 0.13%

Methylene Chloride 18.43%

SUBSTITUTE SHEET

Results: Experiment to replace toluene with methylene chloride. Composition including solids were formulated as described above using 64% by weight of solvent system #4- and 36% by weight of Non-Volatile Component as described above. Viscosities were in acceptable range. Drying time on lineta cards (3 mm draw down) at an ambient temperature of 70"F- (21.5 ^β C) and a relative humidity of about 50% was 64 seconds. Static viscosity of the formulation was about 1650 cps. Shaken viscosity at 60 RPM was.936 cps and at 6 RPM was 2000 cps. Pigments are added as desired without significantly affecting drying time.

Example 6

Solvent System #5

Solvent Percent By Weight of

Final Composition

Acetone 18.11%

Isopropanol 1.28

Ethyl Acetate 25.54%

N-Butyl Acetate 0.51%

Methylchloroform 0.13%

Methylethyl ketone 18.43%

Results: Experiment to replace toluene with methylethyl ketone. Composition including solids were formulated as described above using 64% by weight of solvent system #5 and 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature of 70"F (21.5 ^β C) and a relative humidity of about 50% was 79 seconds. Static viscosity of the formulation was 1470 cps. Shaken viscosity at 60 RPM was 624 cps and at 6 RP was 1120 cps. Pigments are added as desired.

SUBSTITUTE ^S HEET

Example 7

Solvent System #6 Percent By Weight of

Final Composition

Acetone 18.11%

Isopropanol 1.28

Ethyl Acetate 25.54%

N-Butyl Acetate 0.51%

Methylchloroform 0.13%

Hexane 18.43%

Results: Experiment to replace toluene with hexane. Composi¬ tion including solids were formulated as described above using 64% by weight of solvent system #6 and 36% by weight of Non- Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature of 70*F (21.5 ^β C) and a relative humidity of about 50% was 77 seconds. Static viscosity of the formulation was 930 cps. Shaken vis¬ cosity at 60 RPM was 710 cps and at 6 RPM was 300 cps. Pig¬ ments are added as desired without significantly affecting drying time.

Example 8 ve t S stem l

SUBSTITUTE SHEET

-42-

Results: Experiment to replace toluene with cyclohexane. Composition including solids were formulated as described above using 64% by weight of solvent system #7 and 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient tempera _¬ ture of 70 ^β F. (2l.5 ^* C) and a relative humidity of about 50% was 79 seconds. Static viscosity of the formulation was 1120 cps. Shaken viscosity was 704 cps at 60 RPM and 400 cps at 6 RPM. Pigments are added as desired. Inclusion of pigment does not significantly affect drying time.

Example 9

Solvent System #8

Solvent Percent By Weight of Final Composition

Acetone ^■ 4.5% Isopropanol 1.6 Ethyl Acetate 33.16% Toluene 23.95%

N-Butyl Acetate 0.66% Methylchloroform 0.13%

Results: Experiment to determine effect of reduced acetone. Composition including solids were formulated as described above using 64% by weight of solvent system #8 and 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient tempera- ture of 72.0°F (23.0 ^β C) and a relative humidity of about 24% was 2 minutes. Drying time in a relative humidity of about 50-55% is about 3 minutes. Pigments are added as desired without appreciably affecting the drying time.

SUBSTITUTE SHEET

-43-

Example 10

Solvent System #9

Solvent Percent By Weight of

Final Composition

Isopropanol 1.3

Ethyl Acetate 25.5%

Toluene 18.4%

N-Butyl Acetate 0.5%

Methylchloroform 0.1%

Methylene chloride 18.2

Results: Experiment to determine effect of replacement of acetone with a solvent, methylene chloride, that has a much lower boiling point than acetone. Experiment was performe to determine if interaction of lower boiling solvents with other solvents in mixture was responsible for fast drying times. Composition including solids was formulated as _d escribed above using 64% by weight of solvent system #9 an 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature o _f 64"F (17.8*C) and a relative humidity of abo ₃ 7% was ₃ minutes and 21 seconds. Drying time in a relativ humidity of about 50-55% is about 4.0 to 5.0 minutes.

SUBSTITUTESHEET

Example 11

Solvent System #10

Solvent Percent By Weight of Final Composition

Acetone 18.2 Isopropanol 1.3 Ethyl Acetate 25.5% Toluene 18.4%

N-Butyl Acetate 0.5% Methylchloroform 0.1%

Results: Composition including solids are formulated as described above using 64% by weight of solvent system #10 and 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature of 72.7"F (23.3 ^β C) and a relative humidity of about 55% is less than 60 seconds. Pigments are added as desired. Addition of pigment does not significantly affect the drying time.

Example 12

Solvent System #11

Solvent Percent By Weight of

Final Composition

Acetone 15.0

Isopropanol 1.3

Ethyl Acetate 25.5%

Toiuene 21.7%

N-Butyl Acetate 0.5%

Results: Composition including solids was formulated as described above using 64% by weight of solvent system #10 ^" and 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature of 68°F (21.7 ^β C) and a relative humidity of about

40% was about 1 minute 44 seconds. Pigments are added as desired. Addition of pigment does not significantly affect the drying time. Static viscosities were between 700 and 800 centipoises. Shaken viscosities were between 600 and 900 centipoises.

Example 13

Solvent System #12

Solvent Percent By Weight of Final Composition

Acetone 35.0 isopropanol 0 (In Nitrocellulose) Ethyl Acetate 13.3% Toluene 10.0% N-Butyl Acetate 0.5%

Non-volatile _Percent By Weight of Final Composition

Nitrocellulose 1/2 Sec. 21.0

(Hercules, Inc.) Toluene Sulfonamide Resin 9.0

(MS-80 ^tm ) Camphor 2.1

Dibutyl phthallate 4.1 Bentone 27 ^tm 5.0

Results: Composition including solids was formulated as described above using 64% by weight of solvent system #12 and 36% by weight of Non-Volatile Component as described above. Drying time on lineta cards (3 mm draw down) at an ambient temperature.of 68*F (21.7 ^* C) and a relative humidity of about 40% is about 1 minute 16 seconds. Addition of pigment does not significantly affect the drying time. Granular surface texture, but useable. Static viscosities were between 900 an 1500 centipoises. Shaken viscosities were between 700 and 1200 centipoises. High concentration of Bentone 27 ^tιn (5.0%) could be reduced substantially to provide lower viscosities. Pigments are added without substantially affecting drying times or other characteristics of product.

SUBSTITUTESHEET

Example 14

Nail Polish Formulation

In this example, a number of components are first prepared for later combination into a finished formula. First, the following two solvent blends were prepared:

Solvent Blend A

Solvent Percent By Weight of Blend

Acetone 28.3%

Isopropyl Alcohol 2.0% Ethyl Acetate 39.9% Toluene 28.8% N-butyl acetate 1.0%

Solvent Blend B

Solvent Percent By Weight of Blend

Ethyl acetate 44 . 0% N-butyl acetate 13 . 0% Toluene 43 . 0%

From the above-listed solvent blends A and B, a.color solution and Bentone-containing.suspending paste were prepared from the following components:

Color Solution C

Component Percent Bv Weight of Blend

D & C Red #7 color Chip 10.0%

Titanium Dioxide Chip 5.0%

Solvent Blend A 85.0%

The color chips (available from Penn Color, Inc., Doylestown, Pennsylvania) and solvent blend were combined and mixed at high speed with a laboratory cowles dissolver for approximately ten minutes. A smooth, particle free solution resulted.

A pigment suspending paste was prepared from the fol¬ lowing components:

Pigment Suspending Paste D

Component Percent By Weight of Blend

Bentone ²⁷ 10.0%

Solvent Blend B 90.0%

The above two components were combined and blended using very high shearing explosion proof Waring ^tm Blender for

-47-

five minutes resulting in a smooth, high viscosity paste.

A nitrocellulose-containing solution was prepared fr the following components:

Nitrocellulose Solution E

Component Percent By Weight of Blend

Nitrocellulose 1/2 Second R.S. 35% from Hercules, Philadelphia, PA.

Solvent Blend A 65%

The above components were combined using the laboratory cowles dissolver as the mixing device. A smooth uniform, clear lacquer was obtained from the above mixture.

A sample of red Fast Dryinq nail enamel was prepared from the above-described components as follows:

Component Percent By Weight of Enamel

Nitrocellulose Solution E 51.45%

Bentone ²⁷ Paste D 10.0%

Camphor 3.09%

Dibutyl Phthalate 6.77%

Color Solution C 15.00%

Toluene Sulfonamide Resin 5.20%

Acetone 8.49%

The above components were combined using the laboratory cowles dissolver as the mixing device to produce sample of Red Fast Drying nail enamel acceptable as a comme cial preparation.

The red Fast Drying nail enamel contains the following com¬ ponents:

Component Percent By Weight of Ename

Nitrocellulose 1/2 second R.S. 17.87%

(Hercules)

Isopropyl Alcohol 0.925%

Acetone 21.58%

N-butyl acetate 1.63%

Toluene 17.18%

Ethyl acetate 22.41%

Bentone ²⁷ 1.0%

Camphor 3.09%

Dibutyl Phthalate 6.77 ~ ^" .

D.S C. Red 7 Chip 1.50

(35% Pigment, 17% DiButylphthalate,

^' 48% Nitrocellulose)

Titanium Dioxide Chip 0.75

(71% Pigment, 7% Camphor, 22% Nitrocellulose) Toluene Sulfonamide Resin 5.20%

The above, formula yielded a very attractive red nail enamel with good gloss. It has a very fast drying time of about two minutes or less utilizing the previously described method for determining drying time. A panel was conducted and 10 panelists were chosen to wear the formula. They found the above quick drying nail enamel to be a very satisfactory prod¬ uct with an exceptionally fast drying time relative to commer¬ cially available products.

Example 15

Composition Containing 15% by Weight Acetone

Following the methodology used for producing the com¬ position in examples 1-13, a nail enamel composition contain¬ ing the final weight percentages of the example 14 components was produced. In the following example, the acetone of 21.58% by weight was reduced to about 15% by weight making up the loss with toluene (the highest boiling solvent in the mix¬ ture) . The pigmented chips from Example 12 were replaced with nitrocellulose 1/2 Sec. (Hercules, Inc., Philadelphia, Pa.) and Bentone RSNC ^tm . Solvent Component Percent Bv Weight

Acetone 15.0%

Isopropyl Alcohol (IPA) 0.9% n-Butyl Acetate 1.6%

Ethyl Acetate 22.4

Toluene 23.8%

Non-Volatile Component Percent Bv Weight

Nitrocellulose 1/2 Sec. 19.15

(Hercules, Inc.) Bentone 27 ^tm 0.75

Bentone RSNC ^tm . 1.00

(Contains Camphor and Nitrocellulose) Camphor 3.20

Dibutyl Phthallate 7.00

Toluene Sulfonamide 5.20

Formaldehyde Resin (Ketjenflex MS-80 ^tm )

The above formula yielded static viscosities of 300-

400 centipoises. It had a drying time of 2 minutes 36 secon at.68 degrees and approximately 40% relative humidity using the previously described method for determining drying time. Pigments are added to produce attractive nail enamels having favorable characteristics.

Example 16

Base Coat/Top Coat Composition

Component Percent Bv Weight

Nitrocellulose RS 1/2 Sec. 8.2

(Hercules, Inc.)

Toluene Sulfonamide Formaldehyde 3.5

(Ketjenflex MS-80 ^tm )

Camphor 1.50

Dibutyl Phthallate 2.0

Acetone 18.0 Isopropyl Alcohol 3.8

Ethyl Acetate 57.0 n-Butyl acetate 1.4

Toluene 4.6

The above formula is made by the method described fo Examples 2-13, above by adding the non-volatile components step-wise to the solvent mixture. The formula has a very fa drying time of less than about 30 seconds at room temperatur and a relative humidity of 50-55% using the previously described method for determining drying time. This formula makes an acceptable base coat/top coat formulation for use alone or with pigmented formulations including those describ in the present invention.

Example 17 Base Coat/Top Coat Composition

Component

Nitrocellulose RS 1/2 Sec.

(Hercules, Inc.) Toluene Sulfonamide Formaldehyde

• (Ketjenflex MS-80 ^tm ) Camphor

Dibutyl Phthallate Acetone

Isopropyl Alcohol Ethyl Acetate n-Butyl acetate Toluene

The above formula is made by the method described f

Examples 2-13, above by adding the non-volatile components step-wise to the solvent mixture. The formula has a very fast drying time of less than 30 seconds at room temperature and a relative humidity. of 50-55% using the previously described method for determining drying time. This formula makes an acάeptable base coat/top coat formulation for use alone or with pigmented formulations including those described in the present invention.

Example 18

Base Coat/Top Coat Composition

Component Percent Bv Weight

Nitrocellulose RS 1/2 Sec. 8.2

(Hercules, Inc.)

Toluene Sulfonamide Formaldehyde 3.5

(Ketjenflex MS-80 ^tm )

Camphor 1.50

Dibutyl Phthallate 2.0

Acetone 35.0

Isopropyl Alcohol 3.8

Ethyl Acetate 40.0 r_τ-Butyl acetate 1.4

Toluene 4.6

^'■ The above formula is made by the method described for

Examples 2-13, above by adding the.non-volatile components step-wise to the solvent mixture. The formula has a very fast drying time of less than 30 seconds at room temperature and a relative humidity of 50-55% using the previously described method for determining drying time. This formula makes an acceptable base coat/top coat formulation for use alone or with" pigmented formulations including those described in the present invention.

This invention has been described in terms of specific embodiments set forth in detail herein, but it should be understood that these are by way of illustration and the invention is not necesarily limited thereto. Modifications and variations will be apparent from the disclosure and may be resorted to without departing from the spirit of the inven¬ tions those of skill in the art will readily understand. Accordingly, such variations and modifications are considered

to be within the purview and scope of the invention and the following claims.

SUBSTITUTESHEET