The present invention relates to a composition for coating a nail according to the preamble of claim 1. The invention further relates to a combination of compositions according to claim. 23. The invention also relates to a method for providing a conductive layer to a nail according to claims 20 and 21 and to the use ac ^¬ cording to claim 26.

Such composition is known in the art. For example, a nail polish is commonly known. Nail polish is available in a number of varieties, for example as a single layer lacquer or a multilayer lcquer, comprised of at least two of a base coat, a colour coat and a top coat. Among others, solvent based nail polish is known, the solvent being removed from the applied composition by evaporation, such that a solid layer is obtained. Also, nail polish based on curable components are known, like monomers, dimers, trimers and oligomers. These products are commonly identified as "gel nails" and "shellac nails". The present invention is directed to these types of nail polish, hereinafter identified as "gelnail polish". Curing may be obtained by means of polymerisation. A commonly used method is curing using UV radiation, but crosslinkers present in the composition may be used as well. It has shown that especially people wearing long nails, the length being such that the nail protrudes beyond the finger tip, use nail polish.

Within the present invention the term "nail" relates to both a natural nail and an artificial nail. The compositions applied according to the present invention should be compatible with at least one of the nail and the artificial nail.

It is known in the art, especially when using polymeri sable compositions, to pretreat the natural nail by roughening the nail and subsequently applying a primer. The primer is covered with a base coat, forming part of the nail polish-formulation, with a coloring layer and an, optional, top layer. The coloring layer is applied for providing colour to the nail, whereas the top coat provides a long lasting a shiny finish. The base coat may also comprise a coloring agent, such that a separate coloring layer is not required. Furthermore, the top layer may be omitted. Traditional nail polish, based on an evaporating solvent, may usually be applied as a single layer, although the application of a plurality of layers is possible as well.

Known nail polish compositions have a common disadvantage, in that they are not suitable for operating a touch screen (a screen that is operated by a user touching the screen with his/her fin- gertips). An additional disadvantage is that people wearing long nails may not touch the screen with their fingertips, since opera ^¬ tion of a touch screen with a natural nail is not possible and the natural nail prohibits contacting the screen with one's finger tips. Such screens cannot be operated with a nail; the screen does not recognize the touch of a nail or is not sufficiently accurate.

So as to enable users of nail polish to operate a touch screen, so-called finger gloves have been provided and that contain a conductive material. These finger gloves however, have the disadvantage that they easily get lost, are removed from the fin- ger tips or yield irritation.

Furthermore, Korean patent application KR 101126101 mentions that an electrically conductive nail polish may be obtained by in ^¬ corporating a metal or a metal oxide in the nail polish. A disad ^¬ vantage, however, of said nail polish is that the polish is not stable. The nail polish has a short life time since the metals chemically interact with oxygen or other components present in the nail polish and a a consequence change colour of said polish. It has also shown that, after application of said polish to a nail, interaction with oxygen in the air may change the polish' colour. On the other hand, encapsulation of the metal particles may reduce conductivity. These nail polish also demonstrate a high tendency to agglomerate. After a short time, the particles settle. Furthermore, the metals used have the disadvantage that they are detrimental to the skin and/or are to be treated as chemical waste, such reducing the applicability.

A separate electrically conductive touch pen may be used, for example a pen to be stored in the head phone output of the appa- ratus to be operated, so as to store said pen. However, such pen may easily get lost. However, then the pen also blocks the head phone output. These aspects all have the consequence that a user of nail polish or a person wearing long nails is not capable to operate a touch screen.

The invention aims at providing a solution for at least one of the problems mentioned above.

The invention especially aims at providing a solution that enables one to operate a touch screen even when wearing long nails, without the need for placing a finger glove on one's fin ^¬ gers .

The invention also aims at providing an attractive and long lasting solution.

The invention further aims at providing a nail polish that is not detrimental to one's health, and especially is skin friendly and nail friendly. In this respect, the invention aims at providing a " 3 free", "4 free" or " 5 free" nail polish. Such compositions are free from formaldehyde, dibutylftalate (DBP) and toluene ("3 free"); and also free from formaldehyde resin, TSFR ("4 free"), and free from camphor ("5 free"), respectively.

So as to obtain at least one of the above mentioned aims, ac ^¬ cording to a first embodiment the invention provides a composition comprising the features of claim 1. This composition has the advantage that a user, by applying said composition on her nails, will be able to perfectly operate a touch screen. The composition can preferably be applied to all of the nail's surface. It has shown that the composition has an excellent adherence and con ^¬ sistency after curing same, and as a result will last long on the nail .

The composition according to the present invention is espe cially suitable for formulating a gel nail polish or a shellac nail polish.

The carrier to be used may preferably be a low viscosity carrier, but a somewhat treachy (viscous) carrier may be used as well, as in the case of commonly known gel formulations.

According to a first aspect it is preferred that the composi ^¬ tion comprises at least one electrically conductive polymers. This ensures a homogeneous cured composition that has an excellent conductivity and smooth appearance.

According to a further aspect, as an alternative to or in addition to the first aspect, it is preferred that the composition comprises at least one substance providing an anti-static property or electrical conductivity. These comprise substances that modify the composition such that, especially when the composition has provided a substantially dry, that is to say a cured layer on the nail or artificial nail, an electrical charge is able to move over or through said layer. The connections are preferably positioned (i.e. "oriented") within the formed layer such that the layer ob ^¬ tains an electrically conductive, preferably hydrophilic, surface. Preference is given especially to orienting molecules.

It is preferred for the additive being chosen from at least one of:

[a] a charged polymer, especially a polythiophene based polymer,

[b] a finely dispersable carbon,

[c] a polymer comprising a nitrogen atom in the backbone, and [d] polycarbazole, polyindole, polyazepine, polyacetylene, poly (p-phenylene vinylene) and derivatives hereof;

the concentration of additive in the composition providing an electrical conductivity to the composition. These substances have an especially positive effect on the conductivity of the nail polish.

Preferably, the additive is a polythiophene. More in particu ^¬ lar, preference is given to a charged polymer. A general example of a charged polymer is a cationic polymer. Polythiophene is an example of a cationically charged polymer. It is especially pre- ferred for the polythiophene to comprise an oxygen substituted ring compound.

It is especially preferred for the additive to be poly (3,4- ethylene dioxythiophene ) , also known as poly ( 3 , 4-dioxythiophene ) . This compound has the unique property of providing an excellent conductivity to the formed nail covering. According to a preferred embodiment the invention therefore relates to a composition where ^¬ in said carrier provides an electrical conductivity to the dried or cured composition. Such compound has the additional and unique advantage that it is colorless, which has the consequence that no colour change is obtained. The invention therefor also relates to a composition comprising poly ( 3 , 4-ethylene dioxythiophene ) and a coloring agent.

The compound poly ( 3 , 4-ethylene dioxythiophene) has the ad ^¬ vantage that it is available as a very finely ground and dispersed material, whereas it still yields a nail polish composition with excellent conductivity. Furthermore, a colorless dispersion is ob- tained when combining same with a nail polish composition.

In case poly ( 3 , -ethylene dioxythiophene) is not completely dissolved in a solvent, a dark colored dispersion is obtained, having a dark blue or dark purple or even black colour. In such case, the composition is suitably applicable as a base coat, or as a base composition for manufacturing dark colored (dark purple, dark blue, black or dark grey) nail coating compositions.

Use of poly ( 3 , 4-ethylene dioxythiophene) is especialy preferred when applying same in a liquid comprising poly(styrene sul- phonic acid) as a counter ion. Such combination is available in the art as PEDOT:PSS and is manufactured by and available from Agfa. This combination is available as dispersion and provides a very good base for a composition according to the present invention. It is especially preferred to use a so-called "Generation 1" PEDOT:PSS for providing a base layer, because of the low costs of tis substance, whereas preference is given to a "Generation 3" or higher PEDOT:PSS for especially the top layer that provides a con ^¬ siderable higher conductivity at lower dosage than Generation 1 and that also yields less coloring of the composition.

In addition, poly ( 3 , 4-ethylene dioxythiophene) has the ad- vantage that it may be solved both in aqueous liquids and in or ganic solvent based systems, among which monomer based and solvent based systems. As a consequence, this substance may be suitably used in water based nail polish which has an environmental advantage. The solvability in organic solvents has the advantage that it ca be processed easily in traditional nail polish and all nail polish that are based on curable, i.e. polymerizable, com ^¬ pounds . According to a first aspect, preference is given to a composition comprising an aqueous dispersion or solution.

According to a second alternative aspect the composition comprises a solution or dispersion in an organic liquid.

The composition may be based on a common nail polish as a carrier, to which the additive according to the invention has been added. Thus, the carrier may be formulated as polymerizable mono ^¬ mers in which the additive is solved, dispersed and/or admixed. The polymerization system for use in the present invention, that is to say the monomers, is preferably chosen from at least one of epoxide and acrylate. The advantage of these systems with respect to carbo-di-imide based systems is a higher polymerization rate. The advantage with respect to isocyanate based systems is the lack of toxicity. The use of carbo-di-imide and isocyanate based sys- terns, however, is also within the scope of protection of the present invention.

Advantageously, the composition may comprise a dispersing agent so as to keep the solids present in the composition in a suspending (suspension) or floating (emulsion) state. Settling of substances is preferably avoided, a dispersing agent may contribute to that.

According to a further aspect the invention relates to a composition in which the additive is formed by means of a polymer comprising a nitrogen atom in the backbone. Preference is espe- cially given to polyanilin and polypyrrole, both substances providing a very good conductivity and excellent processability when added to common nail polish formulations. These substances especially have the advantage that they have a good processability in water based carriers and in organic carriers, for example or- ganic liquids. As a special applicability of these materials ref erence is given to the fact that they have an easy synthetic accessibility and, in the case of polyanilin, they may be added as nanofibers, the mechanical flexibility of the polymer providing a great advantage when using this substance in a composition for coating a nail.

It has surprisingly shown that an excellent conductivity of a dry, that is dried or cured, nail polish is obtained by using at least one of polycarbazole, polyindole, polyazepine, polyacety- lene, poly (p-phenylene vinylene) and derivatives thereof, in the composition. It has also shown that these substances are easily processable in common nail polish formulations.

In addition to the functional additive mentioned above, the composition may comprise a soluble resin; optionally in com.bina- tion with for example at least one of a film former, a plasticiz- er, a pigment and a dye. As soluble resin use may for example be made of formaldehyde, acrylate, nitrocellulose, shellac, polyes- ter, polyether, polycarbonate, alkyd or a combination thereof, said resin being compatible with the carrier. The polymerizable substances that are used as carrier, should be suitable for nail polish. The substances mentioned above are mentioned exemplary, other substances are suitable as well, as long as they are usable as part of the carrier, as known in the art.

Preference is given to a composition the carrier comprising monomers that are polymerizable by means of UV radiation or cross- linkers, such that the composition has an electrical conductivity. This ensures that the conductivity is sufficient for operating a touch screen. Such composition is especially suitable for manufacturing gel nails or shellac nails.

Optionally, the composition may comprise a concentration of metal salt, such that an electrical conductivity is obtained in the cured composition. More in particular, systems that are pol- ymerized by Zn(NH ₃ ) ₄ ²⁺ may be used. The Zn substance forms part of the polymer backbone which yields an excellent conductivity in said polymer, thus being sufficient for operating a touch screen. This provides a certain conductivity that can be obtained easily and at low costs. Similar polymerization systems that are induced by metal ions may be used as well.

The additive in the composition according to the present invention may also comprise an ionic liquid, providing a conductivity to the cured composition. Ionic liquids have connections that are comprised of positively charged molecular chains (commonly known as ions) . In such systems, the respective connections are to be chosen from molecules that retain their ionic properties in the cured state of the composition and that provide a conductivity to the cured layer.

The at least one conductivity providing substance is preferably chosen from at least one of: fatty acids, glycerol esters of fatty acids, glycerol and glycerol based compositions, alkanol am- ides, amine-ethoxylates and amide-ethoxylates . These substances provide an excellent conductivity to the cured layer. Furthermore, these substances are compatible with polymer base compounds of the composition, as mentioned before. More in particular, preference is given to the use of glycerol esters of fatty acids, especially stearic acid, as an additive, because of its high conductivity at low dosage and excellent compatibility with base compounds.

An especialy good result is obtained when using glycerol laurate, providing an excellent conductivity in combination with polythiophene , especially in combination with PEDOT:PSS. Conduc- tivity is about ten times higher when adding glycerol laurate compared with a composition not comprising glycerol laurate.

The use of glycerol esters of fatty acids provides an excellent result, especially in the case of gelnails, to wit excellent conductivity and aplicability for operating a touch screen, be- cause gel nails usually are applied as a thicker layer. As a consequence, the concentration of the substance providing the conduc ^¬ tivity in the composition may be higher than compared to the case of using common nail polish. As a result, an improved result is obtained .

It is especially preferred for the additive to comprise a terminal OH. Such compounds have shown to provide an excellent conductivity, are compatible with the base compounds of the compo ^¬ sition and are available at low cost.

Due to the hgh conductivity of the material, it is preferred that the electrically conductive polymer comprises an aromatic ring compound, for example a polyanilin or polypyrrole, or a polymer comprising an unsaturated bond, for example poly ( acetylene ) .

A material providing electrical conductivity may further be comprised of a conductive carbon in finely dispersed state like graphite. For ease of understanding, the term "carbon" will relate to all conductive states of carbon and the like, such as graphite, nanotubes, buckyballs and graphene . Especially when formulating a black nail polish, carbon is a suitable additive. Carbon may also be incorporated in a base layer and a coloring layer may optionally be applied on top of said base layer. A small amount of conductive material in the coloring layer may provide an excellent con- ductivity to the nail composition, in combination with the conductive carbon containing layer. It has also shown that when using a layer that has a reduced conductivity, on top of a carbon contain ^¬ ing layer, yields an excellent conductivity in the multiple layer coating. Within the present invention, the term "carbon" relates to all conductive kinds of carbon, like graphite, nanotubes, buck- eyballs and graphene.

So as to obtain a long lasting conductivity, it is preferred that the additive provides an electrical conductivity the dried or cured composition for enabling one to operate a touch screen.

The additive may comprise an electrically conductive coloring agent. Then, the total amount of additives in the base composition may be reduced, due to the fact that a single additive may both provide for coloring and electrical conductivity, providing both economical advantage and advantage with respect to formulating the composition.

So as to be able to apply the composition according to the invention as a topcoat, it is preferred that the additive compris ^¬ es a colorless electrically conductive substance. This way, the composition will not influence the look of the previously applied colored nail polish on the nail.

The additive may further comprise at least one of [a] a pre ^¬ cious metal and [b] a non-precious metal and an oxidation inhibi ^¬ tor. This provides a goof conductivity and also provides the op ^¬ portunity to yield a coloring effect in the composition, due to the respective metal. The additive may for example be a nano dispersion of [a] a precious metal and [b] a non-precious m.etal and an oxidation inhibitor. The precious metal may suitably comprise silver, preferably a nano-dispersion of silver.

A very good conductivity in an economical fashion, may be ob- tained when the additive is comprised of glycerol stearate, pref ^¬ erably glycerol monostearate . This is an low cost material provid ^¬ ing a very good conductivity in the cured composition. Especially when combining same with a polymerization system based on epoxide or acrylate yields an excellent conductivity. This nail polish also is skin friendly. When adding glycerol monostearate to the composition, dehydration o the nail is prevented effectively. This synergetic combination of effects is surprising.

It is especially preferred that the additive is present in an amount of maximally 0,05 g/ml, preferably maximally 0,03 g/ml, more preferably maximally 0,015 g/ml based on the composition. This provides an excellent conductivity such that a touch screen van be operated, without deteriorating the properties of the nail polish .

The invention also relates to a method for providing a conductive layer to a nail, comprising the step of applying to a nail the composition according to the invention. This provides the advantages as mentioned above with respect to the composition.

Advantageously, the method according to the invention comprises the step of applying to an artificial nail the composition according to the invention.

It is especially preferred that the method comprises the step of applying the composition according to any of the preceding claims to the artificial nail. As a consequence, an excellent op ^¬ erability of a touch screen is obtained, even when a user operates said touch screen with a nail tip, or the bottom side of the nail tip .

The invention further relates to a combination of compositions for coating a nail at least comprising: - a first composi ^¬ tion according to any of claims 1-19 comprising one or more electrically conductive additives, - a second composition comprising a coloring agent and optionally one or more electrically conductive additives. This provides an adequate formation of a nail coating. The composition to be applied firstly, for obtaining a base coat, preferably provides an excellent conductivity, and the subsequent coating layer may provide a coloring layer, optionally comprising a small amount of a conductive substance for providing an adequate conductivity between the coloring layer and the base coat. This provides an excellent conductivity and operability of a touch screen . Optionally, the combination may also comprise a third composition as a top coat. The top coat may be a common top coat, optionally provided with a small amount of an electrically conductive substance.

The composition may be based upon a common nail polish as carrier, to which an additive according to the present invention has been added. The nail polish may be applied in a single layer or in multiple layers (for example a base coat, a coloring layer and an optional top coat) . The carrier may therefore be formulated as a solvent in which an additive is mixed, together with one or more of a film former, a plasticizer, a pigment and a dye. A sol ^¬ vent may be comprised of an alcohol, acetate or water. A soluble resin may be comprised of a formaldehyde, acrylate, nitrocellu ^¬ lose, shellac or polyester, wherein said resin should be compati- ble with the solvent used. Instead of a resin admixed with a solvent, polymerizable substances may be used, as far as they are compatible with the other substances in the nail polish. The substances mentioned above are mentioned as an example, other substances are suitable as part of the carrier, as is known in the art.

Preference is given to a composition comprising a concentra ^¬ tion of electrically conductive polymer that provides an electri ^¬ cal conductivity to the composition. This ensures a conductivity that is sufficient for operating a touch screen. An electrically conductive polymer furthermore has the advantage that it is com ^¬ patible with the base composition of a nail polish, and as a con ^¬ sequence it can be added easily to an existing base nail polish. For example, a single layer nail polish composition ca be ob ^¬ tained .

The substance mentioned before, polythiophene (such as poly ( 3 , -ethylene dioxythiophene ) ) , polyanilin and polypyrrol may be suitably applied in a base coat composition. Such formulation of a base coat proves to have an excellent conductivity. A coloring layer to be applied over said base coat will preferably con- tain a small amount of a conductive substance, just like the op ^¬ tional top coat.

An electrically conductive substance to be applied in the coloring layer and the optional top coatmay be suitably chosen from at least one of: polythiophene (like poly ( 3 , 4-ethylene dioxy- thiophene)), polyanilin, polypyrrole, fatty acids, glycerol esters of fatty acids, glycerol and glycerol based substances, alkanol amides, amine-ethoxylates and amide-ethoxylates . These substances prove to provide an excellent conductivity. Furthermore, these substances have a good compatibility with base compounds of known coloring compositions, as mentioned before. Especially the use of glycerol esters of fatty acids as additive is preferred, since the excellent compatibility thereof with the base compounds. More in particular, these substances do not negatively influence the strength of cured or dried top coat and coloring layer.

Also, the top coat composition will preferably comprise a certain amount of electrically conductive substance, chosen from the same group of substances.

More in particular, it is preferred that he additive comprises a polymer or compound having a very polar (preferably terminal) group, for example an OH or some other suitable functionality. Such substances seem to provide an excellent conductivity, are compatible with the base compounds and are cheap.

So as to provide a long lasting and at all times sufficient conductivity, it is preferred that the additive provides an elec ^¬ trical conductivity to the dried or cured composition.

To be able to use the composition according to the invention in a top coat composition, it is preferred that the additive com ^¬ prises a colorless electrically conductive substance. Then, the composition will not influence the appearance of a previously ap ^¬ plied colored nail polish on the nail.

The composition according to the invention is preferably ap- plied as a base coat, after which a coloring layer and a top coat are applied. The layers are sequentially applied on a nail.

Finaly, the invention relates to the use of a composition according to the invention, especially of polythiophene, preferably poly ( 3 , 4-ethylene dioxythiophene ) , or preferably at least one of polyanilin and polypyrrole, as electrically conductive substance in a composition or coating a nail. Preferred embodiments of this application or use, are depicted in the several preferred embodi- merits of the composition according to the invention as mentioned above and as mentioned in the claims 1-19.

Example I :

To 50 ml butylacetate, 5 g glycerol-monostearate was added.

While stirring slowlyand heating to 50°C, the glycerol- monostearate was dissolved. Then, 1 ml of the solution obtained was added to 10 ml of a standard available clear nail polish. The mixture obtained was stirred thoroughly until a homogeneous solu- tion was obtained. This solution was applied to a nail in the way prescribed for said standard nail polish and cured.

A cured nail polish was obtained that enables the operation of a touch screen.

The standard nail polish did not enable the operation of a touch screen.

Example II:

Excellent results are obtained with the following

compositions (all parts in volume; PEDOT denotes the composition PEDOT:PSS) .

Compositions according to the invention were formulated in the following ranges:

Based on 1 part of a standard base coat (from Alessandro, "twin coat"), 0.001-0.1 part PEDOT and 0.01-0.1 part glycerol laurate was added, yielding a suitably conducting base coat;

Furthermore, based on 1 part of a standard colour layer (Alessandro, "colour coat"), 0.0001-0.1 part PEDOT and 0.001-0.1 part glycerol laurate was added, yielding a suitably conducting colour layer; and

Furthermore, based on 1 part of a standard top layer

(Alessandro, "twin coat"), 0.0001-0.1 part PEDOT and 0.001-0.1 part glycerol laurate was added yielding a suitably conducting top layer . More in particular, the following composition was formulated:

Base layer: 0.01 part PEDOT ("Generation 1") + 0.05 part

glycerol laurate + 1 part standard base layer. Colour layer: 0.00125 part PEDOT ("Generation 1") + 0.0125 part glycerol laurate + 1 part standard colour layer. Top layer: 0.00125 part PEDOT ("Generation 3") + 0.0125 part glycerol laurate + 1 part standard top layer.

In this formulation, the standard base layer, standard colour layer and standard top layer are freely available nail polish for ^¬ mulations that each are suitable for dispersing PEDOT:PSS and glycerol laurate. While continuously cooling of a HEMA or HPMA monomer, so as to prevent premature polymerisation of the rr.ono- mers, the PEDOT :PSS composition was added to the monomers.

The following composition also provides, when coating a natural nail or an artificial nail, after curing a very good operatability of a touch screen, even with less than the following ratios and lower concentrations of PEDOT :PSS and glycerol laurate:

Colour layer: 0.0025 part PEDOT + 0.025 part Glycerol laurate + 1 part standard colour layer.

Wherever in the present specification there is mention of "conducting", "conductivity", "conductive layer" and the like, electrically conducting, electrical conductivity and an electri ^¬ cally conductive layer is meant, such that the operation of a touch screen is possible.

The invention is not limited to the embodiments mentioned be- fore. The invention is only limited by the appending claims.

The invention is also directed to all and every combination of features that have been described independently of each other.