GB2452566A

GB2452566A - A radiation curable, nail coating composition

Info

Publication number: GB2452566A
Application number: GB0717563A
Authority: GB
Inventors: John Robert Wade; Maria Dincheva; Robert Blakie Craik
Original assignee: Chemence Ltd
Current assignee: Chemence Ltd
Priority date: 2007-09-08
Filing date: 2007-09-08
Publication date: 2009-03-11
Also published as: GB0717563D0

Abstract

A radiation curable, nail coating composition comprising a radiation curable substance, at least one dye and/or pigment dissolved and/or dispersed in the composition to impart a colour and a means for causing the dye and/or pigment to remain homogeneously distributed throughout the composition during storage, application and curing of the coating. Said means for causing dye/pigment homogeneity may be an oil or derivatised oil, including castor, cotton, fish, linseed, menhaden, oiticaca, palm kernel, perilla, safflower, sardine, soybean or tung oils. The radiation curable substance may comprise at least one thiol group.

Description

Title: Nail Coatings The present invention relates to nail coatings and particularly to coloured radiation curable nail coatings. By the term "nail" we also include extensions to nails as well as artificial and false nails.

The decoration and colouration of fingernails, toenails and artificial nail extensions rely, almost exclusively, on a number of well established techniques: (1) applying polymer based, pigmented nail lacquers in a solvent or solvents by a coating process and then subsequently evaporating the solvent or solvents (2) mixing, applying and thermally curing two part (liquid and powder) acrylic components and (3) applying by a coating process ethylenically unsaturated, radiation (ultraviolet) curable gels or topcoats and subsequently curing the coating under a low intensity ultraviolet light source for 2 -5 minutes. S...

To achieve the desired combination of high covering power ie high *::::* pigmentation or colouration, strong durability and high gloss finish, the : application of conventional nail lacquers as in (1) above is often followed by the application and curing of a non pigmented, transparent clear or lightly : coloured ultraviolet curable top coat as in (3) above. Alternatively, to * achieve merely a transparent lightly coloured or glitter coating effect, ultraviolet curable coatings are often applied alone and then cured as in (3) above.

In the cases mentioned, because the ultraviolet curable compositions are inhibited from curing by air at the top surface of the coating, the final, desired very high gloss surface finish is achieved in an additional subsequent process by wiping away traces of incompletely cured material with a solvent soaked cloth or pad. The light colouration of the ultraviolet curable topcoats and gels is usually achieved by the dissolution of dyes at parts per million in the formulations. Higher levels of dyes or pigments reduce the transmission of radiation into the coating during curing and lead to slower or incomplete cure and a layer of un-reacted material at the coating surface. These effects are detrimental to the appearance and durability of the coated nail finish especially after the subsequent solvent wiping treatment.

It is an object of the present invention to provide coloured, radiation curable compositions which may be applied to natural or artificial nails and cured by exposure to low intensity ultraviolet light for of the order of 2-5 minutes to provide dry to touch, immediately glossy, durable decorative coatings of high covering power and over fully comparable ranges of colours and shades and effects to those currently provided by conventional polymer based, solvent drying nail lacquers. In decorative nail coatings such colours, shades and effects are generally achieved through pigmentation and/or the addition of other heterogeneous components such as reflective, refractive, pearlescent, metallic, holographic and/or nano particulates. Hereinafter such additional heterogeneous components are referenced by and are included in the terms "pigment", "pigmented", "pigmentation" etc. ***S * * S...

: It is a fundamental requirement of the commercial manufacturing process : * and for the customer-supplied cosmetic end product that the ultraviolet * : curable coating composition be adequately stable in all respects so that the * product is commercially viable and the product retains its specified characteristics and application properties for a defined and acceptable shelf-life.

In respect to pigmented coatings it is essential that the dispersed pigment particles do not settle, agglomerate or aggregate, ie that adequate pigment a dispersion is maintained. If this is not the case, the coating would become non-homogeneous and the colouring and covering power of the composition would be significantly reduced, rendering the product unusable. It is well known in the art that the addition of surface active and/or dispersing agents and polymers helps to maintain adequate pigment dispersion stability in various media (eg. aqueous, solvent, polymer solution and radiation curable compositions etc.).The effectiveness and compatibility of such pigment dispersion stabilisation agents is greatly influenced by the specific composition of the media to be pigmented. In addition, in cosmetic applications, all compositions must comply with worldwide cosmetic regulatory requirements and hence the range of suitable components and agents is significantly reduced compared to products for industrial use.

It is a further object of the present invention to provide coloured, radiation curable cosmetic compositions for natural or artificial nails, compliant with cosmetic regulatory requirements, which exhibit outstanding pigment dispersion properties and dispersion storage stability to provide fully comparable ranges of colours and shades and effects to those currently provided by conventional polymer based, solvent drying nail lacquers and excellent shelf life characteristics. *...

In respect of radiation curable coatings, which cross link and or polymerise * by free radical and/or anionic initiation and propagation of ethylenically 1:h unsaturated components (so called "monomers", "oligomers", "unsaturated polymers" etc.), it is essential that cross linking and/or polymerisation does : . not occur in stored coatings via radiation induced or thermal induced * generation of initiating species. In the case of the former possibility, ultraviolet or visible light curable coatings must be stored in containers which do not transmit the relevant activating wavelengths of light and the product must be applied under lighting similarly free from relevant activating wavelengths.

In the case of thermal stability, a wide range of free radical stabilizers are available such as sterically hindered phenolic compounds for instance 2,6-di-t-butyl-p-cresol. Acidic type thermal stabilisers are also available for instance aliphatic/aromatic sulphonic acids and these stabilise anionic initiated components such as cyanoacrylates. All these stabilisers may be added to the compositions. However, as indicated previously, the range of such additives available for use in cosmetic compositions is restricted by cosmetic regulations. Furthermore, in the case of free radically cured compositions, whilst providing improved thermal stability, the presence of free radical stabilizers reduces the rate of curing, which, coupled with the inhibiting effects of oxygen, increases the proportion of unreacted material at the surface of the coating after curing, which in turn results in a tacky, low gloss surface finish. This can be overcome to some extent by increasing the exposure intensity of the light source and/or extending the duration of exposure but neither of these is desirable or practical for providing an acceptable commercial cosmetic process. The effects of oxygen inhibition in ethylenically unsaturated, radiation curable compositions can be ameliorated by the addition of thiol compounds but these in turn reduce thermal stability and shelf-life and require additional chemical stabilization. S.

: It is a further object of the present invention to provide coloured, radiation curable, cosmetic compositions for application to natural or artificial nails, *::::* compliant with cosmetic regulatory requirements, which exhibit a : combination of excellent thermal stability, resistance to premature cross :. linking and polymerisation and excellent shelf life properties and directly * provide dry to touch, immediately glossy cured films after coating and **SI..

* exposure to low intensity ultraviolet light for of the order of 2-5 minutes.

According therefore to the present invention, we provide a radiation curable, nail coating composition comprising a radiation curable substance, at least one dye and/or pigment dissolved and/or dispersed in the composition to impart a colour and means for causing the dye and/or pigment to remain homogeneously distributed throughout the composition during storage, application and curing of the substance.

Preferably the means for causing the dye and/or pigment to remain homogeneously distributed throughout the substance is an oil or derivatised oil.

Suitably the oil is a drying and/or semi drying oil.

Conveniently the oil is selected from one or more of the following: castor oil, dehydrated castor oil, cotton seed oil, fish oil, linseed oil, menhaden oil, oiticaca oil, palm kernel oil, perilla oil, safflower oil, sardine oil, soybean oil and tung oil.

In one embodiment of the invention the radiation curable substance comprises at least one thiol compound of formula X-(SH)n where X represents an organic moiety and n is an integer from 1 to 10.

The invention is based on the fact that it has been unexpectedly found that the use of drying oil and/or semi-drying oil based dye and/or pigment :: dispersions in combination with radiation curable substances and particularly thiol (possibly poly thiol) compounds in ethylenically unsaturated radiation *,,*. sensitive compositions provide stable, highly pigmented, fast curing coatings : with outstanding surface cure characteristics ie dry to touch, immediately glossy, and durable.

* It is believed that the unsaturated fatty acid moiety of the drying or semi-drying oil, which is capable of free radical and oxidative cure, that is, cure at ambient temperature upon exposure to air, reacts during the exposure of the radiation sensitive composition to provide the unexpected and advantageous properties observed.

The compositions may also include additional components known to those skilled in the art of radiation sensitive compositions to confer specific desired properties for particular applications. This includes surface active materials to modify the rheological, and pigment dispersing properties of the coatings which can similarly and advantageously be drying oil/semi drying oil based agents.

A specific but in no way limiting example of the invention will now be given

Example

A nail coating composition was prepared as described below.

Solution A The following were blended together to form a clear, viscous solution:-Ebecryl 263 Aliphatic urethane acrylate resin 500g Trimethylolpropane trimethacrylate 500g :. Pentaerythritol mercaptopropionate 25g Hydroxycyclohexyl ketone 25g 2-Hydroxypropyl methacrylate log * * *** Solution B ** : **: A castor oil dispersion of 40% Red 6 (CI 15850) (20g) and rheological S.....

* additive Thixatrol ST (an organic derivative of castor oil) (2g) were added to trimethylolpropanetriacrylate (200g) and the mixture was stirred at 1000rpm for 120 minutes Solution B was added to Solution A and the mixture was stirred for 1 hour.

The resultant viscous red coating was applied to artificial nail tips in a thin layer and the tips were immediately exposed to light from a UV Exposure Unit for 120 secs. The result was a dry, non-tacky, tough, red coating of high gloss and indistinguishable in appearance from that of a tip coated with conventional solvent based nail lacquer and dried for 10 minutes. Se * * *** * S IS'S 555S * I S...

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Claims

Claims 1. A radiation curableq nail coating composition comprising a radiation curable substance, at least one dye and/or pigment dissolved and/or dispersed in the composition to impart a colour and a means for causing the dye and/or pigment to remain homogeneously distributed throughout the composition during storage, application and curing of the coating.
2. A coating composition as claimed in claim 1 in which the means for causing the dye and/or pigment to remain homogeneously distributed throughout the composition is an oil or derivatised oil.
3. A coating composition as claimed in claim 1 or claim 2 in which the oil is a drying and/or semi drying oil.
4. A coating composition as claimed in claim 3 in which the oil is selected from one or more of the following: castor oil, dehydrated castor oil, cotton seed oil, fish oil, linseed oil, menhaden oil, oiticaca oil, palm kernel oil, perilla oil, safflower oil, sardine oil, soybean oil and tung oil. j
5. A coating composition as claimed in any of the preceding claims in which the radiation curable substance comprises at least one thiol compound of * formula X-(SH)n where X represents an organic moiety, and n is an integer : from 1 to 10.
6. A coating composition substantially as hereinbefore described with ***S.S * reference to the example.

Abstract A radiation curable, nail coating composition comprising a radiation curable substance, at least one dye and/or pigment dissolved and/or dispersed in the composition to impart a colour and a means for causing the dye and/or pigment to remain homogeneously distributed throughout the composition during storage, application and curing of the coating. I. b

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