WO2007137936A1

WO2007137936A1 - Product for demonstrating efficacy of sun-protection material

Info

Publication number: WO2007137936A1
Application number: PCT/EP2007/054541
Authority: WO
Inventors: Babu Cherian; Ravi Krishnan; Vinod Kumar
Original assignee: Unilever Plc; Unilever N.V.; Hindustan Unilever Limited
Priority date: 2006-05-29
Filing date: 2007-05-10
Publication date: 2007-12-06

Abstract

The invention provides for a product that can be used to demonstrate the efficacy of cosmetics against UV radiation, in a quick and simple manner, which would be of immense value to the consumers at the point of sale such as in shops and supermarkets and on the streets and educational institutions, to name a few. Another object of this invention is to provide a convenient product for the consumer to visualize the benefits of cosmetic material against UV radiation.

Description

PRODUCT FOR DEMONSTRATING EFFICACY OF SUN-PROTECTION MATERIAL

Technical field

The present invention relates to a product for demonstrating efficacy of a cosmetic material against UV radiation.

Background and prior art

UV radiation constitutes a part of the spectrum of light emitted by the sun and has wavelength less than 400 nanometers. This radiation is of three types, UVA radiation having wavelengths in the range of 320 to 400 nanometers, UVB radiation having wavelengths in the range of 280 to 320 nanometers and UVC covering the wavelength range less than 280 nm.

UVA and UVB radiations are collectively suspected to cause photoaging of skin, dryness, deep wrinkle formation, mottled pigmentation and the breakdown of elastic tissues and collagen and in extreme cases, skin cancer.

While, medical treatment is required to cure extreme cases, cosmetic preparations in the form of lotions, creams, gels, powders etc, are used by people as a first line of defense against UV radiation, in many parts of the world.

Cosmetic preparations affording protection against UV radiations are rated according to their sun protection factor, SPF. This is the ratio of the minimal erythemal dose (i. e., the UV dose required to cause minimal erythema) in protected skin as compared to the same dose in unprotected skin. It therefore describes the efficiency of a sunscreen against sunburn. Sun protection products that have SPF > 15 are generally considered "sunblocks", while those having SPF of 15 or less are either "sunscreen "or" suntanning" products. Many organic sunscreen and sunblock products protect the skin from UVB and UVA radiation.

While several cosmetic products are available, which provide protection against UV radiation, one has to wait to visualize their benefits over a period of continued usage. There is no user friendly method of visualizing their actual benefits while the sunscreen is in action. Furthermore, it has also been observed that consumers often apply a sub-optimal amount of sunscreen to their skin. Commercial sunscreens typically must be applied in an amount of 2 milligrams per square centimeter to the entire region of the body that is exposed to the sun. It is found that consumers actually apply about 0.5mg/cm2. If a lesser amount of sunscreen is applied, then the claimed SPF value for the sunscreen is not reached and maintained. Therefore, the amount of protection that the consumer receives is related to the amount of sunscreen applied in addition to the SPF value on the bottle. Insufficient application of sunscreen will lead to lower protection.

In addition, a common misconception prevalent amongst people is that sunrays do not cause much harm in winter, monsoons and when the climate is generally cloudy. This therefore, leads to the belief that sunscreens are not essential during the above periods. Sunrays emit UV radiation round the year and all around the globe, with variations in the intensity. It has been proven that whatever be the duration of exposure to sunlight and whatever be the intensity thereof, sunburns and other undesirable effects do happen, without the knowledge of the people. On continued and/or prolonged exposure to sunlight, this degree of sunburn increases, leading to further problems.

There have been some attempts in the past to provide indications of the harmful effects of UV radiations by way of devices such as plastic gauges or monitors that can be applied to clothes or attached to skin. These devices have an indicator that alerts the user when UV radiation is reaching the device. Gauges and devices known in the art suffer from the primary drawback that they are not essentially UV transparent. Furthermore, gauges and devices are attached to the skin or clothing using a separate adhesive layer. However, adhesive layers suffer from the drawback that they can fail causing the gauge or device to fall off and become useless.

Another method is to put a temporary visual indicator in the sunscreen composition itself. The indicator renders the sunscreen colored when it is applied, but it becomes invisible shortly after application. The indicator can be reactivated temporarily to the visible form so that the user can verify the presence of the sunscreen. However, this method is inconvenient because the user must periodically reactivate the indicator by applying a disclosing solution, such as a spray to modify pH, to determine whether the sunscreen is still present. In addition, such methods rely on the consumer remembering to use the reactivation device. A method described in WO 02 03949 (The Procter & Gamble Company) pertains to a sun-protection kit comprising a sunscreen and an indicator. The indicator includes a photochromic molecule and a carrier, which is applied directly to the skin. While this method does not require a separate adhesive layer, it is however not completely suited for demonstration purpose as the product needs to be applied directly on the skin, which many people would not be comfortable with. Many sunscreen actives are known to penetrate the skin; thereby leading to allergic reactions. Therefore, this method is not suited for such sunscreen actives. On the other hand, the user needs to expose himself to sunlight or UV light to visualize the benefits.

Therefore, there exists an unmet need for a product that is capable of demonstrating the efficacy of cosmetic materials against UV radiation, which is devoid of the disadvantages, limitations and drawbacks of the prior art. The present inventors have offered a solution to this problem of prior art by way of the invention. The invention provides for a product that can be used to demonstrate the efficacy of cosmetics against UV radiation, in a quick and simple manner, which would be of immense value to the consumers at the point of sale such as in shops and supermarkets and on the streets and educational institutions, to name a few.

It is therefore an object of the invention to overcome at least some of the cited drawbacks, disadvantages and limitations of the prior art.

Another object of this invention is to provide a convenient product for the consumer to visualize the benefits of cosmetic material against UV radiation.

Summary of the invention

According to an aspect, the present invention relates to a product for demonstrating efficacy of a cosmetic material against UV radiation, wherein the product comprises a panel, which includes a depiction and a coating comprising a photochromic substance, said coating capable of producing a visually perceptible change when exposed to a source of UV radiation, said change is prevented on application of said cosmetic material to at least a part of said coating.

In a preferred aspect, the depiction is coated with the photochromic substance on at least a part thereof. In a further preferred aspect, the coating of the photochromic substance is transparent. - A -

In a still further preferred aspect, the panel is made of paper.

The present invention offers significant technical advancement over devices, gauges and other accessories described in prior art, as well as over methods that essentially involve human beings or other animals as a subject. This product can be used to demonstrate the efficacy of cosmetic material against UV radiation, thereby helping the people in general to appreciate the ill-effects of UV radiation and the positive benefits of cosmetics.

This product can therefore serve as an effective instrument in promoting the sales of cosmetics.

The invention will now be described in greater details in the detailed description that follows.

Detailed description

The present invention relates to a product for demonstrating efficacy of a cosmetic material against UV radiation, wherein the product comprises a panel, which includes a depiction and a coating comprising a photochromic substance, said coating capable of producing a visually perceptible change when exposed to a source of UV radiation, said change is prevented on application of said cosmetic material to at least a part of said coating. The term "panel" for the purpose of this invention means a flat thin piece of material.

The term "depiction" for the purpose of this invention includes a textual representation or an image.

Preferably, the panel is made of paper, paper board, plastic, glass, polymer or a combination thereof, more preferably the panel is made of paper. The panel is preferably square or rectangular in shape, but it would be apparent to the reader that the panel can be made in any other shape and all such variations in shape are within the scope of the present invention. Preferred dimensions of the panel, when it is square, range from 10 cm X 10 cm to 3 cm X 3 cm, more preferably 5 cm X 5 cm. It is to be understood that the preferred dimensions indicated herein do not restrict the scope of the invention, as the panel could be made in any required dimensions. Preferred overall thickness of the panel ranges from 1 mm to 20 mm, more preferably from 2 mm to 15mm and most preferably from 2 mm to 10 mm. The panel is preferably two dimensional although the overall product can assume a three dimensional configuration. In an embodiment, the panel can be stuck or attached to e.g. a tile thus making it a three dimensional product.

The panel includes a depiction which is preferably selected from a sign, symbol, graphical representation, an image, 2 or 3 dimensional picture, an embossed image or a holographic image or a combination of the above. More preferably, the depiction is of an external part of the human body and most preferably it is a face of a human being. Preferred method of including such depictions on the panel is offset printing, although any suitable method can be employed. General processes for such printing are known to the person in the art.

The panel also includes a coating comprising a photochromic substance. These are substances that change color reversibly when exposed to UV radiation. Photochromic means that the substance changes color in the presence of radiation due to a conformational change of the molecule that is induced by radiation. This conformational change is a reversible structural change governed by mechanisms such as ring opening or closing reactions, electron transfer reactions, or radical dissociation reactions.

For a molecule to be photochromic, it must be capable of reverting back to its original structure when exposure to the exciting radiation ceases. Furthermore, to be photochromic, the molecule must be capable of changing and reverting back to its original color, or nearly its original color, multiple times upon repeated exposures to radiation.

Photochromic substances

Various classes of photochromic molecules are suitable for use in this invention. Preferred classes include spirooxazines, spiropyrans, fulgides, fulgimides, bisimidazoles, and viologen derivatives, and combinations thereof. Spirooxazines, spiropyrans, and fulgides are known in the art and the methods for their preparation are disclosed in literature.

"Spirooxazines" are molecules having a 3H oxazine ring in which the number 3 carbon atom of the ring is involved in a spiro linkage. The molecule contains condensed ring structural features such that the heterolytic cleavage of the carbon-oxygen bond results in a change of valence-bond structure and conformation of the molecule, as exemplified below.

Ultra- Violet

Radiation

Colorless Colored

Generalized Photochromic Reaction of Spirooxazines

Suitable spirooxazines for use in this invention have the general formula:

Group 'a' is a spiro-linked group bonded to the carbon at the 3 position in the oxazine ring. Group 'a' can be monocyclic or polycyclic. Group 'a' is preferably bicyclic.

Group 'a' can be unsubstituted (i.e. when each R2 is a hydrogen atom) or substituted (i.e. when at least one R2 is not a hydrogen atom). Group 'a' is preferably selected from the group consisting of aromatic groups, substituted aromatic groups, heteroaromatic groups, and substituted aromatic groups. In a preferred embodiment of the invention, group 'a' is selected from the group consisting of heteroaromatic groups (e.g. indolyl, benzoxazolyl and benzothiazolyl) and heterocyclic groups (e.g. piperidinyl groups).

Group 'b' is a fused group bonded to the carbon atoms at the 5,6 position in the oxazine ring. Group 'b' can be monocyclic or polycyclic. Group b is preferably bicyclic or tricyclic. Group 'b' can be unsubstituted (i.e. when each R3 is a hydrogen atom) or substituted (i.e. when at least one R3 is not a hydrogen atom). In a preferred embodiment of this invention, group 'b' is selected from the group consisting of naphthyl, anthryl and phenanthryl.

R1 is a hydrogen atom or a lower monovalent hydrocarbon group. R1 is preferably a hydrogen atom.

Each R2 is independently a hydrogen atom, or a substituent group bonded to a carbon atom in the ring of group a. Substituent groups for R2 are exemplified by monovalent hydrocarbon groups, substituted monovalent hydrocarbon groups, carbocyclic groups, substituted carbocyclic groups, heteroaromatic groups, substituted heteroaromatic groups, heterogeneous groups, substituted heterogeneous groups, a hydroxyl group and an amino group. Preferred heterogeneous groups include alkoxy groups, such as methoxy and ethoxy groups and cyano groups.

Each R3 is independently a hydrogen atom, a monovalent hydrocarbon group, an amino group, a substituted monovalent hydrocarbon group (e.g. alkoxy groups, such as methoxy, ethoxy and cyano groups), a heterogeneous group or a substituted heterogeneous group.

The subscript x represents the total number of hydrogen atoms and substituent groups bonded to carbon atoms in the ring of group 'a'.

The subscript y represents the total number of hydrogen atoms and substituent groups bonded to carbon atoms in the ring of group 'b'.

Suitable spirooxazines for use in this invention are typically selected from the group consisting of:

R1 , R2, and R3 are as described above.

Spiro (indoline-2, 3'- (3H) naphth (2, 1-b)(1 , 4) oxazine) have the formula:

wherein R1 , R2, and R3 are as described above. Examples of spiro(indoline-2,3'-(3H)- naphth (2,1-b)(1 ,4)-oxazines) include 1 ,3,3-trimethylspiro(indoline-2,3'-(3H)-naphtha-(2,1- b)(1 ,4) oxazine), and 3-ethyl-9'-methoxy-1 ,3-dimethylspiro(indoline-2,3(3H)-naphth-(2,1- b)(1 ,4) oxazine). Spiro(indoline-2,3'-(3H)-pyrido-(3,2-f)(1 ,4)-benzoxazines) have the formula

wherein R1 , R2, and R3 are as described above. Suitable spiro(indoline-2,3'-(3H)-pyrido- (3,2-f)(1 ,4)-benzoxazines) include 1 ,3,3-trimethylspiro(indoline-2,3'-(3H)-pyrido-(3,2-f)- (1 ,4) benzoxazine) and 1 ,3-dihydrospiro(indoline-2,3'-(3H)-pyrido-(3,f)-(l,4)-benzoxazine).

Spiropyrans "Spiropyrans" are molecules having two heterocyclic parts linked together by a common tetrahedral sp3 carbon atom. The two heterocyclic parts are in different orthogonal planes. A benzopyran structure in at least one heterocyclic part is common to all spiropyrans. Spiropyrans undergo a heterolytic cleavage of the carbon oxygen bond similar to that of spirooxazines. Photochromic interconversion of a spiropyran is exemplified below.

Spiropyrans suitable for use in this invention have the following general formula.

Group 'c' is a spiro-linked group selected from the group consisting of heterocyclic, substituted heterocyclic groups, heteroaromatic groups and substituted heteroaromatic groups. Group 'c' is preferably selected from the group consisting of azaheterocyclic groups and non-azaheterocyclic groups. Azaheterocyclic groups include indoline; benzothiazoline; benzoxazoline; benzoselenazoline; 1 ,3-thiazolidine; 1 ,3-oxazolidine; pyrrolidine; 1 ,3-thiazine; 1 ,4-thiazine; 1 ,3-oxazine; piperidine; phenanthridine; acridine; and quinoline. Non-azaheterocyclic groups include benzodithiole; benzoxathiole; benzopyran; naphthopyran, xanthene; and dithiole.

Each R4 is independently selected from the group consisting of a hydrogen atom, monovalent hydrocarbon groups (e.g. alkyl groups), substituted monovalent hydrocarbon groups, heterogeneous groups (e.g. alkoxy, alkoyl, halogenated hydrocarbon groups, and carboxy groups), substituted heterogeneous groups, aromatic groups (e.g. phenyl and naphthyl), substituted aromatic groups, heteroaromatic groups, substituted heteroaromatic groups, cyclic groups, substituted cyclic groups (e.g. cycloalkyl groups), heterocyclic groups, substituted heterocyclic groups, nitro groups, hydroxy groups and amino groups.

Each R5 is independently selected from the group consisting of R4 and with the proviso that two instances of R5 may be bonded together to form a fused group selected from the group consisting of aromatic groups (e.g. phenyl and naphthyl), substituted aromatic groups, heteroaromatic groups, substituted heteroaromatic groups, cyclic groups, substituted cyclic groups (e.g. cycloalkyl groups), heterocyclic groups, substituted heterocyclic groups, nitro groups, hydroxy groups and amino groups.

In a preferred embodiment of the invention, the spiropyrans are naphthopyrans. Naphthopyrans have the following formula:

wherein group 'c', R4, and R5 are as described above.

Examples of suitable spiropyrans to use in this invention include 1',3',3-trimethylspiro(2H- 1 )- benzopyran-2,2'-indoline-6-nitro-1 ',3',3'-trimethylbenzoindolinospiropyran, 3-ethyl-8- methoxy-6-nitro(2H-l)-benzopyran-2-spir-2'-(3'-methylthiazolidine), 8-bromo-6-nitro- ndolinospirobenzopyran, and 8-nitrindolinospirobenzopyran. Fulgides

"Fulgides" are dimethylene succinic anhydride derivatives. Fulgides convert from a colorless to a colored form upon exposure to UV radiation. Unlike the spirooxazines and spiropyrans, the colored form is a closed ring system, and the colorless form results from a ring opening reaction.

Colorless Colored

Generalized photochromic reaction of mono-aryl fulgides

Fulgides suitable for use in this invention include those having the general formula:

wherein R6, R8 and R9 are each independently selected from the group consisting of a hydrogen atom, a monovalent hydrocarbon group (e.g. an alkyl group such as methyl or ethyl), a substituted monovalent hydrocarbon group, a heterogeneous group (e.g. a halogenated hydrocarbon group or alkoxy groups) and a substituted heterogeneous group.

R7 is selected from the group consisting of an aromatic group, a substituted aromatic group (e.g. phenyl, phenoxy or alkoxyaryl), a heteroaromatic group, a substituted heteroaromatic group, a carbocyclic group, a substituted carbocyclic group, a heterocyclic group (e.g. thienyl and furanyl) and a substituted heterocyclic group (methylthienyl and methylfuranyl).

Examples of suitable fulgides for use in this invention include alkoxyaryl fulgides such as methoxyaryl fulgides and heterocyclic fulgides such as furyl fulgides and adamantylidene fulgides.

Suitable alkoxyaryl fulgides are exemplified by the following:

Suitable heterocyclic fulgides include those selected from the group consisting of:

wherein R^6' is an alkyl group such as methyl, ethyl, «-propyl, or isopropyl. Fulgimides

Fulgimides

Fulgimides are similar to the fulgides described above. Fulgimides have the general formula:

wherein R6, R7, R8 and R9 are as described above. Fulgimides are exemplified by:

wherein R6 is as described above and each R11 is independently selected from the group consisting of a hydrogen atom, a monovalent hydrocarbon group (e.g. an alkyl group such as methyl or ethyl), a substituted monovalent hydrocarbon group, a heterogeneous group (e.g. a halogenated hydrocarbon group, alkoxy groups) and a substituted heterogeneous group.

Bisimidazoles

The UV-induced photochromic mechanism of bisimidazoles is a radical dissociation.

Suitable bisimidazoles have the following general formula:

wherein each R12 is independently selected from the group consisting of an aromatic group, a substituted aromatic group (e. g., phenyl, phenoxy or alkoxyaryl), a heteroaromatic group and a substituted heteroaromatic group. Preferably R12 is selected from the group consisting of a phenyl group, a methylphenyl group, a methoxyphenyl group and a halogenated phenyl group.

Viologen Derivatives

Viologen derivatives are also suitable to use as the photochromic molecule of this invention. The photochromic mechanism of viologen takes place via an electron transfer reaction between the halogen and the nitrogen atoms. Viologen derivatives have the general formula:

wherein each R13 is independently selected from the group consisting of a monovalent hydrocarbon group (e.g. an alkyl group such as methyl or ethyl), a substituted monovalent hydrocarbon group, a heterogeneous group (e.g. a halogenated hydrocarbon group or alkoxy groups), a substituted heterogeneous group, an aromatic group, a substituted aromatic group (e.g. phenyl, phenoxy or alkoxyaryl), a heteroaromatic group, a substituted heteroaromatic group, a carbocyclic group, a substituted carbocyclic group, a heterocyclic group (e.g. thienyl and furanyl) and a substituted heterocyclic group (methylthienyl and methylfuranyl); and each A represents a halogen atom.

Suitable photochromic molecules are known in the art and are commercially available. For example, PPG Industries Inc. of Monroeville, Pennsylvania sells a line of photochromic dyes that can be activated (i.e. change color) by exposure to ultraviolet radiation having a wavelength of 340 to 360 nanometers. These photochromic dyes include Photosol 0265, 33672,5-3 (a spirooxazine), 5-83,7-106, and 7-49. Photochromic molecules in a variety of colors are suitable for this invention.

However, of the Photosols, preferred photochromic molecules are blue or purple when exposed to UV radiation and colorless when not exposed. Generally, the blue and purple Photosols revert back to their colorless form more quickly than red and pink.

Furthermore Photosols that turn pink and red when exposed to UV radiation absorb some UV radiation having wavelengths of 360 to 420 nanometers. Many sunscreens do not block UV radiation having wavelengths greater than 365 nanometers.

Therefore, photochromic molecules exhibiting a color change when exposed to UV radiation having wavelengths of 365 nanometers or less are preferred.

In a preferred embodiment, the depiction is coated with the photochromic substance on at least a part thereof. In a more preferred embodiment, the entire depiction is coated with the photochromic substance and in a highly preferred embodiment, the coating is transparent. By "transparent" is meant that at least 90% of the incident light is able to pass through the coating. Preferred methods of coating the photochromic substance include offset printing, screen printing, gravure printing or flexography printing, more preferably screen printing. Such methods are known to a person in the art. Preferred thickness of this coating is from 3 microns to 400 microns, more preferably from 5 to 300 microns. The coating preferably has from 0.005 to 20 % w/w, more preferably 0.01 to 10% w/w of photochromic substance.

The coating is capable of producing a visually perceptible change when exposed to a source of UV radiation. This source includes natural sources i.e. sunlight and artificial sources such as UV lamps. By visually perceptible change is meant that the coating changes from one state to another, which can be readily perceived by people through sight. In a preferred embodiment of the invention, the coating is colorless in the absence of UV radiation and becomes colored when exposed to UV radiation. Alternatively, the coating is partially colored in the absence of UV radiation, and changes (e. g., augmented or varied) on exposure to UV radiation. In an alternative embodiment of the invention, the coating is colored when not exposed to UV radiation, and becomes a different color when exposed to UV radiation. In another alternative embodiment of the invention, the coating is colored in the absence of UV radiation and colorless when exposed to UV radiation. The color (or lack thereof) upon exposure to UV radiation is determined by the selection of the photochromic molecule or molecules and appropriate selections can be made depending on the requirement.

To prevent the coating and product from getting damaged upon usage and to make it reusable, the panel is preferably laminated, after coating the photochromic substance. Preferred material for lamination is PET (polyethyleneterepthalate) having thickness from 5 microns to 100 microns, preferably from 10 microns to 50 microns and more preferably from 10 microns to 30 microns. Various other materials or films for lamination can be employed. Methods of lamination are well known to a person skilled in the art.

In a highly preferred embodiment, the product comprising the panel further comprises indicia, pertaining to the cosmetic material. This indicia could be in the form of a mark, sign , symbol, design, image, hologram, 2 or 3 dimensional representation, a trade mark, an advertisement, method of usage of the cosmetic material, information pertaining to the cosmetic material, promotional offers or any combinations thereof. The present product is used to demonstrate efficacy of cosmetic materials against UV radiation. One of the advantages of this invention is that it can be used with sunscreens that are known in the art. Any sunscreen that prevents ultraviolet ("UV") radiation from penetrating deep into the skin, and that does not destroy the efficacy of the coating and or the lamination, is suitable for use in this invention. The term "cosmetic material" used herein includes cosmetic preparations and cosmetically acceptable compounds. Non- limiting examples of cosmetic preparations are creams, gels, combination of cream and gel, lotions, cleansing milk, skin pore cleaning preparations and clear nail paints, which are normally used for direct application to the skin and nails and which themselves are substantially free of inorganic particulate materials that render these preparations opaque.

Cosmetically acceptable compounds include organic sunscreens, and inorganic materials such as transparent titanium dioxide, transparent iron oxide, transparent cerium oxide, transparent zinc oxide or combinations thereof.

The invention and its' method of use will now be described in further details with the help of the following figures, which form non-limiting embodiments of the invention.

Brief Description of the Figures

Figure 1 shows front view of an embodiment of a product according to the invention, with various components therein, prior to exposure to UV light.

Figure 2 shows the front view of the same embodiment after exposure to UV light

Figure 3 shows the front view of the embodiment of figure-1 where the visually perceptible change is prevented on application of a cosmetic material to a part of the coating.

Detailed Description of the Figures

Figure 1 shows front view of an embodiment of a product according to the invention, with various components therein, prior to exposure to UV light. In this figure, the product 1 comprises a panel 2, which is square in shape and having dimensions of 110 mm x 1 10 mm. The panel is made of 270 gsm Cyber XL board (ex -ITC). The panel has a depiction 3 in the form of a human face and indicia 4, which were printed by four-color offset- printing using normal ink. The depiction 3 is coated with a single coat of photochromic substance by screen printing using water-based photochromic ink that changes from colorless to purple color on exposure to UV radiation, leaving a small region uncoated. The depiction has coated region 6 and un-coated region 5. These coated and un-coated regions help the consumer to appreciate the efficacy of the cosmetic material by providing a ready reference area for comparison. The ink was supplied by the company Luminescence, Harlow, Essex, UK. The screen material was polyester with recommended squeeze angle of 50 to 60 degrees. The ink was dried by normal air drying, although Infra-red radiation could also be used for the same purpose. The panel 2 was later laminated with a glossy PET 12 micron film (ex, Garware polyester).

Figure 2 shows the front view of the same embodiment after exposure to UV light for approximately 2-3 seconds. The figure shows that the region 6 has turned dark because of the effect of UV radiation on the coating of the photochromic substance. This shows a visually perceptible change, which is due to the effect of UV radiation.

Figure 3 shows the front view of the embodiment of figure 1 where the visually perceptible change is prevented on application of a cosmetic material to a part of the coating. To a region 7 of the depiction 3 is applied commercially available cosmetic preparation "Fair & Lovely" cream, which contains UV-protecting sunscreens Parsol MCX and Parsol 1789. The cream is not applied to the other half area 6 of the depiction 3. The product 1 is then exposed to UV radiation for 2-3 seconds. The figure then shows that the region 6, where the cream was not applied, immediately turned dark, whereas the region 7 carrying the cream did not turn dark. The color of region 7 matched with that of un-coated region 5, thereby indicating to the consumer that the cream was efficacious. The cream prevented the visually perceptible change from colorless to dark colored one, thereby demonstrating its' efficacy in affording protection against UV radiation. On removing the source of UV- radiation, the product returned to its' original state, described in figure-1. The time taken for the product to revert back typically is a function of several factors such as the concentration of the photochromic substance and the concentration of the cosmetic material, the time of exposure, the inherent nature of the photochromic substance and the cosmetic material and is typically from 10 seconds to 30 seconds. The cream could also be wiped out or washed to make it re-usable, as the panel has a laminate coating.

The present invention hereby provides for a product that can be used to demonstrate the efficacy of cosmetics against UV radiation, in a quick and simple manner, which would be of immense value to the consumers at the point of sale such as in shops and supermarkets and on the streets and educational institutions. It also provides for a convenient product for the consumer to visualize the benefits of cosmetic material against UV radiation.

Claims

1. A product for demonstrating efficacy of a cosmetic material against UV radiation, wherein said product comprises a panel, which includes a depiction and a coating comprising a photochromic substance, said coating capable of producing a visually perceptible change when exposed to a source of UV radiation, said change is prevented on application of said cosmetic material to at least a part of said coating.

2. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in claim 1 , wherein said depiction is coated with said photochromic substance on at least a part thereof.

3. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in any preceding claim, wherein said coating is transparent.

4. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in any preceding claim, wherein said coating changes from colorless to colored state.

5. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in any preceding claim, wherein said coating is done by offset printing, screen printing, gravure printing or flexography printing.

6. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in claim 5, wherein said coating is done by screen printing.

7. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in any preceding claim, wherein said panel is made of paper, paper board, plastic, glass, polymer or a combination thereof.

8. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in claim 7, wherein said panel is made of paper.

9. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in claim 8, wherein said panel is laminated, after coating said photochromic substance.

10. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in any preceding claim, wherein said depiction is of an external part of a human body.

1 1. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in any preceding claim, wherein said panel comprises indicia, pertaining to said cosmetic material.

12. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in any preceding claim, wherein said photochromic substance is selected from the class of spirooxazines, spiropyrans, fulgides, fulgimides, bisimidazoles, or viologen derivatives.

13. A product for demonstrating efficacy of a cosmetic material against UV radiation as claimed in any preceding claim, wherein said cosmetic material includes cosmetic preparations and cosmetically acceptable compounds.