GB2337460A

GB2337460A - Depilatory method using aerosol formulation which stiffens when applied to the skin

Info

Publication number: GB2337460A
Application number: GB9911669A
Authority: GB
Inventors: Susan Ayton; Jonathan Bennett
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-05-20
Filing date: 1999-05-19
Publication date: 1999-11-24
Anticipated expiration: 2019-05-19
Also published as: GB9911669D0; GB2337460B

Abstract

A depilatory composition is dispensed from a pressurised container having release means onto a chosen area of skin and allowed to stiffen and harden for a fixed period of time. This stiffened composition is then removed from the surface of the skin and thereby removes the unwanted hair from that region of skin. The preferred depilatory composition is a commercially available water based contact adhesive AFFIX (Evode Ltd., Stafford, UK) which is applied as a foam and then spread over the desired area of skin using, say, a spatula, to a thickness determined by the properties of the hair to be removed. The film of adhesive stiffens as a volatile component, such as water, evaporates. Other polymer materials may also be used. The stiffened film layer may also be removed by the use of a flexible and/or adhesive strip which is applied to the stiffened film layer and once adhered to same, it is then used to remove said stiffened layer from the skin along with the unwanted hair. The depilatory composition may undergo a distinct change in appearance, e.g. change in colour, as it stiffens. The composition may also contain other components such as perfume, which may improve the appearance and/or condition of the skin. The pressurised container may be an aerosol can.

Description

I- 1 - 2337460 Improvements in or relatincr to depilatorv methods The

present invention relates to a method of removing hair, and to depilatory means.

For aesthetic reasons it is often desired to remove hair from skin. The known methods of achieving this can be broadly categorised into four main types.

The first type of process is shaving, in which the hair is cut off at the level of the skin. This type of process does not remove the root of the hair and so the hair grows back quite quickly so that frequent shaving is necessary.

Furthermore, the hair growth may become stronger and thicker as a result of the shaving.

is The second type of process involves application to the skin of a chemical agent, usually in the form of a liquid or cream but sometimes in the form of an aerosol spray. Such chemical agents are often based on derivatives of thioglycolic acid. Chemical depilatory agents are described in, for example, GB 1381669, GB 1329029, GB 1296356, GB 1264319, GB 1142090, EP 0096521 and EP 0095916. The chemical agent dissolves the hair and is then scraped or washed from the skin. This type of process suffers from the disadvantage that the chemical agents may have an unpleasant smell, as a consequence of which they are generally masked with perfume or 2 packaged in sealed dispensing apparatus as is described in GB 824,429.

The hair dissolving process also takes a long time, for example 20 to 30 minutes, and the chemical agents may irritate the skin or give rise to allergic reactions. Furthermore, once again the hair root is not removed and the hair grows back quite quickly.

The third type of process utilises a hair removing apparatus, which mechanically plucks the hairs from the skin.

This has the advantage that the roots of the hairs are sometimes removed thereby leading to slower re-growth but suffers from the disadvantages that it requires the use of a complex apparatus. It may also be timeconsuming to pass the apparatus over a large area, for example a leg, and as the hairs are plucked throughout that period, the discomfort involved in plucking hairs out by the roots may be of extended duration. In addition, finer hairs are sometimes broken off at skin level or above, leaving the root in place.

The fourth type of process is known as waxing and involves the application of hot or warm wax to the skin and subsequently applying a flexible substrate. When the wax has cooled and stiffened it is removed by means of the flexible substrate from the skin, plucking out hairs with it. The hot or warm wax is normally applied to the skin with a disposable spatula. Waxing is similar to the third type of process in 1 that it relies on mechanical plucking of the hair from the skin and therefore has the advantage that the hair is plucked out along with its root thereby leading to slower re-growth and an improved cosmetic appearance to the skin as compared, for example, to shaving. In fact, as the wax material contacts the hair intimately along its length the hair is bound into the wax leading to efficient removal of all or nearly all of the unwanted hair. The waxing process is also quite fast as the wax stiffens very soon after application and the removal of the wax is accomplished with a simple pull.

Thus, any discomfort is over very quickly. Warm waxing, in which warm (as opposed to hot) wax is used, is commonly used for hair removal and is used both in salons and in the home.

Waxing, however, suffers from several disadvantages.

Firstly, the wax must be heated before use in order to soften it so that it may be applied to the skin. This heating is time-consuming and requires the use of a heating apparatus. Waxing can cause irritation to the skin and it is known that waxing should not be repeated on the same area of skin in the same treatment. Remaining hairs must be removed by another method. Hot wax is more efficient at hair removal than warm wax but suffers from the disadvantage that the temperature of the wax causes sensitisation as it is applied to the skin and can cause vasodilation and redness of the skin. Repeated reheating of wax can impair the performance of the wax and - 4 achieving and maintaining the wax at the correct temperature is not easy especially in home use.

Furthermore, in salons a single pot of wax is commonly used for a number of persons. Wax is transferred from the pot to the skin using a spatula which is then often returned to the pot to pick up more wax. To use a single pot of wax for each person is inconvenient in a salon and the desirable practice of using a new spatula each time wax is transferred from the pot to the skin is often not followed because it is wasteful and impractical. Thus there exists the possibility of transferring disease between those persons via the pot of wax, especially as during the waxing process blood may flow from the skin where hairs have been plucked out.

Waxing is also known to leave a residue on the skin which must be washed off, often with an emollient or solvent, before, for example, stockings can be worn.

Variations in the waxing technique such as sugaring in which an adhesive ball is rolled along the skin to pluck hair therefrom or cold wax adhesive strips which are applied to the skin and then torn away are known but are generally recognised as being less efficient at hair removal than waxing.

Thus there exists a need for a method of hair removal which mitigates some or all of the above-mentioned disadvantages. In accordance with that need the present - invention provides a method of removing hair from skin, the method comprising the steps of:

a) providing a depilatory composition in a pressurised container comprising release means, b) actuating the release means so that the depilatory composition is dispensed from the container, c) applying the depilatory composition to the skin and allowing it to stiffen, and d) removing the depilatory composition from the skin, thereby plucking out the hair.

The term stiffening as used herein is to be understood as a change in the depilatory composition from the workable state in which it is dispensed to a cohesive material which is strong enough to pluck entrained hairs from the skin.

is It is of course important that the depilatory composition does not adhere so strongly to the skin that it cannot be easily removed from the skin. It is also important that the depilatory composition does not adhere so strongly to the skin that the skin is torn away, although it is acceptable for a surface layer of dead cells to be removed. Furthermore, the stiffened depilatory composition has a degree of cohesiveness which is such that it can be removed from the skin largely as a single mass and leaves substantially no residues on the skin.

The depilatory composition may be dispensed from the container as a spray. Use of a spray allows the composition to be applied easily and uniformly to large areas of skin or substrate. Preferably, the depilatory composition is dispensed from the container as a foam or mousse (mousses are foams having a relatively small bubble size and are particularly suited to cosmetic applications). Except where it is clear that the contrary is intended, references herein to "foams" are to be understood as including mousses. That foam or mousse may be applied to the skin directly from the container or it may be first dispensed onto, for example, a spatula and then smeared across the skin. The use of a depilatory composition as a foam has been found in the present invention to have the advantages that foams are soft but not liquid and are easy to work on the skin to provide a layer of desired thickness over a defined area of the skin from which it is desired to remove the hair. The depilatory composition may also be dispensed in other forms, for example, as a gel.

Preferably, the depilatory composition stiffens and is ready for removal in not more than 30 minutes after application to the skin. Advantageously, the depilatory composition stiffens and is ready for removal in not more than 10 minutes after application to the skin. Especially advantageously, the depilatory composition stiffens and is - 7 ready for removal in not more than 3 minutes after application to the skin.

Advantageously, once the depilatory composition has stiffened and is ready for removal from the skin a flexible substrate is applied to the stiffened depilatory composition and the depilatory composition is removed from the skin by pulling the flexible substrate away from the skin.

Preferably, the flexible substrate comprises a sticky coating and especially advantageously the flexible substrate is adhesive tape, for example, in experiments parcel tape has been found to be suitable. Alternatively, the sticky coating can be made simply by applying the depilatory composition to the flexible substrate, for example, to a fabric of the type used in waxing, and allowing it to stiffen.

The flexible substrate may be applied to the smeared depilatory composition before it stiffens. This has the advantage that, in the case where the flexible substrate does not comprise a sticky coating, it is unnecessary to apply one as the depilatory composition will adhere to the substrate as it stiffens. However, this method has the disadvantage that the stiffening time of the depilatory composition may be increased.

Preferably, the depilatory composition is not heated before application to the skin. It is envisaged that the depilatory composition would normally be applied at ambient 8 temperature, as that is convenient and avoids the discomfort associated with application of hot materials.

Preferably, the container and release means are so arranged that there is no return of depilatory composition into the container thereby preventing contamination by bodily fluids. This reduces the risk of the transfer of disease from one person to another by use of the same container of depilatory composition and makes unnecessary the use of more than one spatula per person.

The stiffening may be a result of a chemical reaction, for example a cross-linking or curing reaction, or of the loss of a volatile component or (as in waxing) a change in temperature. Conveniently, the stiffening occurs in the absence of a change in temperature. Preferably, the depilatory composition comprises a volatile component such as water and the depilatory composition stiffens upon evaporation of the volatile component. The use of water as a volatile component avoids the use of smelly or toxic solvents and water is, of course, benign to the skin whilst still allowing the stiffening process to occur in a convenient time, for example, less than 5 minutes.

Surprisingly, it has been found that a commercial contact adhesive, "Affix" (trade mark), manufactured and packaged in aerosol cans by Evode Ltd of Stafford, England is effective in - 9 removing hair from skin when used in accordance with the method of the invention (contact adhesives are primarily used for laminate bonding). Affix foam has the desirable appearance and texture of a mousse. Furthermore, it has also been found that whilst Affix foam remains soft and workable for an extended period of say 30 minutes after being dispensed from the can, when it is smeared into a film of a depth suitable for hair removal the film stiffens more quickly. It has been found that a smeared film of foam up to 0.5mm thick is suitable for removal of hair. Such a film stiffens in about 2% minutes or less, depending on the thickness of the film, whereas a film suitable for removal of especially coarse, thick hair may exceed 0.5mm in thickness and may be, for example, up to 1.Omm thick. A film of Affix of thickness 1.Omm has been found to take approximately 5 minutes to stiffen. This is believed to be because the stiffening takes place on evaporation of water (Affix is water based) which is much more rapid from a thin film of foam than from a thicker mass of foam. Thus a desirable combination of rapid stiffening with a long working time is obtained. It is believed that other depilatory compositions in which stiffening is caused by the evaporation of a volatile component and which are applied as a foam or gel would also have this property. Furthermore, as the Affix stiffens, it changes from an opaque white foam to a transparent colourless - 10 film, thus indicating when it is ready for removal. This change in appearance is believed to be related to the collapse of the foam during the evaporation of the water. Contact adhesives which are suitable for use in the method of the present invention are preferably water based. Advantageously they comprise an aqueous medium containing from 30 to 80 wt.%, for example 45 to 60 wt.%, of solid adhesive components. The adhesive may be based on one or more synthetic polymers, for example, selected from acrylic, styrene-acrylic, styrene- butadiene, vinyl acetate, urethane or chloroprene polymers, or could be based on a naturally-occurring polymer, such as a polymer present in natural latex. If desired, the composition may contain both synthetic and naturally-occurring polymers. A preferred aqueous adhesive copolymer emulsion for use in the method of the present invention is a polychloroprene latex emulsion containing 50 to 60 wt % solids.

Contact adhesives for use in the method of the present invention are preferably dispensed as a foam as is described in W096/14366. The formulation of example 1 of W096/14366 is particularly useful in the method of the present invention. They will preferably comprise an anionic surfactant and an amphoteric surfactant. The anionic surfactant serves to create the surface tension conditions necessary in the liquid to form the foam. The addition of an amphoteric surfactant has been found to produce a time-stable foam in the latex emulsion which contributes to the extended waxability desired above. The amphoteric surfactant also lowers the composition's viscosity. The surfactants may be present at a total of from 0.25 to 10 wt.% dry weight preferably 1 to s wt.% dry weight. The ratio of anionic to amphoteric surfactant may range from 5:1 to 1:5 (as dry weight), preferably 1:3 to 3:1. In order to generate a foam, the contact adhesive will preferably contain from 1 to 10 wtA of a foaming agent. Preferred foaming agents include halocarbons or hydrocarbons. Hydrocarbons such as butanes are preferred. Chemical blowing agents may also be employed, such as inorganic carbonates and inorganic bicarbonates. The contact adhesive preferably contains a tackifier such as a natural or artificial resin or derivative thereof. The tackifier is preferably a rosin ester emulsion and may be present at from 15 to 50% dry weight, most preferably 20 to 25% dry weight.

Affix suffers from the disadvantage, however, that it has not been formulated specifically for use on the human skin. It will be appreciated that the depilatory composition should be dermatologically acceptable. Thus, advantageously, the depilatory composition comprises no allergenic or otherwise irritant components and is suitable for cosmetic use on human skin. Such depilatory compositions are another aspect of the present invention.

- 12 The invention further provides a method of plucking hairs from skin comprising the steps of applying a depilatory composition from a container wherein the arrangement is such that ingress of material into the container is prevented, allowing the depilatory composition to stiffen and then removing the depilatory composition from the skin thereby plucking hairs from the skin.

Preferably the depilatory composition comprises an indicator which indicates when the stiffening process has occurred.

In a further aspect the invention also provides a depilatory package suitable for use in the method described above comprising a container comprising release means, a depilatory composition, and a propellant, wherein the depilatory composition does not irritate the skin in use.

Preferably, the depilatory composition contains one or more additives which render the depilatory process less traumatic, for example, anaesthetics, analgesics, antiinflammatory agents, anti-histamines, antiseptics, vasoconstrictive agents and/or soothing agents. The composition may if desired contain other ingredients customarily employed in compositions for cosmetic use. Advantageously, the depilatory composition contains one or more additives which improve the condition and/or appearance of the skin, for example, emollients, moisturisers, pigmenting agents and/or - 13 essential oils. Preferably, the depilatory composition contains perfume.

Preferably, the depilatory composition is so formulated that the stiffening process is associated with a clear change 5 in the appearance of the depilatory composition.

It is preferred for the components of the composition to be so selected that the pH of the composition is from 4 to 6. A pH in that range is preferred in order for the composition to have good compatability with the skin. The use of materials having a pH outside the range of 4 to 6 can affect the performance of the skin's acid mantle and thus have a detrimental effect on the protective function of the skin.

A method of hair removal according to the invention will now be described by way of example with reference to the accompanying drawings in which:FIGURE 1 shows the depilatory substance being dispensed directly onto a leg; FIGURE 2, in an alternative method to that of Figure 1, shows the depilatory substance being dispensed onto a spatula; FIGURE 3 shows the depilatory substance being spread evenly over an area of hairy skin; FIGURE 4 shows a sticky fabric strip being placed in contact with the stiffened depilatory composition; and FIGURE 5 shows the removal of the fabric strip complete with the depilatory composition and unwanted hair.

- 14 Figure 1 shows a depilatory composition 1 (Affix, a commercially available contact adhesive manufactured by Evode, Ltd, of Stafford, England) being dispensed from a pressurised can 2 via a finger actuated valve 3 (suitable cans and valves are well-known, for example, shaving foam cans). The depilatory composition 1 is forced from the can 2 as a foam mass onto the skin 4 of the leg. In this state, the depilatory composition remains workable for up to thirty minutes.

Figure 2 shows the depilatory composition of Figure 1 being dispensed onto a disposable wooden spatula 5. Alternatively, a purpose designed spatula may be designed to apply a film at desired thickness. The depilatory composition 1 is then spread in a film over the area of the skin from which it is desired to remove hair 6 (Figure 3). After spreading, the film of depilatory composition 1 stiffens to a cohesive film in which the hairs 6 are intimately caught up and entrained. A fabric strip 7 having a sticky coating 8 on one side is placed on top of the film of depilatory composition 1 as is shown in Figure 4 whereupon the sticky coating 8 adheres to the depilatory composition 1.

The fabric strip 7 is then pulled away from the skin 4 in the direction opposite to that of the hair growth. The stiffened film of depilatory substance comes away with the is - fabric strip 7 and takes with it the entrained hairs 6 which are thereby plucked out from the skin 4.

The process may be repeated to remove any remaining hairs. As noted above, this repetition is not possible with 5 waxing.

The above treatment leaves no sticky residue on the skin. It is furthermore believed that the photosensitivity of the skin is not disadvantageously affected.

- 16

Claims

1. A method of removing hair from skin, the method comprising the steps of:

a) providing a depilatory composition in a pressurised container comprising release means, b) actuating the release means so that the depilatory composition is dispensed from the container, c) applying the depilatory composition to the skin and 10 allowing it to stiffen, and d) removing the depilatory composition from the skin, thereby plucking out the hair.

2. A method as claimed composition is dispensed is

3. A method as claimed composition is dispensed A ethod as claimed in claim 1, wherein the depilatory from the container as a spray. in claim 1, wherein the depilatory from the container as a foam. in claim 3, wherein the foam is a

4 mousse.

5. A method as claimed 20 composition is dispensed

6. A method as claimed of the depilatory composition is a one-part formulation.

7. A method as claimed in claim 3, wherein the foam is smeared across the skin before it stiffens.

in claim 1, wherein the depilatory from the container as a gel. in claim 1, wherein the application 17

8. A method as claimed in claim 7, wherein the foam is applied to the skin directly from the container and then smeared across the skin.

9. A method as claimed in any of claims 1 to 8, wherein the depilatory composition stiffens and is ready for removal in not more than 30 minutes after application to the skin.

10. A method as claimed in claim 9, wherein the depilatory composition stiffens and is ready for removal in not more than 10 minutes after application to the skin.

11. A method as claimed in claim 9, wherein the depilatory composition stiffens and is ready for removal in not more than 3 minutes after application to the skin.

12. A method as claimed in any of claims 1 to 11, wherein the depilatory composition remains workable for up to 30 minutes after being dispensed from the container.

13. A method as claimed in any of claims 1 to 12, which also includes the step of applying a flexible substrate to the stiffened depilatory composition and the depilatory composition is removed from the skin by pulling the flexible substrate away from the skin..

14. A method as claimed in claim 13, wherein the flexible substrate comprises a sticky coating.

15. A method as claimed in claim 14, wherein the flexible substrate is sticky tape.

- 18

16. A method as claimed in claim 14, wherein the sticky coating comprises the depilatory composition.

17. A method as claimed in any of claims 1 to 16, wherein the depilatory composition is at ambient temperature when it is applied.

18. A method as claimed in any of claims 1 to 17, wherein the container and release means are so arranged that there is no return of depilatory composition into the container thereby preventing contamination by bodily fluids.

19. A method as claimed in any of claims 1 to 18, wherein the depilatory composition comprises a volatile component.

20. A method as claimed in claim 19, wherein the volatile component is water.

21. A method as claimed in claim 19 or claim 20, wherein the depilatory composition stiffens upon evaporation of the volatile component.

22. A method as claimed in any of claims 1 to 21, wherein the depilatory composition is a contact adhesive.

23. A method as claimed in claim 22 wherein the contact adhesive is 'Affix' manufactured and packaged in aerosol cans by Evode Ltd of Stafford, England.

24. A method as claimed in any of claims 1 to 22, wherein the depilatory composition comprises no allergenic or otherwise irritant components and is suitable for cosmetic use on human skin.

- 19

25. A method of plucking hairs from skin comprising the steps of applying a depilatory composition from a container wherein the arrangement is such that ingress of material into the container is prevented, allowing the depilatory composition to stiffen and removing the depilatory composition from the skin thereby plucking hairs from the skin.

26. A depilatory package suitable for use in the method of any one of claims 1 to 25, comprising a container having release means, a depilatory composition, and a propellant, wherein the depilatory composition does not irritate the skin in use.

27. A package as claimed in claim 26, wherein the container is an aerosol can.

28. A package as claimed in claim 26, wherein the propellant is contained in a refill pack.

29. A package as claimed in claim 26, or claim 28, wherein the release means is replaceable.

30.

31.

A depilatory package as claimed in any of claims 26 to 29, wherein the depilatory composition is a contact adhesive. A depilatory package as claimed in any of claims 26 to 30, wherein the depilatory composition comprises a solvent.

32. A depilatory package as claimed in claim 31, wherein the solvent is water.

-

33. A depilatory package as claimed in claim 31 or 32, wherein, in use, the depilatory composition stiffens through evaporation of the solvent.

34. A replaceable release means suitable for use in the depilatory package of claim 29.

35. A depilatory composition which is suitable for use in the method of claims 1 and 25, or a depilatory package according to claim 26 which comprises no allergenic or otherwise irritant components and is suitable for use on human skin.

36. A depilatory composition as claimed in claim 35, which contains one or more additives which render the depilatory process less traumatic.

37. A depilatory composition as claimed in claim 35 or claim 36, which contains one or more additives which improve the condition and/or appearance of the skin.

38. A depilatory composition as claimed in any of claims 35 to 34, which contains perfume.

39. A depilatory composition as claimed in any of claims 35 to 38, which is so formulated that the stiffening process is associated with a clear change in the appearance of the depilatory composition.

40. A depilatory composition as claimed in any one of claims to 39, in which the components of the composition are so selected that the pH of the composition is from 4 to 6 i