METHOD FOR REMOVING HAIR FROM AN AREA OF SKIN

Abstract

The present invention refers to a method for removing hair from an area of skin by applying a shaving aid composition to the area of skin to be shaved. The shaving aid composition includes water, at least one oil and at least one shear thinning structurant. The area of skin is shaved using a hair removal device comprising a treatment sheet with aperture blades.

Claims

1. A method for removing hair from an area of skin, comprising the step of: (A) applying a shaving aid composition to the area of skin to be shaved, the shaving aid composition comprising water, at least one oil and at least one shear thinning structurant, wherein the shaving aid composition has a polar component of surface free energy of 30 to 80 mJ/m.sup.2, (B) shaving the area of skin to be shaved using a hair removal device comprising at least one treatment sheet with aperture blades.

2. The method of claim 1, wherein the shaving aid composition has a polar component of surface free energy of 40 to 60 mJ/m.sup.2.

3. The method of claim 1, wherein the shaving aid composition has a storage modulus G of 150 to 1500 Pa.

4. The method of claim 1, wherein the shaving aid composition has a contact angle on the surface of the at least one treatment sheet of 100 to 180?.

5. The method of claim 1, wherein the at least one oil is selected from the group consisting of: hydrocarbons, preferably straight, branched, or cyclic alkanes and alkenes having 20 to 65 carbon atoms esters, preferably esters from fatty acids or alcohols, amides, preferably N-acetyl-N-butylaminiopropionate, isopropyl N-lauroylsarcosinate, butylphthalimide, isopropylphthalimide, and N,N,-diethyltoluamide, ethers, preferably saturated and unsaturated fatty ethers of a polyhydric alcohol, and alkoxylated derivatives thereof, silicones, preferably polysiloxanes and mixtures thereof.

6. The method of claim 1, wherein the at least one shear thinning structurant is selected from the group consisting of clays, gums, microgels, super absorbent polymers, gel networks formed from fatty amphiphiles and mixtures thereof.

7. The method of claim 1, wherein the at least one additive is selected from the group consisting of emulsifiers, skin care actives (in particular vitamins, peptides and peptide derivatives, sugar amines), moisturizing agents, conditioning agents, exfoliating agents, antimicrobial agents, antidandruff agents, skin lightening agents (sunless) tanning agents, perfumes, preservatives, chelants, sensates, desquamation actives, anti-acne actives, topical anaesthetics, tanning actives, antimicrobial actives, sunscreen actives, visual skin enhancers minerals, opacifiers, anti-inflammatories, antioxidants, minerals, anti-inflammatories, antioxidants, humectants, particles and mixtures thereof.

8. The method of claim 1, wherein the shaving aid composition consists of: a) 55 to 97% by weight of water, b) 2 to less than 15% by weight of at least one oil, c) 1 to 10% by weight of at least one shear thinning structurant, and d) 0 to 20% by weight of at least one additive, the components a) to d) adding up to 100% by weight of the shaving aid composition.

9. The method of claim 1, wherein the shaving aid composition consists of: a) 60 to 92% by weight of water, b) 5 to 14% by weight of at least one oil, c) 2 to 8% by weight of at least one shear thinning structurant, and d) 1 to 18% by weight of at least one additive, the components a) to d) adding up to 100% by weight of the shaving aid composition.

10. The method of claim 1, wherein the at least one treatment sheet is secured to the head with a frame member that has an opening to expose a cutting zone of the at least one treatment sheet, wherein the frame member is preferably made from bendable non-corrosive metal, preferably aluminum or steel.

11. The method of claim 1, wherein the at least one treatment sheet is a planar sheet with aperture blades located within the cutting zone.

12. The method of claim 1, wherein the at least one treatment sheet has a total aperture area A from 10 to 400 mm.sup.2 and a cutting zone area S in the range from 100 to 800 mm.sup.2 and a transparency T=A/S is in a range from 5 to 60%.

13. The method of claim 12, wherein during shaving the skin contacting surface of the frame member or the cutting zone of the at least one treatment sheet or both are in contact with the skin to be shaved.

14. The method of claim 1, wherein the surface of the frame member and/or the at least one treatment sheet are hydrophobic or coated with PTFE, having preferably a polar component of the surface energy of 0 to 10 mJ/m.sup.2, more preferably from 1 to 5 mJ/m.sup.2.

15. The method of claim 1, wherein the hair removal device comprises 2,3,6,7 or 10 treatment sheets.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0136] FIG. 1 is a perspective view of a hair removal device according to the present invention,

[0137] FIG. 2 is a top view of a treatment sheet in accordance with the present invention,

[0138] FIG. 3 is a cross-sectional view of a hair removal device in accordance with the present invention,

[0139] FIG. 4 is a top view onto the second surface of a treatment sheet in accordance with the present invention,

[0140] FIG. 5a-d are top views onto the second surface of alternative treatment sheets having different shapes in accordance with the present invention,

[0141] FIG. 6a is a diagram showing the surface energy data regarding the contact angle and the polar surface energy component of a first selected shaving aid composition,

[0142] FIG. 6b is a diagram showing the surface energy data regarding the contact angle and the polar surface energy component of a second selected shaving aid composition,

[0143] FIG. 6c is a diagram showing the surface energy data regarding the contact angle and the polar surface energy component of a third selected shaving aid composition,

[0144] FIG. 7a is a diagram showing the rheology data regarding the storage modulus G and the loss modulus G of a first selected shaving aid composition, and

[0145] FIG. 7b is a diagram showing the rheology data regarding the storage modulus G and the loss modulus G of a first selected shaving aid composition.

DETAILED DESCRIPTION OF THE INVENTION

[0146] FIG. 1 is a perspective view of a hair removal device 10 having a head 11 and a handle 30. The head 11 comprising a housing 20 and a frame member 50 attached to the housing 20 and disposed over a treatment sheet 40 with a plurality of aperture blades 430. In this example the treatment sheet 40 and frame member 50 have a hexagonal shape. Other shapes are included in the present invention as shown in FIG. 5 below.

[0147] FIG. 2 shows a circular treatment sheet 40 of the present invention in a top view looking onto the skin contacting surface 41. The treatment sheet 40 comprises aperture blades 430 having a aperture perimeter 431 enclosing the aperture area a.sub.i. The cutting edges 435 are shaped along at least a portion of the aperture perimeter 431 located at the skin contacting surface 41 resulting in an enclosed cutting edge.

[0148] In the hair removal device 10, the frame member 50 is disposed over the treatment sheet and covers the perimeter zone 451 on the skin contacting surface 41 and exposes the cutting zone 60 that is enclosed by the perimeter area 451, i.e., the cutting zone 60 is a portion of the skin contacting surface 41 that is visible when the frame member 50 is attached to the housing 20 of the head 11 of the hair removal device 10.

[0149] FIG. 3 is a cross-sectional view of a head 11 of a hair removal device in accordance with the present invention. The head 11 comprising a frame member 50 disposed over a treatment sheet 40. The treatment sheet 40 comprises a skin contacting surface 41 that is facing the skin surface 90 to be shaved. Similarly, the frame member 50 comprises a surface 51 that is facing the skin surface 90. A portion of the skin contacting surface 41 that is left exposed towards the skin surface 90 through an opening of the frame member 50 is referred to as the cutting zone 60. When used for removing hair from the skin surface 90, a layer of shaving aid 80 flows between the skin surface 90 and the skin facing surfaces 41 and 51 of the hair removal device 10.

[0150] FIG. 4 shows a perspective view of a preferred hexagonal treatment sheet 40 according to the present invention with alternative number and arrangements of octagonal apertures. FIGS. 5a to 5d shows further top views of the first surface of treatment sheets according to the present invention with alternative number and arrangements of circular apertures.

[0151] Consumer Tests

[0152] To assess which shaving aid formulations are preferred in use and which ones are unsuitable, several shaving aid fluids were formulated and assessed during use of the hair removal device shown in FIG. 1. The shaving aids were assessed using the method according to the present invention involving the steps of applying the shaving aid to the skin to be shaved and subsequently removing hair from the skin using the hair removal device shown in FIG. 1. This method was carried out applying the shaving aid directly to dry skin and repeated applying the shaving aid to moist skin after washing the skin prior to using the method according to the present invention.

[0153] The performance of the method was assessed by the test candidates on a five-point scale (5=very good, 1=poor) for several shaving attributes including the overall performance of the shave, closeness of the shave, hair removal efficiency, lubrication during the shave, comfort, and safety of the shave. Shaving aids that are preferred reached an average score greater than 3, while unsuitable shaving aids received an average score of 3 or below.

[0154] The relative content of water, oil and structurants of the different shaving aid fluids that were tested are given in Table 1. The fluids A to C were rated higher than 3 for overall performance of the shave and are therefore preferred for the method of the current invention Shaving aid fluids D to E were rated 3 or below for overall performance of the shave and are therefore not suitable for the method of the current invention.

TABLE-US-00001 TABLE 1 Shaving Water Oil Structurant Additives aid % % % % A 73 11 2 14 B 87 2 7 4 C 73 6 3 18 D 77 2 0.5 19.5 E 91 0 0 9 F 69 0 0 31

[0155] The shaving aids have been prepared by the following methods: [0156] Formula A: [0157] 1. In pot A, add water and heat to 75? C. [0158] 2. Add surfactants, chelants, polymers and humectants. [0159] 3. In pot B, add oils and fatty alcohols and heat to 75? C. [0160] 4. Add pot B to pot A and homogenise [0161] 5. Neutralise with Sodium hydroxide [0162] 6. Cool to 40? C. [0163] 7. Add preservatives, perfume and vitamin. [0164] Formula B: [0165] 1. In pot A, add water and heat to 75? C. [0166] 2. Add surfactants, fatty alcohols, chelants, polymers and humectants. [0167] 3. In pot B add oils and heat to 75? C. [0168] 4. Add pot B to pot A and homogenise. [0169] 5. Cool to 40? C. [0170] 6. Add preservatives and perfume. [0171] Formula C: [0172] 1 In pot A, add water and heat to 75? C. [0173] 2. Add chelants and humectants [0174] 3. In pot B, mix surfactants oils and fatty alcohols and heat to 75? C. [0175] 4. Add pot B to pot A and homogenise [0176] 5. Cool to 40? C. [0177] 6. Add preservatives, silicones, starches, perfume and vitamin. [0178] Formula D: [0179] 1. In pot, mix water, polymers and sorbitol, then heat to 60? C. [0180] 2. Add surfactants, heat to 80? C. [0181] 3. Add TEA [0182] 4. Cool to 40? C. [0183] 5. Add oils, glycerin, preservatives and perfume [0184] 6. Concentrate combined with blowing agents and packed. [0185] Formula E: [0186] 1. In pot, mix water and hydroxyethyl cellulose then heat to 75? C. [0187] 2. Add surfactants, chelants, polymers and humectants [0188] 3. Cool to 40? C. Add preservatives and perfume. [0189] Formula F: [0190] 1. In pot, add water and heat to 75? C. [0191] 2. Add surfactants, chelants, polymers and humectants. [0192] 3. Cool to 40? C. Add preservatives and perfume and vitamin.

[0193] A detailed list of the ingredients of the shaving aids that were tested are given in Table 2.

TABLE-US-00002 TABLE 2 ingredient A B C D E F water water 72.9 86.4 72.5 76.9 91.4 69.3 oil iso-hexadecane 3.0 iso-propyl iso-stearate 1.3 iso-propyl palmitate 7.5 dimethicone 1.0 1.5 1.0 amodimethicone 0.5 petrolatum 1.6 mineral oil 0.88 glyceryl oleate 1.8 structurant bethenyl alc. 0.4 0.60 cetyl alc. 0.88 1.0 0.90 stearyl acl. 0.88 2.9 1.1 sodium polyacrylate 0.12 0.40 starch carbomer 0.16 hydroxyethylcellulose 0.5 behentrimonium methosulfate 3.0 additive isopentane 2.5 isobutane 0.8 disodium EDTA 0.05 0.13 0.1 0.12 Steareth 2 0.25 Steareth 21 0.5 polyquatemium 0.25 cetyl betaine 4.4 1.0 glycerin 4.0 3.0 7.1 1.0 2.0 hexanediol 0.80 1.17 0.80 PEG-200 0.10 4.7 PEG-90M 0.10 sorbitol 0.68 2.9 decyl glucoside 0.48 parfume 0.30 0.20 0.01 0.20 tapioca starch 5.0 citric acid 0.03 0.6 sodium hydroxide 0.21 preservatives 0.48 0.38 0.05 0.48 hexylene glycol 6.0 myristic Acid 0.06 palmetic acid 9.2 stearic acid 0.11 0.10 1.3 sodium lauryl sulfate 2.4 sodium lauroamphoacetate 9.7 sodium lauroyl sarcosinate 5.0 sodium trideceth sulfate 5.0 vitamin 0.10 5.5 0.25

[0194] FIGS. 6a to 6c are diagrams that illustrate the surface property data of selected shaving aids that were tested in use. Solid black circles represent shaving aids that were preferred in use over shaving aids that were found unsuitable in use represented by open circles. FIG. 6a shows the polar component to the surface free energy in milli Joule per meter squared for preferred and unsuitable shaving aids and also for skin (diamond symbol) and for surfaces of solid materials of the hair removal device (crosses).

[0195] Shaving aid D represents a typical shaving aid used with conventional hair removal devices that contains a plurality of straight linear blades. Shaving aid D was not liked when used with the shaving device of the present invention containing a treatment sheet with a plurality of cutting apertures. For the method of the present invention, shaving aid D was too thin and did not provide sufficient lubrication and cushioning between the skin and treatment sheet surfaces. This is because for shaving aid D, as can be seen from FIG. 6, the polar component of surface energy and the contact angles of the shaving aid on the surfaces of the device and the skin were too low compared to the preferred shaving aids. The higher polar component of surface energy and contact angles of the preferred shaving aids are required to form fluid droplets between the shaver and skin surface, which generate the required ball bearing-like lubrication mechanism and a cushioning layer of the shaving aid composition between the 2 surfaces.

[0196] It can clearly be seen that preferred shaving aids have a polar component to the surface free energy greater than about 40 mJ/m2. FIG. 6b shows the contact angle in degrees for preferred and unsuitable shaving aids when deposited on the treatment sheet of the hair removal device. It can clearly be seen that preferred shaving aids have a contact angle on the surface of the treatment sheet greater than about 100?. FIG. 6c shows the contact angle in degrees for preferred and unsuitable shaving aids when deposited on skin of the hair removal device. It can clearly be seen that preferred shaving aids have a contact angle on the skin surface greater than about 80?.

[0197] FIGS. 7a and 7b are diagrams that illustrate the rheology properties of selected shaving aids that were tested in use. Solid black circles represent shaving aids that were preferred in use over shaving aids that were found unsuitable in use represented by open circles. FIG. 7a shows the storage modulus G measured in Pascal for preferred and unsuitable shaving aids. FIG. 7b shows the loss modulus G measured in Pascal for preferred and unsuitable shaving aids.

[0198] Shaving aid D represents a typical shaving aid used with conventional hair removal devices that contain a plurality of straight linear blades. Shaving aid D was not liked when used with the shaving device of the present invention containing a treatment sheet with a plurality of cutting apertures. For the method of the present invention, shaving aid D was too thin and did not provide sufficient lubrication and cushioning between the skin and treatment sheet surfaces. This is because for shaving aid D, as can be seen from FIG. 7, the storage and loss modulus are too low compared to the preferred shaving aids. The higher storage and loss modulus of the preferred shaving aids are required to form a cushioning layer of the shaving aid composition between the device surface and the skin surface.

[0199] It can clearly be seen that preferred shaving aids have a storage modulus greater than about 150 Pascal. It can clearly be seen that preferred shaving aids have a loss modulus greater than about 50 Pascal.

[0200] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as 40 mm is intended to mean about 40 mm or ?10% of the disclosed dimension.

[0201] Every document cited herein, including any cross referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests, or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0202] While particular embodiments of the present disclosure have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.