Method for assessing hair

Abstract

A method for assessing damage of hair by releasably engaging a first end of hair fibres with a holding device so that an opposite, second end of said hair fibres hangs free and applying sufficient force to the second end of the hair fibres such that the hair fibres at the first end are pulled across the holding device; wherein the hair has at least two sections of different levels of damage along its length wherein the at least two sections of different levels of damage comprises damage that is provoked by applying damaging treatment to the hair; and wherein the force required to pull the hair through each section is used to determine the damage to the hair.

Description

[0001] METHOD FOR ASSESSING HAIR

[0002] The present invention relates to a method for assessing the level of damage of hair fibres, the efficacy of treatment compositions on said fibres and methods for assessing and comparing the efficacy of treatment compositions on hair.

[0003] WO2014 / 117907 discloses a method for assessing the state of hair by releasably engaging a first end of hair fibres with a holding device which so that an opposite, second end of said hair fibres hangs free and applying sufficient force to the second end of the hair fibres such that the hair fibres at the first end are pulled from the holding device.

[0004] WO 2018 / 099715 discloses a method for assessing the state of hair by releasably engaging a first end of hair fibres with a holding device so that an opposite, second end of said hair fibres hangs free and applying sufficient force to the first end of the hair fibres such that the hair fibres at the second end are pulled across the holding device, wherein the force is in an upwards direction and applied by action of an encapsulated gas having a density of less than that of air.

[0005] Evans et al; Evaluating Hair Conditioning with Instrumental Combing, Cosmetic & Toiletries Magazine, vol 126 no. 8, 1 August 2011, pp558-563 discloses the use of instrumental combing measurements in the formulating of hair conditioning products, hair tress can be pulled through a comb to evaluate the combing force. The force is increased during the method as the hair is mechanically pulled through the comb at constant speed.

[0006] Despite the prior art there remains a need for improved methods for measuring and demonstrating the damaged nature of hair fibres.

[0007] We have found that as hair is increasingly damaged it becomes rougher and less manageable.

[0008] The hair fibre is susceptible to damage from a number of sources. These include environmental factors such as excessive exposure to UV; chemical factors for example oxidative processes such as bleaching, and dyeing as well as reductive processes such as perming or straightening; temperature factors such as the use of heated styling appliances, and mechanical factors such as combing and brushing. Over time, the cumulative effect of these damaging factors may progressively damage the hair fibre.

[0009] Consumers are often not aware of the level of damage along the full length of the hair fibres. For example, the tip area of hair can become more heavily damaged as it is subjected to damaging treatments over a longer period of time. Areas where damage occurs or damaging treatments are applied multiple times can result in patches or areas of varying damage along the length of the hair. Repeated damaging treatments can result in highly damaged areas.

[0010] For example, bleaching is a treatment that can cause damage to hair. It is known that deposition of conditioning agents is reduced on bleached hair. Bleached hair is known to be particularly poor at retaining silicones during and after application, leading to low levels of deposition and inadequate benefit to the user. The user, therefore, has to apply more product and may never reach the level of conditioning that is desired. Indeed, we have found that measured silicone levels delivered to bleached hair can be less than 20 % than that achieved for the same product used on virgin hair. One characteristic of bleaching is that the oxidation removes 18-Methyl Eicosanoic Acid (18-MEA) from the hair surface, hence the hair surface becomes significantly hydrophilic. Accordingly, deposition of benefit agents onto the surface of bleached hair is different from deposition onto non-bleached hair, which is hydrophobic. Further, interaction of a treatment with bleached hair is different from interaction with hair damaged with non-bleach chemicals.

[0011] Definition of the invention

[0012] Accordingly, and in a first aspect, there is provided a method for assessing the level of damage of hair by providing hair fibres and releasably engaging a first end of hair fibres with a holding device so that an opposite, second end of said hair fibres hangs free and applying sufficient force to the second end of the hair fibres such that the hair fibres at the first end are pulled across the holding device, wherein the hair has at least two sections of different levels of damage along its length, wherein the at least two sections of different levels of damage comprises damage that is provoked by applying damaging treatment to the hair; and wherein the force required to pull the hair through each section is used to determine the damage to the hair.

[0013] General Description

[0014] The holding device is a device that is capable of releasably engaging hair fibres. The holding device is a device. The holding device is not part of a living being such as human hands or fingers.

[0015] Preferably, the holding device comprises bristles or tines. More preferably, the holding device is selected from a hair brush and a comb, most preferably a brush. Where the holding device is a brush, it is preferably a round barrelled hair brush.

[0016] Where the holding device comprises bristles or tines, it is preferred that the hair fibres are pulled across the bristles or tines as force is applied to the first end. More preferably, the holding device comprises bristles or tines which extend in a direction away from the direction of applied force.

[0017] Preferably, the holding device comprises bristles or tines and the hair fibres are pulled across the bristles or tines as force is applied to the second end.

[0018] Preferably, the force is applied in a direction away from the holding device.

[0019] The minimum force required to pull the hair through each section is used to determine the damage to the hair.

[0020] The method comprises recording the force applied for moving the hair switch. The speed that the hair moves across the holding device when force is applied may be recorded.

[0021] Preferably, the method further comprises comparing the force applied to one hair switch with the force applied to another hair switch required to achieve the same or comparable movement.

[0022] In one embodiment, the friction arising when the hair fibres are pulled across the holding device is recorded. Preferably, the force is sufficient to pull the hair across the holding device. The force may be sufficient to pull the hair completely from the holding device.

[0023] Preferably, the force is applied by attaching mass to the second end of the hair fibres.

[0024] The method provides an easily demonstrable approach to assessing the level of damage of the hair, particularly along the length of the hair. Preferably the level of damage is measured by the state of tanglement of the hair fibres and / or the level of friction on the surface of the hair.

[0025] Preferably, the force is applied in a progressive manner, i.e. the first force applied is preferably insufficient to pull the hair fibres across the holding device but further or greater force is applied until a point is reached when the hair fibres are pulled across the holding device.

[0026] Preferably, a clip is attached to the second end of hair fibres and weights are added progressively to the clip.

[0027] Preferably, the holding device is a brush or comb. More preferably, the holding device comprises bristles or tines which extend in a direction away from the direction of applied force. Preferably, the bristles or tines extend in a direction opposite to that of the gravitational force.

[0028] The Hair

[0029] The hair for use in the method is preferably a bundle of multiple fibres,

[0030] Preferably, the hair fibres are in the form of hair switches and are preferably from 1 to 10g switches, more preferably 1.5 to 7g switches.

[0031] Preferably the switches are from 10 to 50 cm in length, more preferably from 15 to 30 cm in length and most preferably from 20 to 28 cm in length.

[0032] The hair has different levels of damage along its length, at least 2 different levels, preferably from 2 to 5 different levels. Preferably the levels are sections progressively increasing or decreasing in severity of damage. For example, the hair may be in virgin condition at a section at the first end, next to a section of hair that has been subjected to a damaging treatment once, next to a section of hair that has been damaged twice, next to a section of hair that has been damaged thrice, next to a section of hair that has been damaged four times at the second end. For example a 25 cm (10 inch) hair switch, with each section being about 5 cm (2 inches) in length.

[0033] The damage is caused by a means selected from mechanical means, chemical means, temperature means, environmental means and mixtures thereof.

[0034] Environmental damage can be caused by for example exposure to UV light; chemical damage can be caused by for example oxidative processes such as bleaching or dyeing, reductive processes such as perming or straightening; temperature means includes for example application of heat by blow drying, heat shaping such as curling wands, straighteners, heated rollers, and the like, and mechanical means includes for example repeated combing and brushing.

[0035] Preferably the damage is caused by chemical means, more preferably oxidative damage, most preferably bleaching.

[0036] Preferably the damage results in an increase in friction of the hair.

[0037] The at least two sections of different levels of damage comprises damage that is provoked by applying damaging treatment to the hair.

[0038] Before treatment, the hair itself, in its original state will have an intrinsic level of “background damage”, due to historical exposures of the hair to previous treatment and / or by wear and tear sustained by exposure to daily weather and hair care regimes. This will vary with age and type and treatment of the hair. The sections of different levels of damage may include hair that is in its original state. This provides a useful comparison of the hair before and after treatment within the method of the invention.

[0039] Damage can be provoked by applying a damaging treatment, such as those listed herein above, to hair, to produce damaged hair. The application of damage can be repeated on a section of the damaged hair to produce a section of greater damaged hair. Part of the greater damaged hair can optionally be damaged again to produce a section of even greater damaged hair, and so on as desired.

[0040] An example of such a method of causing, or “provoking” damage is:

[0041] Hair may be be subjected to a damaging treatment for example bleach (any suitable damage treatment can be used). A bottom portion (for example 20 cm (ca. 8 inches) of a 25 cm (ca. 10 inch) length of hair can be bleached for, for example 30 min. Hair is then rinsed with water and dried. This procedure is then repeated on the same hair on the bottom 15 cm (ca. 6 inches) to produce twice bleached hair and optionally repeated again on the bottom 10 cm (4 inches) to produce thrice bleached hair and optionally repeated again on the bottom 2.5 cm ( 1 inch) of the switch to a produce 4 times bleached section of hair, and so on. The length, strength, and type of treatment can be varied. In this method, a section of hair may be included that is left in its original state.

[0042] Weights are added until the hair moves across the holding device. As the hair reaches a section of higher damage, the speed of the movement of the hair across the holding device will slow or even stop. More weights can be added each time the hair stops until it moves across the holding device again. In this way the level of damage can be determined across the different sections along the length of the hair. The damage is determined by the minimum weight required to pull the switch through each progressively damaged section. Damage can be assessed relative to an area of the hair that has not been subjected to damage causation / provocation. Alternatively, a measure of the force required to move the hair over the holding device, before any damage is caused, may initially be carried out. Damage may then be caused to the hair and the extent of the damage, assessed relative to the initial measurement, may be determined.

[0043] The efficacy of any treatment applied to the hair can also be assessed by measuring how far and / or how quickly the hair moves across the holding device, and to what section of level of damage is reached, before and after the application of the treatment. This can be compared to how far hair treated with a different treatment moves and what section of level of damage is reached. In this way, it can be determined that different treatments are capable of moving the hair across different sections of damage before the hair reaches a section of damage that movement stops.

[0044] In the context of this invention, by virgin hair is meant hair that has not been subjected to intensive physical and / or chemical treatment, for example, bleaching, dyeing, perming, reducing treatment, heat treatment and strong and / or prolonged exposure to solar radiation; nor displays features characteristic of damaged hair, for example, split ends and / or excessive dryness and / or increased surface friction compared with hair that has sustained low level damage. Virgin hair includes hair that has sustained low levels of damage during the natural hair life cycle. Sources of low level damage likely include but are not necessarily limited to, washing, brushing, combing and natural processes such as limited solar photo-degradation for example. That is to say no intensive physical and / or chemical treatment has been applied.

[0045] A camera may be used to capture the movement and time the progression of the hair across the holding device.

[0046] Preferably the hair is dry. The hair can be heat dried or air dried, preferably air dried, most preferably blow dried or dried naturally.

[0047] Preferably, the hair is treated with a conditioning composition and preferably dried before the hair is attached to the holding device. This allows the operator to assess the efficacy of the conditioning composition by recording the mass required to pull the hair fibres across the holding device.

[0048] Preferably the applied conditioning composition is a rinse-off conditioning composition.

[0049] In addition, it is apparently clear to those skilled in the art that there is no obstacle to use the present invention for assessing the state of wet hair. Those skilled in the art would be able to measure the force required to pull the wet hair across the holding device.

[0050] Generally, greater force and / or longer time to pull might be required than assessing dry hair. But it is still within the scope of invention. In a second aspect there is provided a method for measuring the conditioning efficacy of a conditioning composition by applying a conditioning composition to hair, allowing to dry and releasably engaging the hair with the holding device and then measuring the force required to pull the hair across the holding device.

[0051] In a third aspect there is provided a method for comparing the conditioning efficacy of at least two conditioning compositions by performing the method of the second aspect on the treated hair samples.

[0052] Preferably, the method of comparing the conditioning efficacy of at least two treatment compositions, preferably treatment compositions, is conducted on the treated hair samples. This may be done by conducting the method consecutively for hair switches treated with different compositions, or simultaneously with the treated switches side by side to each other.

[0053] This allows the operator to immediately determine superiority of one composition over another without the need to measure the mass involved or the time taken to pull the hair through the holding device.

[0054] The method as described may also comprise a step of capturing one or more images of the weights and hair, including CAD images. The images may be stored and / or transmitted for display on one or more visible display units. The display unit is preferably a screen.

[0055] Figure 1 shows a cylindrical brush (1) with radially extending bristles (2). Two hair switches (3X and 3Y), are attached over the brush (1) such that they hang loose. The hair switches have sections of differing damage (A and B). At the loose end of each of the switches is a clip (4) with weight (5) depending therefrom. Switch A is pulled more easily across the cylindrical brush than switch B. Switch B has stopped moving at a section of damage whilst Switch A has moved beyond the section of damage that Switch B has stopped at. Figure 2 shows a hair switch (3Z), with a clip (4) at the first end, that has been progressively damaged along its length in sections A-E, where A = not damaged, B = 1 time damaged, C = 2 times damaged, D = 3 times damaged and E = 4 times damaged.

[0056] EXAMPLE 1

[0057] The hair used was dark Brown European hair in switches of 5g weight and 25 cm length held at one end with a wide clip.

[0058] The hair switches were damaged in sections A-E, where A = virgin, B = 1 x bleached, C = 2 x bleached, D = 3 x bleached and E = 4 x bleached.

[0059] Hair was subjected to a typical bleach treatment before being treated with conditioning compositions as described below. The bottom 8 inches of each switch of hair was bleached for 30 min with Universal Bleach Powder (ex Bright International Corp) and 40 ‘vol’ Creme Peroxide Developer (ex Bright International Corp) (12g of Powder mixed with 24g Creme Peroxide per switch- a ratio of Creme Peroxide: Powder 2:1). Hair was then rinsed with water for 2 minutes and dried. This procedure was repeated on the same hair switch on the bottom 6 inches to produce twice bleached hair and repeated again on the bottom 4 inches to produce thrice bleached hair and finally repeated again on the bottom inch of the switch to a produce 4 times bleached section of hair.

[0060] Switches were treated with the following commercially available hair treatments:

[0061] Switch 1: Dove Bond Strength Shampoo + 10-in-1 Bond Strength Serum mask

[0062] Switch 2: Olaplex No 4 Shampoo + Olaplex No 8 Bond Intense Moisture Max

[0063] The hair was first treated twice with the shampoo as follows:

[0064] 1. 0.5g was applied to the switch and washed for 30 seconds, rinsed for 30 seconds

[0065] 2. 0.5g was applied to the switch and washed for 30 seconds

[0066] The Serum mask or Intense Moisture Max products were then applied as follows

[0067] 1. 1g of formulation was weighed and applied to the switch for 30 seconds, then rinsed for 1 minute. The hair was allowed to dry.

[0068] Method of invention: One end of the switch (Switch 1 or Switch 2) was attached to a cylindrical brush and the other end was left to hang freely.

[0069] A bulldog clip was attached to the free hanging end of the hair fibres and a weight attached to the clip.

[0070] Further weights were added to the clip until the hair switch began to move across the brush.

[0071] Weights were added in a manner such that the minimum weight added required to pull the switch through each progressively damaged section could be recorded.

[0072] Weights (20 g) were added to the second end of the switch. At 80 g Switch 1 fell all the way through the holding device. At this weight, Switch 2 stopped at the twice bleached hair section.

[0073] Hair switch 2 became stuck when movement could not be restarted, even with the addition of multiple further weights.

Claims

CLAIMS1. A method for assessing damage of hair by providing hair fibres (3) and releasably engaging a first end of the hair fibres with a holding device (1) so that an opposite, second end of said hair fibres hangs free and applying sufficient force (5) to the second end of the hair fibres such that the hair fibres at the first end are pulled across the holding device; wherein the hair has at least two sections of different levels of damage along its length; and wherein the at least two sections of different levels of damage comprises damage that is provoked by applying damaging treatment to the hair; and wherein the force required to pull the hair through each section is used to determine the damage to the hair.

2. The method as claimed in claim 1 , wherein the hair has from 2 to 5 sections of different levels of damage along its length.

3. The method as claimed in claim 1 or claim 2, wherein the damage is caused by a means selected from mechanical means, chemical means, temperature means, environmental means and mixtures thereof.

4. The method as claimed in claim 3 wherein the damage results in an increase in friction of the hair.

5. The method as claimed in any preceding claim wherein an application of damaging treatment provides a section of damaged hair and an application of damaging treatment is repeated on part of the section of the damaged hair to produce a section of greater damaged hair and optionally part of the section of greater damaged hair is optionally damaged again to produce a section of even greater damaged hair.

6. The method as claimed in any preceding claim, wherein the hair is dry.

7. The method according to any preceding claim wherein the hair is treated with a conditioning composition prior to engaging to the holding device.

8. The method according to claim 7 wherein the composition is a rinse-off conditioning composition.

9. Method for measuring or demonstrating the conditioning efficacy of a conditioning composition by performing the method of claim 6 and then measuring the force required to pull the first end across the holding device.

10. Method for comparing or demonstrating the conditioning efficacy of at least two conditioning compositions by performing the method of claim 7 on the treated hair samples.

11. Method according to claim 7 wherein the method of claim 7 is conducted simultaneously or consecutively on the treated hair samples.

12. Method according to any preceding claims, which further comprises a step of capturing one or more images of the force and hair as described in claims 1-11 and storing and / or transmitting the images.

13. Method according to claim 12, wherein the one or more images is displayed on one or more visible display units.

14. Method according to claim 13, wherein the display unit is a screen.

Images