Method for evaluating hair fibers
The method extends and measures hair fibers to evaluate shrinkage and elasticity, generating a score for comparing cosmetic treatments, addressing the inadequacies of existing methods in characterizing textured hair styling.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-08-18
- Publication Date
- 2026-04-03
AI Technical Summary
Existing methods for evaluating and improving hair styling processes, particularly for textured hair like African hair, are inadequate in accurately characterizing shrinkage, softness, and suppleness, leading to inefficiencies in styling and longevity of hair extensions.
A method involving extending hair fibers to a predefined length, allowing them to spontaneously recurle, measuring the restoring force over time, and generating a score representative of hair shrinkage, which can be used to evaluate and compare the impact of cosmetic treatments on hair fibers.
Provides a quantitative assessment of hair shrinkage and elasticity, enabling effective comparison of cosmetic treatments to maintain hair elongation and improve styling efficacy.
Smart Images
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Abstract
Description
Title of the invention: Method for evaluating hair fibers
[0001] The present invention relates to a method for evaluating hair fibers and comparing the effects of compositions on hair fibers. CONTEXT
[0002] Textured hair, especially very curly hair and kinky hair such as African hair, is known to be the most difficult hair to style because of its tight curls.
[0003] To facilitate styling textured hair, it is sometimes combed when dry, which leads to breakage. Moreover, once combed, the hair rarely reaches the desired length and instead remains the same length.
[0004] Mechanical extensions are often used to improve hair manageability through braiding. This is a heatless extension routine that reduces the tightness of the curls and the level of tangling. However, this routine is very time-consuming, and the benefits are not lasting because the hair returns to its original state after being exposed to humidity or after experiencing mechanical compression, for example, during sleep or when touched.
[0005] Furthermore, hair straightening, whether chemical or thermal, also improves ease of styling.
[0006] In order to better identify or improve the processes to facilitate styling, it is important to better characterize the hair, in particular its softness and / or suppleness.
[0007] It is therefore desirable to have a hair evaluation process that accurately represents the real behavior of hair fibers in the daily lives of consumers, particularly when it comes to textured hair such as African hair, especially in order to evaluate the shrinkage of hair after extension, its softness and / or its suppleness. Summary of the invention
[0008] Illustrative embodiments of the invention are intended to meet this need and relate to a method for evaluating hair fibers, comprising:
[0009] a) The extension of hair fibers to a predefined length,
[0010] b) Allowing said hair fibers to spontaneously recurle,
[0011] c) The measurement of a restoring force over time during the re-looping of the hair fibers.
[0012] Hair fibers can be textured, like African hair. The terms "textured hair" refer to wavy hair, curly hair, very curly hair such as frizzy hair or kinky hair.
[0013] In steps a) and b), the hair fibers subjected to said steps are preferably textured hair fibers, such as African hair fibers. The hair fibers may be identical or different but belong to the same hair or to a plurality of hairs belonging to the same category, for example, the African hair category. The hair fibers may belong to certain strands of hair, preferably taken from the same person or from different people with the same hair type. Although it is preferable to perform the measurements on strands of hair that have been taken from the head, it is also possible to perform the measurements to evaluate hair at a point of sale or in a hair salon using certain appropriate measuring devices.
[0014] The method according to the invention is better suited to characterize the shrinkage of hair after extension of hair fibers, in particular textured hair fibers such as African hair fibers.
[0015] In an embodiment given by way of example, the invention provides a method for evaluating hair fibers, comprising:
[0016] a) The extension of hair fibers to a predefined length, while measuring the extension force of the hair fibers elongated to said predefined length,
[0017] b) Allowing said hair fibers to spontaneously recurle,
[0018] c) The measurement of a restoring force over time during the re-coiling of the hair fibers,
[0019] d) The generation of a score representative of hair shrinkage after extension, at least on the basis of said measurement of step c),
[0020] e) The generation of information representative of the impact of an optional treatment of hair fibers on hair shrinkage after extension on the basis of said score generated in step d).
[0021] Step c) may include quantifying the return to the spring state after extension of the capillary fibers.
[0022] Step c) can be carried out using an extensometer. The extensometer can be, for example, a Lloyd® extensometer.
[0023] In the extensometer, the hair fibers are pinched at the root and tip. The hair fibers are elongated to a predefined length in step a), then allowed to spontaneously re-loop in step b). The change in the restoring force over time is measured during the re-looping of the hair fibers in step c).
[0024] The method may further include measuring the extension force during the implementation of step a) of extending the hair fibers to a predefined length.
[0025] The measurement in step a) can be carried out using a strain gauge. The strain gauge can be, for example, a Lloyd® strain gauge. The strain gauge can be identical to the one used for the implementation of step c).
[0026] In the extensometer, the capillary fibers are pinched at the root and tip. The handles of the extensometer can be lowered to a defined position, then stretched linearly to a predefined length, and the extension force is measured, at the desired elongation, once or several times, for example four times.
[0027] This measurement in step a) can be used to assess the uncurling strength of curly hair fibers. This gives an indication of the hair's elasticity.
[0028] Said extension force can be measured at different predefined lengths.
[0029] The process may further include the treatment of the hair fibers before the implementation of steps a) to c).
[0030] The treatment of hair fibers may include the application of a cosmetic composition to said hair fibers.
[0031] The process may include the following step:
[0032] d) The generation of a score representative of hair shrinkage after extension, based at least on said measurement of step c).
[0033] This score allows us to obtain a scale for comparing hair shrinkage after extension, which allows for future comparisons.
[0034] Hair fiber shrinkage can decrease when an appropriate composition is applied to the hair fibers, and the rate of shrinkage can be slower compared to natural hair fibers, for example.
[0035] The process may further include generating information representative of the impact of said composition on hair shrinkage after extension based on said score generated in step c).
[0036] This information can make it possible to compare the effects on hair shrinkage, after extension, of different cosmetic treatments, for example of different cosmetic compositions.
[0037] Information representative of the score may be printed or displayed on an information medium, in particular a leaflet, the packaging of a hair composition, an information or advertising panel, a sales brochure, a television screen or a mobile phone screen.
[0038] The score can be compared to a threshold or to a score associated with another cosmetic composition.
[0039] According to another aspect of the invention, a method for comparing the effects on hair shrinkage, after extension, of at least two cosmetic treatments is proposed, comprising:
[0040] - Performing a first treatment on hair fibers,
[0041] - The generation of a score representative of hair shrinkage after extension hair fibers by implementing the process described above,
[0042] - Performing a second treatment on the hair fibers,
[0043] - The generation of a score representative of hair shrinkage after extension hair fibers by implementing the process described above,
[0044] - Comparison of scores.
[0045] The first and second treatments may include the application of the respective first and second compositions to the hair fibers.
[0046] This allows for a comparison of the first and second compositions and helps identify which composition will allow the hair fibers to remain elongated longer. This provides an indicator of the composition's stability and an original way to quantify shrinkage in vivo rather than visually.
[0047] The compositions may be a relaxer or a straightener.
[0048] Other embodiments of the invention relate to a method for manufacturing a hair composition, in which several candidate compositions are provided, the candidate compositions are compared by applying the comparison method described above and the best is selected at least on the basis of the result of the comparison, then the selected candidate composition is mass-produced.
[0049] The manufacturing process may include comparing the scores of the candidate compositions and selecting the one with the lowest score. The manufacturing process advantageously selects the candidate composition that causes the least shrinkage of the hair fibers after extension. Brief description of the drawings
[0050] The accompanying drawings, which are incorporated into and form an integral part of the specification, illustrate currently preferred embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:
[0051] [Fig.la] [Fig.lb] [Fig. 1-c] Figures la, 1b, le are a diagram of an embodiment of a process according to the invention,
[0052] [Fig.2] Fig.2 is a graph showing the evolution of the extension force in newtons as a function of the extension length,
[0053] [Fig. 3] Fig. 3 is a graph illustrating the evolution over time (in minutes) of the restoring force in newtons after extension of two samples of hair fibers, and
[0054] [Fig.4] Fig.4 is a graph illustrating the evolution over time (in minutes) of the restoring force in newtons after extension of the hair fiber samples of [Fig.3] after applying a cosmetic composition.
[0055] In accordance with the invention, and as generally implemented, a method according to the present invention is proposed for evaluating hair fibers. In the illustrated embodiment, the hair fibers correspond to textured hair, such as African hair.
[0056] First, in a step a) an extension of the hair fibers to a predefined length is carried out using an extensometer 1.
[0057] To this end, as illustrated in [Fig. 1a], the capillary fibers H are placed in the extensometer 1. As illustrated, the capillary fibers H are pinched at the root and the tip.
[0058] The handles 15 of the extensometer 1 are then lowered to a defined position, and then stretched linearly to a predefined length, as illustrated in [Fig.lb],
[0059] Step a) consists of measuring an extension force FE at the desired extension, once or several times, for example four times tE4, as illustrated in [Fig. 2]. In the illustrated embodiment, the extension force FE is measured for several samples SI at S10 at different lengths, corresponding respectively to 10%, 20%, 30%, and 50% of the predefined length extension. In this embodiment, the extension force varies between 0.9 N and 1.15 N.
[0060] The measured extension forces are then used for treatment. Based on this measurement, the uncurling force of the curled hair fibers is evaluated. This can provide an indication of the hair's elasticity.
[0061] The process further includes a step b) of allowing said capillary fibers H to spontaneously re-loop, as illustrated in [Fig. 1]. During the re-looping of the capillary fibers H, a step c) of measuring the restoring force FR over time is carried out using the extensometer 1. The restoring force FR makes it possible to quantify the return to the spring state after extension of the capillary fibers H.
[0062] An example of the measurement of the restoring force for two hair samples SA and SB is illustrated in [Fig.3].
[0063] The FR recoil force is provided for the treatment. In particular, based on the FR recoil force, a score representing hair shrinkage after extension, based at least on said measurement from step c), is generated. In the illustrated embodiment, said score corresponds to the shrinkage rate, which quantifies the difference in length between the hair length at step a) and the hair length at step b) after recurling.
[0064] For example, the shrinkage rate for the SA hair sample corresponds to 0.57 while it corresponds to 0.56 for the SB hair sample.
[0065] The process as described above can also be useful for evaluating the impact of hair compositions on hair fibers.
[0066] To this end, the process includes, before step a), a step i) in which the hair fibers are treated by applying a cosmetic composition to said hair fibers.
[0067] Fig. 4 illustrates the evolution of the FR restoring force over time after applying a cosmetic composition to the SA and SB hair samples.
[0068] For example, the shrinkage rate for the SA hair sample corresponds to 0.27 while it corresponds to 0.24 for the SB hair sample.
[0069] As can be seen, the shrinkage of the hair fibers decreases after application of the cosmetic composition. The shrinkage is slower compared to that of natural hair fibers.
[0070] It is understood that the general description and the detailed description above are both given by way of example and do not restrict the scope of the invention.
Claims
Demands
1. A method for evaluating hair fibers, comprising the following steps: a) performing a first treatment on a first sample of textured hair; and providing a second sample of textured hair; the first treatment comprising the application, on the first sample, of a first cosmetic composition; then b) for each of the first and second samples of textured hair, extending the textured hair (H) to a predetermined length, while measuring an extension force (EF) of the textured hair (H) extended to said predetermined length, then c) for each of the first and second samples of textured hair, stopping the extension so as to allow said textured hair (H) to spontaneously recurl, d) for each of the first and second samples of textured hair, from said stopping the extension,successive measurements over time of a restoring force (RF) during the re-curling of textured hair (H), then e) for each of the first and second samples of textured hair, the generation of a score representative of the shrinkage of textured hair after extension, based at least on said measurements from step d), then f) for each of the first and second samples of textured hair, the generation of information representative of the shrinkage of textured hair after extension based on said score generated in step e), said information corresponding to a shrinkage rate of said textured hair after extension; then g) comparison of said information for the first and second samples, so as to determine which of said samples corresponds to the slowest shrinkage.
2. A method according to claim 1, wherein step a) further comprises carrying out a second treatment on the second sample of textured hair, said second treatment comprising the application, on the second sample, of a second cosmetic composition.
3. Method according to claim 1, step d) being carried out using an extensometer (1).
4. Method according to claim 1 or 2, said extension force (EF) being measured at several different predefined lengths.
5. A method according to any one of the preceding claims, wherein information representative of the score is printed or displayed on an information medium, in particular a leaflet, the packaging of a hair composition, an information or advertising panel, a sales brochure, a television screen or a mobile phone screen.