EP0041446B1 - Method of hair-forming - Google Patents

Abstract

A method and device for setting hair relies on the use of a hair setting process in which, after partial drying but before unrolling of the hair from curlers or rollers on which it is wound after moist treatment, the hair is subjected to a conditioning step in an atmosphere having a relative humidity of from 36 to 80% at a temperature of from 35 DEG to 75 DEG C. and for a period of from 5 to 60 minutes.

Description

The present invention relates to a new method for shaping the hair. The method according to the invention finds its application either in the making of styling, or for the straightening of a hair, or a wig of natural hair, which is considered to be naturally too curly.

The method according to the invention consists in giving the hair a non-definitive shape, that is to say a temporary shape, which disappears when the hair is again wet, in particular when it is subjected to a shampoo; the difference, which exists between the temporary deformation conferred by the process according to the invention and a permanent deformation, which implies a chemical treatment, thus resides in the fact that the hair having undergone the process of deformation according to the invention finds, when they are wet, the shape they had before the application of the process whereas after a permanent deformation, the shape of the hair is not altered by wetting or by washing.

For convenience of language, we will speak, in the remainder of this description, of the styling process, it being understood that this term must be considered to include straightening without chemical treatment; similarly, we will speak of hair, it being understood that this term must be considered to include natural hair wigs.

The most commonly used method of styling hair consists of wet hair which is rolled up on supports called "curlers" or "styling rollers", then drying the hair under a helmet at a temperature included between 30 and 60 ° C for a time which can vary from 20 to 60 minutes depending on the mass of the hair to be dried, then unroll the curlers and give the hairstyle a comb. In a variant, the initial wet treatment is carried out using a styling lotion which can be constituted, for example, by a solution of reinforcing agents such as resins which, after drying, sheath the hair and keep them in their position.

It has been found that the hair subjected to such a styling process has a behavior which changes as a function of time after the end of drying. Firstly, it has been found that the wet treatment, to which a hair is subjected during wetting with water or a shampoo, causes an increase in the weight of the hair. The relative change in weight is around 35%. The drying of the hair in a circulation of hot air causes a loss of water, which is greater than the weight gain of the hair during the wet treatment and, at the end of drying, the relative variation of the weight of the hair compared to the weight before wet treatment is generally close to -9%: this weight loss is, of course, essentially a function of the drying and, in particular, of its duration and of the temperature of the forced air used. When the drying is finished, it is noted that the hair gradually regains moisture in the ambient air and this behavior of the hair has been shown in FIG. 1 of the attached drawing; generally, the hair returns to the weight it had originally before the wet treatment takes several hours.

When a styling has been carried out by the method of the state of the art previously indicated, the hair is unrolled from the curlers just after drying and, at this time, they have a crimp close to that which one could consider ideal for curlers used. To identify the crimp, it is possible, on an experimental basis, to achieve styling on the lock and at the time when the hair is rolled out, if the lock is suspended, it can be noted how long the lock is. If we then leave the wick thus suspended and therefore subjected to the action of its own weight, in contact with the external atmosphere, we see that the length of the wick increases over time, this phenomenon taking place at the same time as the water recovery, which was previously discussed. As a result, the effectiveness of styling gradually disappears over time, which is, of course, a significant drawback. However, it has been found that this phenomenon is very strongly influenced by the moment when, after the end of drying, the hair is unrolled by removing the curler; it has been found, in fact, that if the hair is left in place on the curler for a certain time after the end of drying, the lengthening of the locks is considerably reduced over time. In Figure 2, the curves explaining this phenomenon are shown; on these curves, the time expressed in hours is plotted on the abscissa, the length of a suspended wick expressed in millimeters is plotted on the ordinate and the duration d expressed in hours is parameterized as a curve, d representing the time between the end of the drying and unwinding the wicks. We see that, just at the end of drying, all the locks have loops having substantially the same length L _o and we have shown in phantom the curve, which would correspond to an ideal holding of the setting, that is ie a maintenance over time of the shape acquired by the hair.

It can be seen by studying the curves in FIG. 2 that, to obtain a satisfactory result, it would be desirable to maintain the curlers for a very long time after the end of the drying. Now, the recovery of water from the hair after the end of drying takes place relatively quickly, as shown in FIG. 1. It is therefore observed that it occurs in the hair, a phenomenon subsequent to the end of recovery of water, said phenomenon having a very great influence on the holding of styling over time. It is believed, without this explanation being in any way limiting, that said phenomenon is a rearrangement of the constituent molecules of the hair; if this rearrangement occurs, while the hair is still coiled on the curlers, the holding of the styling is much greater than it is, when the rearrangement occurs when the hair has already been unwound.

By way of purely explanatory hypothesis and without this in any way constituting a limitation of the invention, it is believed that the wet treatment of the hair allows the penetration of water into the hair and increases the dielectric constant of the medium existing between the charged sites of the constituent molecules of the hair, so that the hydrogen bonds no longer exist for wet hair.

When the drying is carried out, the water molecules are extracted from the hair in an amount such that there is a loss in weight relative to the initial weight; the charged sites of the constituent molecules of the hair which had been discarded due to the presence of the water molecules, remain relatively spaced apart and do not allow instantaneously at room temperature, the reformation of the hydrogen bonds, this reformation only taking place gradually with relatively low speed. The water molecules, which return to the hair at room temperature to ensure the recovery of water after the end of drying, are in the form of agglomerates the larger the lower the temperature and the rearrangement of these molecules. of water in the hair takes place slowly. It can therefore be seen that the rearrangement of the distribution of water in the hair, on the one hand, and the reformation of the hydrogen bonds in the hair, on the other hand, are phenomena which, at ambient temperature, occur so slow and which, presumably, constitute what was previously called the rearrangement of the hair.

According to the present invention, it was thought that one could increase the speed of rearrangement of the hair by increasing the temperature at which this rearrangement takes place. However, it was also found, according to the invention, that it was appropriate during this rearrangement to ensure the uptake of water from the hair to bring it back to a state where it is approximately in hygrometric equilibrium with the external atmosphere at room temperature . We have therefore imagined, according to the invention, to follow the drying of the hair by a conditioning phase, during which a relatively high relative humidity is maintained to allow water to be taken up from the hair, water taking up which is necessary, since at the end of drying, the hair always has a weight loss compared to the initial weight before wet treatment. To obtain a rapid rearrangement after drying, it has been found that it is necessary to place the hair in an atmosphere having a temperature between 35 ° C. and approximately 75 ° C. and having a relative humidity of between 40 and 80% approximately.

It was further noted, surprisingly, that it was necessary for the drying to be pushed to a point where the hair exhibits a loss of water compared to its initial condition and that the conditioning phase must necessarily ensure a recovery of water from the hair; in fact, if the drying is stopped when the hair has returned exactly to its initial weight before wetting, it can be seen that the rearrangement of the conditioning phase, which the invention recommends, occurs only incompletely.

All other things being equal, it was found that the performance of a styling according to the invention was a function of the relative humidity during the conditioning phase, said function having a maximum for the relative humidity which corresponds to the relative humidity of the external atmosphere in contact with which the hair is found after the end of the conditioning phase. In addition, it has been found that, all other things being equal, the performance of the styling increases when the temperature during the conditioning phase increases. These two phenomena are translated by the curves of Figures 3 and 4; in FIG. 3, the yield is plotted on the ordinate, the relative humidity expressed in% is plotted on the abscissa, the drying and conditioning times and temperatures constitute parameters of given value; in FIG. 4, the yield expressed in% is plotted on the ordinate, the conditioning temperature expressed in ° C is plotted on the abscissa, the drying time and temperature as well as the conditioning time and the relative humidity during the conditioning constitute parameters of given value. In FIG. 4, the hatched part of the plane corresponds to the area which it is not possible to reach since the users of the process could not withstand temperatures of this order. For the two curves of FIGS. 3 and 4, the yield is expressed as a percentage improvement compared to the lengths of the control locks, which have undergone conventional styling, with drying at 60 ° C. for a total equal time. at the complete treatment time of the process according to the invention, immediately followed by an unwinding of the locks in a standard atmosphere (for example at 26 ° C. and 56% relative humidity).

It should be noted that the method according to the invention is quite different from the hair treatment methods which hitherto envisaged treating the hair with steam. Indeed, it is known, in particular from French patent 2,305,148, that a styling technique of known type consists in subjecting dry hair to a mixture of air and water vapor at a level which is bearable for the scalp, this mixture being propelled towards the hair using a blower helmet or a hand dryer. In this case, the suction of the drying and conditioning phases, which it has been found according to the invention, is not found to be necessary in order to show a good styling yield and good resistance over time. In French patent 2,273,492, it has also already been proposed to subject the hair to the action of water vapor. superheated for a period of about 1 to 60 seconds; in this process, on the one hand, the action of the superheated water vapor takes place in too short a time for the restructuring of the hair after drying to take place and, on the other hand, the atmosphere around the hair is at a relative humidity of 100% during the steam treatment, which is very different from a limited relative humidity such as that which is recommended in the conditioning phase of the process according to the invention. It has been found, in fact, that if the conditioning phase of the process according to the invention was carried out with a relative humidity of 100%, the yield of the styling tended towards zero. Thus, a treatment of the type recommended in Swiss patent 349 373 may be of interest in the field of hair dyeing but produces zero result with regard to the styling effect.

The present invention therefore has as an object a method for carrying out hair shaping, in which the hair is subjected to a wet treatment, the hair is rolled up on bodies of suitable shapes serving as curlers, drying of the coiled hair until it has a loss of water compared to its initial state before the wet treatment and the hair is unwound after drying, characterized in that before the hair is unwound, but after the having dried, said hair is subjected to a conditioning phase known per se, the duration of which is between 5 min and 60 min approximately, said conditioning phase being carried out in an atmosphere having a relative humidity of between 35 and 80% approximately, at a temperature between about 35 ° C and 75 ° C.

When this method is applied, there is an improvement in the holding performance of the styling. The hair is soft, shiny, easy to comb and not electric; the hair has more volume. In a preferred embodiment of the method according to the invention, the relative humidity of the conditioning phase is fixed at a value close to the relative humidity of the ambient atmosphere with which the hair will be in contact, when they will take place; the temperature is maintained during the conditioning phase at a value between 45 and 60 ° C and, preferably, close to 50 ° C; maintaining the temperature of the atmosphere, where the hair is located during the conditioning phase, at a value close to the temperature during the hair drying phase; during the conditioning phase, moisture is taken up in the hair which, as a percentage relative to the weight of the hair before the wet treatment, does not differ from the weight loss on drying, expressed as a percentage relative to the weight of the hair before the wet treatment, only less than 2%; the conditioning phase is maintained for a time of between 10 and 20 minutes approximately; the conditioning phase is carried out by injecting water vapor into the atmosphere, where the hair is located; during the conditioning phase, a treatment product is injected into the atmosphere, where the hair is located.

The term "treatment product" means a product ordinarily used in cosmetics, such as anti-seborrheic, anti-dandruff, anti-hair loss agents, film-forming resins, deodorants, disinfectants, perfumes, brilliantine and analogues.

Advantageously, the hair is dried until it reaches a relative humidity of around 15% in the atmosphere which surrounds the hair; the hair is dried until a weight loss is obtained, relative to the weight of the hair before the wet treatment, of between 1 and 15% and preferably between 5% and 15%; the hair is dried at a temperature between 40 and 75 ° C for a time between 10 and 60 minutes; hair is dried by ventilation of air taken outside and heated, in open circuit.

Provision may be made for the initial wet treatment of the hair to be a wetting with water and / or a shampoo and / or a cosmetic treatment involving wetting of the hair with an aqueous or hydro-alcoholic solution, for example a solution of reinforcement such as resins; after unrolling the hair, a non-wetting cosmetic treatment can be applied to them, such as a spray of hairspray.

In the case where the method is intended to obtain styling of the hair, the bodies used for winding the hair are curlers or styling rollers; in the case where the method is intended to obtain a hair straightening, the bodies used for winding the hair are rollers of large diameter. The hair treated by the method according to the invention can be natural hair, bleached, colored or permed.

To better understand the object of the invention, we will now describe, by way of purely illustrative and non-limiting, several modes of implementation. The appended drawing provides the explanatory curves relating to the process according to the invention and schematic representations of the implementation of the process.

• - la figure 1 représente la courbe donnant en fonction du temps la variation relative de poids en % d'un cheveu mouillé soumis à un séchage à 60°C pendant 45 minutes puis abandonné dans une atmosphère à 26° C et 56% d'humidité relative;
• - la figure 2 représente un réseau de courbes montrant la variation de longueur d'un cheveu soumis à un procédé de mise en plis de type classique, le paramètre du réseau de courbe étant le délai entre la fin du séchage et le déroulement des cheveux;
• - la figure 3 représente la variation du rendement du procédé selon l'invention en fonction de l'hygrométrie relative pendant la phase de conditionnement;
• - la figure 4 représente la variation du rendement du procédé selon l'invention en fonction de la température pendant la phase de conditionnement;
• - la figure 5 représente schématiquement un premier mode de mise en ceuvre du procédé selon l'invention;
• - la figure 6 représente schématiquement un deuxième mode de mise en oeuvre du procédé selon l'invention;
• - la figure 7 représente schématiquement une variante du deuxième mode de mise en oeuvre du procédé selon l'invention.

On this drawing:

• - Figure 1 shows the curve giving as a function of time the relative weight change in% of a wet hair subjected to drying at 60 ° C for 45 minutes and then left in an atmosphere at 26 ° C and 56% humidity relative;
• - Figure 2 shows a network of curves showing the variation in length of a hair subjected to a styling process of conventional type, the parameter of the network of curves being the time between the end of drying and the unwinding of the hair;
• FIG. 3 represents the variation in the yield of the method according to the invention as a function of relative humidity during the conditioning phase;
• - Figure 4 shows the variation of the yield of the process according to the invention as a function of the temperature during the conditioning phase;
• - Figure 5 shows schematically a first mode of implementation of the method according to the invention;
• - Figure 6 schematically shows a second embodiment of the method according to the invention;
• - Figure 7 shows schematically a variant of the second embodiment of the method according to the invention.

As already indicated at the beginning of this description, FIG. 1 shows that a hair undergoes an increase in weight of 35% at the time of its wetting and then returns by drying in 45 min at 60 ° C to a lower weight. 9% of its initial weight. The hair left in an atmosphere at 26 ° C and 56% relative humidity roughly returns to its initial weight about 2 hours after the end of drying.

As was also indicated at the beginning of this description, FIG. 2 gives the variation of the length L of a lock of hair, expressed in millimeters, as a function of the time t expressed in hours when the lock, having undergone a process conventional styling, is unwound from his curler at a time Δ counted in hours from the end of drying. We see that the effectiveness of styling decreases very quickly if we do not maintain the hair on curlers for a relatively long time after the end of drying. However, it is quite clear that such a constraint is not bearable for users of styling and it follows that conventional styling has an effectiveness of very short duration.

Was carried out, on an experimental basis, on locks of natural and bleached hair, styling using the method according to the invention.

Tables 1 and II give the experimental results for a process, which comprises drying for 45 minutes at 60 ° C. using a ventilated helmet-dryer followed by a conditioning phase, the characteristics of which are given in the first column. Tables I and II; the relative humidity is designated by RH during the conditioning phase and by 0 _c the temperature of the atmosphere that surrounds the hair during the conditioning phase. The duration of conditioning expressed in minutes is indicated in the second column of these two tables. In the third column of these tables, the lengths of the locks subjected to the shaping process of the invention have been shown after a period of 5 hours counted from the time when they are unrolled from their curler-support. By way of comparison, a control wick is used, which has undergone the drying operation under the conditions indicated above but which has not undergone any conditioning phase, the wicks being unwound just after drying. The ratio of the length of a lock treated with the method according to the invention to the length of the control lock (the two measurements being made five hours after the unwinding of the locks) gives in% the improvement that the method according to the invention; this improvement is indicated in the fourth column of Tables 1 and II. Finally, the fifth column of the two tables gives the water uptake of the treated locks, five hours after the end of the treatment.

It is clear, from the results of Tables 1 and II, that in the whole range of relative humidity explored both for natural hair and for bleached hair, the method according to the invention makes it possible to obtain a percentage of very significant improvement. It should be noted that the relative humidity of 56% at which some of the experiments were carried out corresponds to the relative humidity of the external atmosphere with which the wicks are brought into contact after the end of the treatment. It can be seen that for a relative humidity of 56%, and for natural hair, the effectiveness of the conditioning phase is already very satisfactory after 15 minutes of conditioning. This observation is extremely interesting because the users of the method generally bear quite poorly an increase in the total time of the treatment intended to achieve styling. The usual treatment involves drying for 45 minutes and it is therefore desirable to be able to bring the time for implementing the method according to the invention to around this value of 45 minutes. However, it was found that, if drying was carried out for 30 minutes followed by conditioning at 50 ° C. and 56% relative humidity, the results were clearly better than if drying was continued for 45 minutes at same temperature of 60 ° C. It is therefore quite possible to carry out drying for 30 minutes at 60 ° C followed by a conditioning phase of 15 minutes at 56% relative humidity and 50 ° C, which allows achieve a 28% improvement without increasing the processing time compared to a conventional styling process. It is very clear that the multiplicity of the parameters present makes it possible to seek an optimum taking into account the particular cases.

The results obtained on natural hair were recorded in table III by varying the drying time on the one hand at 60 ° C. and, on the other hand, the conditioning conditions (HR and HR _c have the same meanings as in Tables I and II). In this table III, the percentage improvement and the percentage of water uptake were calculated, as indicated for tables I and II.

FIG. 3 schematically translates on a curve the experimental results recorded in Tables I, II and III. This curve shows the variation in the yield of the process according to the invention (scope on the ordinate) as a function of the relative humidity during the conditioning phase, the yield being identified by the improvement in% as calculated in the penultimate column of Tables I, II and III; this graph shows, without any precision, the shape of the curve and assumes constant the other parameters, namely, the drying temperature (60 ° C), the drying time (30 minutes), the conditioning temperature (50 ° C ) and the conditioning time (15 minutes).

Similarly, FIG. 4 schematically shows the shape of the curve for variation of the yield of the process according to the invention as a function of the conditioning temperature which is adopted; the yield indicated on the ordinate is calculated in the same way as for the ordinate of FIG. 3; the conditioning temperature is indicated on the abscissa and expressed in ° C. The other parameters are kept constant, namely the drying time (30 minutes), the drying temperature (60 ° C), the conditioning time (15 minutes) and the relative humidity of the packaging (56%).

The implementation of the method according to the invention can be carried out according to several different modes.

The first implementation made is shown diagrammatically in FIG. 5. A helmet-dryer of the conventional type 1 is used intended to carry out the drying phase of the styling process according to the invention and an enclosure-oven 2, distinct of the helmet-dryer 1, said enclosure-oven being supplied by line 3 so that a constant relative humidity is maintained there. The temperature inside the oven enclosure 2 is also kept constant. The user, who has had their hair wetted either with water or by shampooing and rinsing, optionally with the application of a polymerizable reinforcing agent, rolls up or has their strands of hair rolled up on curlers and is placed under the helmet -drier 1 during the drying time. At the end of this drying time, the user places her hair in the oven 2 enclosure and maintains it there for the expected conditioning time. Then, the user removes her curlers by unrolling the hair and performs a finishing combing.

The second embodiment is shown diagrammatically in FIG. 6. In this figure, it can be seen that the user, whose hair has been wet and wound on curlers as indicated above, places her hair inside a flexible cap 4, made for example of plastic, said cap being connected by a pipe 5 to a heating member and / or humidifier 6. During the drying phase, the member 6 sends hot air into the cap 4 and the air is evacuated via line 5 which serves both to bring it in and to evacuate said air; the drying air is exhausted to the outside. When the drying phase is completed and the conditioning phase begins, the air circulation provided by the member 6 is no longer in an open circuit, but in a closed circuit and the member 6 adds to the circulation air a sufficient amount of water to maintain inside the cap 4 a constant relative humidity. Instead of water, it is possible to introduce into the air during the conditioning phase an aqueous or hydroalcoholic liquid for treating the hair or the scalp.

In another embodiment shown in FIG. 7, a dryer hood 7 of the conventional type modified is used to allow this implementation. The dryer hood 7 is equipped with a fan 8 which sucks in the outside air according to the arrow F and pulses it after heating in the direction of the hair, the forced air emerging from the helmet around the head of the user according to the arrows F1. The helmet 7 is equipped with a device 9 allowing injection into the pulsed hot air flow of a quantity of steam intended to maintain a constant relative humidity. After the user's wet hair has been rolled up on curlers, the hair is put under the helmet 7 and the drying phase of the process is started. When the drying time has elapsed, water vapor (a treatment liquid in the vapor state) is introduced through line 9 throughout the duration of the conditioning phase, the quantity of steam being regulated so as to maintain a constant relative humidity around the hair.

It is understood that the modes of implementation described above are in no way limiting.

Claims (17)

1. Process for shaping hair, in which the hair is subjected to a wet treatment, the hair is wound on bodies of appropriate shapes serving as curlers, the hair thus wound up is dried until it exhibits a loss of water relative to the initial condition of the hair before the wet treatment, and the hair is unwound after drying, characterised in that before unwinding the hair but after having dried it the said hair is subjected to a conditioning stage which is known per se and the duration of which is approximately between 5 minutes and 60 minutes, the said conditioning stage being carried out in an atmosphere having a relative humidity approximately between 35 and 80% at a temperature approximately between 35° C and 75° C.

2. Process according to Claim 1, characterised in that the relative humidity chosen during the conditioning stage is close to the relative humidity of the ambient atmosphere to which the hair is exposed after the application of the shaping process.

3. Process according to Claim 2, characterised in that the conditioning stage is carried out at a temperature of between 45 and 60° C and preferably of about 50° C.

4. Process according to one of Claims 1 to 3, characterised in that the conditioning stage is carried out at a temperature close to that prevailing during the stage of drying the hair.

5. Process according to one of Claims 1 to 4, characterised in that during the conditioning stage a reabsorption of moisture by the hair is ensured, which reabsorption, in per cent relative to the weight of the hair before the wet treatment, only differs by less than 2% from the loss in weight on drying, expressed in per cent relative to the weight of the hair before the wet treatment.

6. Process according to one of Claims 3 or 4, characterised in that the conditioning stage is carried out for a period of approximately between 10 and 20 minutes.

7. Process according to one of Claims 1 to 6, characterised in that the conditioning stage is carried out by injecting steam into the atmosphere to which the hair is exposed.

8. Process according to one of Claims 1 to 7, characterised in that during the conditioning stage a treatment product is injected into the atmosphere to which the hair is exposed.

9. Process according to one of Claims 1 to 8, characterised in that the drying of the hair is continued until the relative humidity in the atmosphere surrounding the hair is about 15%.

10. Process according to one of Claims 1 to 9, characterised in that the drying of the hair is continued until a loss of weight of between 1 and 15%, relative to the weight of the hair before the wet treatment, is reached.

11. Process according to one of Claims 1 to 10, characterised in that the drying of the hair is carried out at a temperature of between 40 and 70° Cfor a period of between 10 and 60 minutes.

12. Process according to one of Claims 1 to 11, characterised in that the drying of the hair is effected by open-circuit blowing of air which has been taken from the outside and been heated.

13. Process according to one of Claims 1 to 12, characterised in that the initial wet treatment of the hair is effected by wetting the hair and/or by shampooing and/or by a cosmetic treatment involving the wetting of the hair with an aqueous or aqueous-alcoholic solution.

14. Process according to one of Claims 1 to 13, characterised in that after unwinding the hair a non-wetting cosmetic treatment such as a lacquer spray is applied to the hair.

15. Process according to one of Claims 1 to 14, intended to produce a hair waveset, characterised in that the bodies used for winding up the hair are curlers or wavesetting rollers.

16. Process according to one of Claims 1 to 14, intended to achieve a straightening of the hair, characterised in that the bodies used for winding up the hair are rollers of large diameter.

17. Process according to one of Claims 1 to 16, characterised in that natural, bleached, dyed or permanent-waved hair is treated.

Images