Field of the Invention

The present invention relates to an apparatus and method for the chemical treatment of hair, and in particular to an apparatus for use in a method for the chemical treatment of hair that may include the step of heating hair having a chemical applied thereto.

Background of the Invention

Chemicals are used for treating hair in order to obtain a number of different effects. For example, where coloured highlights (also known as lowlights and weaves) are desired a chemical colourant is applied to individual sections of hair. Usually, the section of hair has a substrate such as a piece of foil or similar placed beneath it prior to the application of the chemical colourant so that the colourant is only applied to the desired section of hair. When the colourant has been applied the foil is folded into a package which contains the section of hair with the colourant thereon.

Different types of substrate are used. For example, aluminium foil continues to be used widely. Other types of foil include a plastic foil described in US5,335,670 and US2007/0089759. Another substrate is a foam having a metallic surface.

A typical highlighting treatment lasts around two hours. One hour is required to apply the colourant to all the sections of hair and arrange correctly the foils and a further period of around an hour is needed for the colourant to react with the hair and change its colour. This means that by the time colourant is being applied to the last sections of hair the first sections of hair will have changed colour.

It would be desirable to speed up the highlighting process.

It has been established that the highlighting process can be shortened by applying heat to hair to which colourant has been applied. Typically, this is done by using a hair straightening iron. It has also been found that by applying heat to hair to which colourant has been applied, different colour effects can be obtained.

However, it has also been found that hair that is heat treated in this way is often damaged. The likely cause of damage is the boiling of the liquid colourant. It would therefore be desirable to provide an apparatus which permits hair to which colourant has been applied to be heated without the colourant rising above a threshold temperature.

Another known use of chemicals in the treatment of hair is in chemical hair straightening. The process of chemically straightening hair is very time consuming, typically taking three to four hours to complete the process on one person.

A typical chemical hair straightening treatment involves:

Washing the hair followed by the application of a chemical straightening cream. The cream is left on the hair for thirty minutes after which it is rinsed from the hair. The hair is blow dried. Following the blow drying step, small sections of hair are passed through a set of hair straightening irons section by section a number of times. Typically each section is passed through the straightening irons five to ten times.

This process is extremely time consuming. Furthermore, the straightening irons, the heating surfaces of which may reach temperatures in excess of 200 degrees C, heat the hair to a temperature that causes the release of significant amounts of steam, dehydrating the hair. This dehydration of the hair is potentially damaging. However, the chemical straightening cream is activated by heat and therefore the heating step is essential to the chemical straightening of hair. Heat can damage the hair cuticle (the outer layer of an individual hair) to such an extent that the cuticle may split along the length of the hair. Also, the ends of individual hairs may split.

It would be desirable to improve the process of chemical straightening of hair.

Summary of the Invention

According to a first aspect of the invention there is provided an apparatus for use in the chemical treatment of hair, the apparatus comprising an elastomer base and a corresponding elastomer cover, each of the base and the cover being flexible, heat resistant to a threshold temperature, having a heat conductivity Q and having a length dimension, a width dimension and a depth dimension, wherein the combination of the depth dimension and the thermal conductivity is such that the temperature of matter situated between the base and the cover does not exceed 100C when subjected to a temperature in the range of 90C to 235C for a period of between 15 and 30 seconds. Preferably, the threshold temperature is at least 100C.

Preferably, the heat conductivity Q is between 0.18 and 0.8 W/m K.

According to a second aspect of the invention there is provided an apparatus for use in the chemical treatment of hair, the apparatus comprising an elastomer base and a corresponding elastomer cover, each of the base and the cover being flexible, and having a length dimension, a width dimension and a depth dimension, wherein the combination of the depth dimension and wherein at least one of the base and cover includes a plurality of spaced apart depressions extending from one end to the other of the at least one base and cover.

According to a third aspect of the invention there is provided an apparatus for use in the chemical treatment of hair, the apparatus comprising an elastomer base and a corresponding elastomer cover, each of the base and the cover being flexible, and having a length dimension, a width dimension and a depth dimension, wherein when the base and the cover are closed a substantially sealed enclosure is formed, thereby substantially preventing leakage of fluid therefrom.

Advantageously, when the base and the cover are closed a substantially sealed enclosure which is adapted to encapsulate hair is formed, thereby substantially preventing leakage of fluid from the apparatus.

Preferably, the temperature of matter situated between the base and the cover does not exceed 80C when subjected to a temperature in the range of 90C to 235C for a period of between 15 and 30 seconds.

At least one of the base and cover may include a plurality of spaced apart depressions extending from one end to the other of the at least one base and cover.

The depressions may have a depth of between 0.1mm and 0.5mm.

The depressions may be spaced apart at centres of 0.1mm and 0.5mm.

The depressions may be curved or straight sided in cross-section.

The apparatus may further include a fastening means.

The fastening means may comprise a two part fastener, one part thereof associated with the base and the other part associated with the cover. The fastening means may include a band that is removably attachable to the base and the cover when the cover is mounted on top of the base.

Preferably, the band is a stretchable continuous band or a two ended band having a band fastener associated therewith.

Advantageously, the elastomer is silicone rubber. The thermal conductivity of elastomer which may be the silicone rubber may be between 0.18 and 0.4 W/m K. It is preferred that the thermal conductivity of the elastomer is between 0.18 and 0.25 W/m -K and preferably, 0.2 W/m -K.

The elastomer may include a filler, such as fibre. The fibre may be glass fibre.

The elastomer includes at least one thermo-chromic pigment, the or each thermo-chromic pigment changing colour at a defined temperature.

The at least one thermo -chromic pigment may change colour at 70 degrees C. The at least one thermo-chromic pigment may change colour at 30 degrees C.

It is preferred that the base is connected to the cover by a hinge.

The base, the cover and the hinge may be formed as one integral piece.

Preferably, the elastomer cover is heat resistant to a temperature up to 235C. Where the heating device is specified to heat to a temperature lower than 235C, the elastomer cover may be resistant to a temperature lower than 235C, for example 190C or 220C. The actual temperature within the range up to 235C to which the elastomer is resistant may be selected according to the temperature to which the apparatus is to be subjected by the heater device.

Advantageously, the depth dimension is between 0.2mm and 1.5mm.

The elastomer may have a Shore A hardness of 60-80.

According to a fourth aspect of the invention there is provided a method of chemically treating hair using the apparatus according to the first aspect of the invention, comprising the steps of: a. washing and/ or combing hair and parting the hair; b. positioning the elastomer base so that one end thereof is adjacent the scalp at the parting; c. placing a section of hair S on to the upper surface of the base and applying a chemical to the section of hair S and/ or applying the chemical to the surface of the base prior to the placement of the section of hair S thereon; d. covering the section of hair positioned on the base by placing the cover directly on top of the base that is beneath the section of hair S; e. fastening together the base and the cover; f. removing the base and the cover from the section of hair S after a period of time required for the chemical to act on the section of hair.

The method may include the further step of applying the chemical to the surface of the second device that contacts the section of hair S.

The chemical may be one of: a hair colourant, a bleaching agent and a straightening chemical.

The chemical is one of: a liquid, a gel and a paste.

The method may comprise the further step of applying heat to the outer surfaces of the base and the cover between steps e and f. The temperature to which the apparatus is heated is dependent on the requirements of the chemical which has been applied to the hair and the hair itself. On the one hand, the chemical needs to be heated to a sufficiently high temperature for said chemical to be activated, but on the other a threshold temperature at which hair may be damaged should not be exceeded, or where the threshold for damage is a combination of temperature and period of exposure to such temperature, that combination should not be exceeded. For hair colourants, heating of the colourant to 20 to 30 degrees C may be sufficient, whereas for hair straightening creams, such as keratin creams, higher temperatures may be necessary, as described herein.

Advantageously, at least one of the base and the cover includes at least one thermo-chromic pigment and the method includes the step of ceasing the application of heat when the pigment changes colour.

Preferably, at least one of the base and the cover has a thermo -chromic pigment and the method includes the step of removing the base and/or the cover when the thermo-chromic pigment changes colour. According to a fifth aspect of the invention there is provided a heating device adapted to apply heat to an apparatus according the first aspect of the invention, the heating device comprising an upper part and a lower part, the upper and lower parts hinged together at one end, and wherein each part mounts a plate and at least one of the plates is associated with a heater.

Each of the upper and lower plates may be provided with a heater.

Preferably, the heater is an electric heater element.

Advantageously, each plate has a length dimension and a width dimension and the length and width dimensions of each plate are fractionally larger than the length and width dimensions of the base and the cover.

Brief Description of the Drawings

In the Drawings, which illustrate preferred embodiments of the invention:

Figure 1 is a plan view of a component of a hair treatment apparatus according to the invention;

Figure 2 is an end view of the component the hair treatment apparatus shown in Figure 1;

Figure 3 is a schematic representation of an apparatus for applying heat to the hair treatment apparatus illustrated in Figures 1 and 2;

Figure 4 is a plan view of the apparatus illustrated in Figure 3;

Figure 5 is a schematic representation of an alternative embodiment of a hair treatment apparatus according to the invention; and

Figures 6 to 9 illustrate the series of steps in the chemical treatment of hair according to a method of the invention.

Detailed Description of the Preferred Embodiments

Referring to Figures 1 and 2, there is shown a device comprising a piece of silicone rubber 1, and tabular in shape in this example, which has sides 2 of length dimension L, and ends 3 of width dimension the piece of silicone having a depth dimension D. In this illustrated embodiment an upper surface 4 includes a series of depressions 5. It is preferred that the depressions 5 have depth of between 0.1mm and 0.5mm and are spaced at centres of between 0.1mm and 0.5mm from one another. The spacing of the depressions need not be related to the depth of the depressions 5. For example, the depressions may have a depth of 0.1mm but be spaced apart at centres of 0.5mm. The depressions may be curved or rectangular in cross-section.

The depressions separate out the strands of hair placed on the surface 4 into many groups of hair, each group comprising a small number of individual hairs. The depressions also form a receptacle for the liquid chemical used. In effect a group of individual hairs in one of the depressions 5 will sit in a bath of liquid chemical which collects in the depression 5.

One of the functions of the silicone is to moderate the transmission of heat from a heating tool, such as a blow dryer, a hair straightening iron, a heating device as described herein or other suitable heating apparatus, to hair encapsulated between surfaces of the device.

Where a hair straightening iron is used as the heating device, the working temperature of the straightening iron may be between 75 and 235C with the straightening iron typically having a power requirement of between 20 watts and 160 watts.

Where a hair dryer is used, the air temperature will typically be around 90C or 120C. However, hair dryers with other temperature settings may also be used. The typical power requirement of a heated air dryer would be around 2000 watts.

The depth D is typically in the range 0.2mm to 1.5mm.

The silicone rubber may have at least one thermo -chromic pigment therein. The thermo- chromic pigment selected will depend on the temperature that a particular chemical needs to reach, which in turn determines the temperature to which the elastomer is raised. It has been found that if the temperature of the elastomer does not exceed 90C then liquid encapsulated between the two of the devices does not boil. A thermo-chromic pigment is therefore selected that changes colour at 70C. It is possible that a number of thermo -chromic pigments, or a pigment that starts to change colour at a first temperature such as 30C and completes its colour change at a second temperature such as 70C may be included so that the device 1 changes colour a number of times as it is heated. Such a colour change may be desirable simply to provide information to the user about the progress of heating, or to indicate that another threshold has been passed. For example, after a period of heating of the device ends, it may be desirable to know when a certain cooling point has been reached, since this may indicate that another step in the process may be undertaken.

Figures 3 and 4 illustrate a heating tool 10 adapted for use in applying heat to hair contained in the device of the invention. The tool 10 comprises a bottom part 11 mounting a plate I la and a top part 12 mounting a top plate 12a hinged, the two parts 11, 12 together at a hinge 13. At least one of the bottom and top plates I la, 12a includes an electrically powered heating element (not shown), receiving electrical power from an electrical power source, which in this example is cable 14.

The top and bottom plates Ila, 12a each have a length L’ and a width W’. The length L’ is fractionally longer than the length T of the device 1 and the width W’ fractionally wider than the width W of the said device 1. By so specifying the length L’ and widths W’ of the plates 11, 12 relative to the respective length L and width W of a device 1, even heating of the device 1 and hair encapsulated therein can be ensured.

Figure 5 illustrates an alternative embodiment of the piece of silicone rubber. In this embodiment in essence two pieces 1, T are connected by a region of silicone of reduced thickness 6, which forms a hinge. The piece of silicone rubber 1 is shown with depressions 5 in its upper surface 4 and the piece T without. However, either one, neither or both of the pieces of silicone rubber 1, T may be provided with depressions 5.

The device 1 may be used for the chemical treatment of hair in many different ways. Some examples described with reference to Figures 6 to 9 are set out below:

Example 1 - Highlighting Hair Without Heat Treatment

1. In Figure 6 the hair has been prepared for the application of a colourant, by washing and/ or combing and parting at P;

2. In Figure 7 the device 1 is positioned so that one end 3 of the device 1 is adjacent the scalp at the parting P;

3. In Figure 8 a section of hair S is placed on to the upper surface 4 of the device 1 and a colourant is applied to the section of hair S; Instead of or as well as applying colourant to the hair, the colourant may be applied to the surface of the device 1 prior to the placement of the section of hair S thereon;

4. In Figure 9, the section of hair S is covered by placing a second device 1’ directly on top of the device that is beneath the section of hair S;

The surface of the second device that contacts the section of hair S may have colourant applied thereto;

5. If the device 1 is not provided with any interlocking means, a fastener such as a stretchable band is wrapped around the two devices 1, T;

6. The section of hair S remains encapsulated for the time required to obtain the colour effect provided by the colourant used; and

7. The devices are removed.

Example 2 - Highlighting Hair With Heat Treatment

As described above, it is known that heating hair to which a colourant has been applied can speed up the colouring process (by reducing the amount of time the colourant needs to be left in place) and/ or give different colouring effects from the same chemical colourant.

Heat may therefore be applied between steps 6 and 7 above using any suitable heating apparatus, which may be an apparatus as shown in Figures 3 and 4 or a hair drier of the types known in the art. The temperature to which the device and hence hair and chemical is heated and the duration of such heating is specific to the chemical used and desired effect, subject to damage to the hair being prevented.

Example 3 - Chemical Straightening of Hair with Heat Treatment

1. In Figure 5 the hair has been prepared for the application of a straightening chemical, by washing and/ or combing and parting at P;

2. In Figure 6 the device 1 is positioned so that one end 3 of the device 1 is adjacent the scalp at the parting P; 3. In Figure 7 a section of hair S is placed on to the upper surface 4 of the device 1 and a straightening chemical is applied to the section of hair S;

Instead of or as well as applying straightening chemical to the hair, the straightening chemical may be applied to the surface of the device 1 prior to the placement of the section of hair S thereon;

4. In Figure 8, the section of hair S is covered by placing a second device 1, 1’ directly on top of the device that is beneath the section of hair S;

The surface of the second device that contacts the section of hair S may have straightening chemical applied thereto;

5. If the device 1 is not provided with any interlocking means, a fastener such as a stretchable band is wrapped around the two devices 1, T;

6. The encapsulated section of hair S is heated to a temperature and for a period of time required to activate the straightening chemical using either a heating apparatus 10 or another suitable heating apparatus;

7. The heating apparatus is removed and the devices 1, T are removed;

8. The straightening chemical is rinsed off; and

9. The hair is dried, with or without the used of a dryer.

The chemical straightening process of the invention differs significantly from the known process. First, heat is applied before any straightening chemical has been rinsed off. Second, the repeated passage of hair through straightening irons, where the hair is in direct contact with heated irons, is avoided. The hair is heated once to a controlled temperature that is sufficient to activate the straightening chemical but which mitigates against damage to the hair. The result is a significantly faster process. The straightening effect is better because the hair is surrounded completely by straightening chemical between the devices 1, T. The hair suffers less damage since it is heated to a lower temperature. The hair may be subjected to heat for a shorter period. Where a thermo-chromic pigment is used an indication is given that the desired temperature has been reached and the heat source may be removed. The devices 1, T may be cleaned and reused, whereas the foils of the prior art are typically disposed of after a single use. Also, the time taken to position the devices 1, T is significantly less than traditional foils that require folding.