WO1993006755A1

WO1993006755A1 - Method of lengthening and thickening human hair

Info

Publication number: WO1993006755A1
Application number: PCT/GB1992/001796
Authority: WO
Inventors: David Anthony Gold
Original assignee: David Anthony Gold
Priority date: 1991-10-02
Filing date: 1992-09-30
Publication date: 1993-04-15
Also published as: AU2653292A; GB2260490A; EP0606321A1; GB9120953D0

Abstract

A method of lengthening and thickening human hair comprising applying to the end of a tuft of hair of the desired length, colour and thickness, a molten thermoplastic adhesive so that one end of all of the hairs in the tuft are wetted by the molten adhesive, causing or allowing the adhesive to harden so as to secure all of the hairs of the tuft together, and thereafter heating the adhesive to a molten condition and, whilst in the molten condition, contacting the end of the tuft of hair containing the molten adhesive with hair on the scalp to which the tuft is to be attached and causing or allowing the adhesive to set so that the tuft is secured to the hair on the scalp.

Description

METHOD OF LENGTHENING AND THICKENING HUMAN HAIR

This invention relates to a method of lengthening and thickening human hair.

Various methods are already known for artificially lengthening and/or thickening human hair. For example it is known to attach synthetic hair by various methods to natural hair growing on a human head. This method however has problems, including in particular problems associated with the production of static electricity and the fact that artificial hair neither looks like natural human hair nor behaves like natural human hair. Also, artificial hair fibres tend to fray and also to discolour after a while; will not hold a permanent wave for long; and also causes allergic reactions to some people.

Plaiting or weaving of human hair is also known. However this method is also unsatisfactory, primarily because the method of attachment of the hair tends to loosen and unfasten over a period of time and therefore this cannot be considered to be a satisfactory permanent method.

A method is also known in which hair is bonded to existing growing human hair by a hot melt adhesive. This method involves a technique of taking tufts of human hair of a colour compatible with the hair to which the tuft is to be joined, applying a hot melt adhesive in a molten condition to the tuft of hair, for example by means of a glue gun or brush, and joining the tuft to the existing hair before the adhesive hardens. The adhesive usually comprises a polyester resin, a wax and a pigment. However, there are several significant problems involved in using this technique and the results are seldom satisfactory. Among the difficulties which may be mentioned are the problem of matching the colour of the adhesive to the colour of the hair. The chemical nature of the adhesive is incompatible with human hair which itself releases natural oils which tend to soften the adhesive. The use of hair conditioners also tends to soften the adhesive and the attached hair therefore tends to fall out. The short space of time before the adhesive hardens tends to cause the procedure to be rushed, with a consequence that usually not all of the hairs in the tufts are properly treated with the adhesive and therefore not properly subsequently secured and the hair therefore tends to fall out from this cause also. The necessity of keeping a container of molten adhesive in the salon or treatment room during the procedure is also undesirable due to the resulting unpleasant smell of the molten adhesive. Additionally, the reversal of the hair thickening and extending process, as with all prior art processes, is difficult and usually causes damage to the existing hair.

A problem with most if not all of the above prior methods of thickening and lengthening hair has also been the size and non-uniformity of the knots or oints between the growing hair and the strands or tufts of hair which have been joined to the growing hair. The wearer tends to be conscious of these knots or joints and they may cause serious discomfort to the wearer, for example when lying in bed.

US-A-4 982 748 describes a method of lengthening hair which comprises intertwining or braiding filaments of synthetic hair to sections of natural hair followed by wrapping the braided portion with a portion of synthetic hair, applying a thermosettable material of thermosetting resin and then heating to permanently bond the wrapped portion. It will be seen that this method embodies many of the disadvantages of prior art methods, for example the use of synthetic hair; the production of large knots in the hair of which the wearer is conscious and which are often visible, particularly in fine hair; the permanent adhesive used makes reversal of the process difficult and damage to the hair is inevitable; the process is a complicated one, requiring more than one pair of hands to perform and therefore at least two operatives; and no prior preparation of the hair is carried out which leads to the method tending to be rushed and the results are not uniform.

AU-A-55192/90 describes a tool for joining synthetic hair fibres to natural hair by directly fusing the synthetic hair fibres to natural hair by application of heat. The use of synthetic fibres as hair extensions has the disadvantages already described. Additionally, however in order to give a sufficiently strong bond the strands of human and artificial hair must be wrapped around each other before heat and pressure are applied (otherwise the synthetic hair readily loosens and falls out) thus, in effect, giving knots and lumps. As with all prior art methods which use braiding or knots it is difficult for the wearer to properly clean the hair because grease and dirt become embedded in the interstices of the knots and the grease and dirt are not easily removed by ordinary shampooing. The knots therefore become a potential source of hair and scalp disorders due to lack of proper hygiene. The process of AU-A-55192/90, like other prior art bonding processes is also essentially a one stage process which does not permit adequate preparation to produce uniform results.

US-A-4 934 387 describes a method of attaching supplemental lengths of hair to natural growing hair using coloured thermoplastic glue which involves intertwining warm adhered natural or supplemental hair together. This method also has several of the disadvantages of the prior art methods previously discussed, including the fact that the method is essentially a one stage method without prior preparation of the strands to be attached to the natural hair; the method involves a hot glue gun in close proximity to the human scalp with the obvious attendant dangers; two operators rather than one are needed to perform the method; the number of strands of hair used together with the size of the mass of glue administered by the glue gun and also the lack of effective metering means that significantly sized irregular knots will be produced in the hair with all of the attendant problems as explained hereinbefore. The Applicant has now discovered a new method of lengthening and thickening human hair which avoids the problems inherent in the prior art methods as explained herebefore.

According to the present invention there is provided a method of lengthening and thickening of human hair which method comprises applying to the end of a tuft of hair of the desired length, colour and thickness, a molten thermoplastic adhesive so that one end of all of the hairs in the tuft is wetted by the molten adhesive, causing or allowing the adhesive to harden so as to secure all of the hairs of the tuft together, and thereafter heating the adhesive to a molten condition and, whilst in the molten condition contacting the end of the tuft of hair containing the molten adhesive with hair on the scalp to which the tuft is to be attached and allowing the adhesive to set so that the tuft is secured to the hair on the scalp.

The tuft of hair which is used in the method of the present invention may be a tuft of synthetic or artificial hair. However, it is preferred that human hair is used. Supplies of human hair having a variety of colours, lengths and textures, for example straight or curled, are readily available.

The tuft is typically made up of from about 15 to about 20 individual hairs per tuft, but the number may vary outside this range if desired, for example if a particularly "full" head of hair is sought.

It is a particularly preferred aspect of the present invention that the thermoplastic adhesive used in the method comprises a polyamide or a blend of polyamides having a suitable melting temperature and viscosity.

The use of polyamide thermoplastic adhesives has the particular advantage that the chemical composition of the adhesive is similar to that of human hair which is proteinaceous and contains amide linkages, like those of polyamide resins. The adhesive is therefore less susceptible to the problems inherent in using adhesives which are of a different chemical nature to those of human hair. However, it will be appreciated that the method of the present invention can be used with considerable advantage when using thermoplastic adhesives other than those comprising polyamides, the results being significantly better than those using the prior art methods, although inferior to the results when using adhesives comprising polyamides.

The particular polyamide resins which can be used as, or in, the polyamide adhesives used in the method of this invention may be selected, for example, from nylon 6 (polycaprolacta ) , nylon 6/6 (poly(hexamethy- lene adipamide) ) , nylon 6/10 (the condensation product of sebacic acid and hexamethylene diamine) and nylon 12 (polylaurilactam) . Various polyamides may be blended, as desired, in order to achieve particular desired melting points and/or viscosities. Thus a preferred blend of polyamides used by the Applicant comprises a blend of three polyamides supplied by the firm Chemische Fabrik Tubingen R. Beitlich GmbH & Co. of Tiibigen, Germany, having the trade names "TUBITRANS MELT F", "TRANSLAC MELT 500" and "TUBITRANS MELT". A suitable adhesive composition comprising these polyamide components has approximately 50%, 25% and 25% by weight, respectively of the three components. However, the proportions of, and the selection of, the components may be varied. In the specific combination mentioned above, for example, the first component might be present, for example, in the range of 30 to 70% by weight and the second and third components together might be present in a proportion of 30% to 70% total by weight. The physical properties of the thermoplastic adhesive, in particular the melting point, need to be considered in relation to the method. Thus, the desirable melting point range will generally be between about 80 and about 130 C although it may be outside this range. A sharp melting point is preferred. The viscosity of the melted adhesive must also be such that it will readily adhere to the hair ends of the tuft. It will be appreciated that the melting point of the adhesive should be sufficiently high that the wearer of the extended and thickened hair is able to treat his or her hair as normally as possible, for example shampooing, applying conditioners, and blow drying the hair, without risk of the extended and thickened hair becoming detached due to the thermoplastic adhesive being softened or melted.

The use of a polyamide adhesive also has the advantage that the adhesive is substantially colourless, and therefore tends to be invisible to the eye in a head of hair resulting from the method of the invention, unlike, for example, pigmented polyester resins. The advantage of the method of the present invention in the use of a polyamide-based adhesive that it is virtually invisible once applied and also has a similar chemical nature to hair itself is as if the tuft of extended and thickened hair is joined to the existing hair by a kind of liquid hair.

The two stage method of applying the hair adhesive which the Applicant has discovered enables many of the disadvantages of prior art methods to be overcome. Thus, the tufts of hair to be secured to the head of existing hair can be carefully prepared beforehand so that they are precisely tailored to requirements. Care can be taken to ensure that the lengths of the individual hairs forming the tufts are exactly of the length required or are graded in accordance with requirements. The application of the adhesive can be carried out some considerable time before the second overall step of the method, namely the attachment of the tufts to the human head and can be done, for example, in a separate room to avoid any unpleasant smells resulting from the adhesive being melted in bulk.

The tufts can be gathered and cut at one end so that the ends of all of the hairs comprising the tuft are in line and can be uniformly treated with adhesive, for example by applying a measured dose of a molten adhesive from an extrusion or glue gun. The diameter of the extrusion orifice of the extrusion device may be typically about 1 mm. Desirably the means for dispensing the adhesive on to the end of the tuft of hair should be such that a discrete small globule of adhesive of uniform size is applied to each tuft so that the joints between each tuft and the growing hair are both uniform and small, that is, the minimum amount of adhesive is used whilst ensuring that every strand of hair in the tuft is treated with adhesive. The tuft may thereafter be hung up to permit the adhesive to set. Alternatively, for example, forced cooling may be employed, for example by using a hair blower. Thereafter, the prepared tufts may be arranged so that they are ready for use in attachment to the human head by the method of the invention.

The method used to reheat the adhesive at the end of each tuft in order to secure it to hair on the head is not critical. The heat to be applied needs to be merely that sufficient to melt the adhesive whilst the tuft is joined to the existing hair. Thus, a hot pencil or any other suitable implement may be employed and the adhesive may be allowed to cool in order to set it, or, forced cooling may be employed, for example by means of a hair blow dryer with the heater element switched off.

In view of the fact that in the method of the present invention the ends of all of the hairs making up the tuft of hair to be secured are treated with adhesive the present invention does not suffer from the particular problem associated with the prior art adhesive method, namely the lack of guarantee that all of the hairs are treated with adhesive, with the consequence of subsequent hair fallout. Additionally, since all of the joints between the tufts of extended and thickened hair and the existing hair are small and uniform the wearer will not be so conscious, if at all, of the means by which his or her hair extensions have been achieved, as compared with other known methods, and having gone to great lengths to obtain his or her hair extension and thickening will be very satisfied with the results.

Claims

CLAIMS ;

1. A method of lengthening and thickening human hair which method comprises applying to the end of a tuft of hair of the desired length, colour and thickness, a molten thermoplastic adhesive so that one end of all of the hairs in the tuft are wetted by the molten adhesive, causing or allowing the adhesive to harden so as to secure all of the hairs of the tuft together, and thereafter heating the adhesive to a molten condition and, whilst in the molten condition, contacting the end of the tuft of hair containing the molten adhesive with hair on the scalp to which the tuft is to be attached and causing or allowing the adhesive to set so that the tuft is secured to the hair on the scalp.

2. A method as claimed in claim 1 wherein the thermoplastic adhesive comprises a polyamide or a blend of polyamides.

3. A method as claimed in claim 2 wherein the adhesive composition is substantially transparent and substantially colourless.

4. A method as claimed in any one of the preceding claims wherein a discrete uniform-sized dose of adhesive is applied to each tuft of hair.