Patent Publication Number: US-2011056507-A1

Title: Hair Extension and Method for Hair Extension

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority on Provisional Application No. 61/062,248 filed on Jan. 24, 2008 by the applicant, the disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Hair extension is used for providing decorating effect to a human being&#39;s hair, such as long, curled, straight or different-colored hair. Hair extension requires attaching a number of decorative hair strands to a customer&#39;s natural hair. Decorative hair strands are provided in a form of hair strips and the hair strips are attached to the customer&#39;s hair by gluing. Prior art hair extension strips and methods for attaching the hair strips have disadvantages that long time is required to attach the hair strips since placing and holding the customer&#39;s hair and extension hair together is difficult and; handling the glue is difficult and dangerous; and the bonding between the natural hair and the decorative hair is not uniform. 
     There has long been a need for hair extension strips and method that can provide more natural decorative effect and requires less time consuming and safe attaching process. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a decorative hair strip that provides a natural and firm hair extension. 
     Another object of the invention is to provide a method for attaching the decorative hair strip to a customer&#39;s hair. 
     In order to achieve the objects, the present invention provides a hair extension strip comprising a hollow hair extension strip end piece and a predetermined number of extension hair strands that are embedded in the hair extension strip end piece. 
     The hair extension strip end piece is made of thermoplastic resin. 
     The hair extension strip end piece comprises a hair extension hollow tube having predetermined inner diameter and predetermined length. 
     The predetermined inner diameter is from about 1/16 inch to about ⅜ inch. 
     The predetermined length is from about 1/16 to about ½ inch. The predetermined number of extension hair strands is from about 200 to 450. 
     The hair extension strip that is made by a process comprising steps of aligning ends of a predetermined number of hair strands, applying melted thermoplastic resin around the aligned ends of the hair strands, forming a hollow hair extension strip end piece by wrapping the hair strands around a centering rod and cooling the hair extension strip end piece with the hair strands embedded. 
     The centering rod is circular and has a predetermined diameter, which is from about 1/16 inch to about ⅜ inch. 
     The method further comprises step of removing excess thermoplastic resin so that the amount of thermoplastic resin applied on the ends of the hair strands is from about 0.01 gram to about 0.04 gram. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a hair extension strip according to the present invention. 
         FIG. 2  is a partial enlarged view showing an end piece of the hair extension strip and hair strands embedded in the end piece. 
         FIG. 3  is a schematic view showing the step of aligning hair strands. 
         FIG. 4  is a schematic view showing the step of heating for forming a hair strip end piece. 
         FIG. 5  is a schematic view showing the extension hair strip end piece thus formed. 
         FIG. 6  is a cross-sectional view of the extension hair strip end piece showing hair strands embedded therein. 
         FIG. 7  is a partial elevation view of a centering rod. 
         FIG. 8  is a perspective view of a hair extension tool that is used to attach the hair extension strip to a customer&#39;s hair. 
         FIG. 9  is a schematic view showing a method of attaching the decorative hair extension strip to a customer&#39;s hair. 
         FIG. 10   a  is a schematic elevation view showing step of applying thermoplastic resin. 
         FIG. 10   b  is a perspective view showing step of removing excess resin. 
         FIG. 10   c  is a schematic elevation view showing step of forming a hair strip end piece. 
         FIG. 10   d  is a schematic perspective view showing the hair strip end piece. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a hair extension strip  10  comprising a hollow hair extension strip end piece  12  and a predetermined number of extension hair strands  14  that are embedded in the hair extension strip end piece  12 . 
     The hair extension strip end piece  12  is made of thermoplastic resin or adhesive. 
       FIG. 2  shows that the hair extension strip end piece  12  comprises a hair extension hollow tube  16  having predetermined inner diameter and predetermined length. 
     The predetermined inner diameter is from about 1/16 inch to about: ⅜ inch. The ends of a customer&#39;s hair strands must pass through the hair extension hollow tube  16 , when the hair extension strip  10  is attached to the original, hair of a customer. The predetermined inner diameter is the optimized size for serving this purpose. 
     The predetermined length is from about 1/16 to about ½ inch. The predetermined number of extension hair strands is from about 200 to 450 human hair strands. The lower limit has been determined to increase the efficiency of producing the hair extension strip  10  and labor of attaching the strips  10  to the original hair. The upper limit has been determined considering the adequate number of hair strands that can be embedded in one hair extension strip end piece  12 , and natural look of the extended hair. If the number of the hair strands is more than 450, the hair extension strip becomes too bulky and the thermoplastic resin cannot cover the entire hair strands. 
     The hair extension strip  10  is made by a process comprising steps of aligning ends of a predetermined number of hair strands  14  (refer to  FIG. 3 ); placing a centering rod  18  and a piece of thermoplastic resin  20  having a predetermined weight around the aligned ends of the hair strands (refer to  FIG. 4 ); forming the hollow hair extension strip end piece  12  by heating the resin piece  20  until the hair strands are embedded in the melted resin (refer to  FIG. 5 ); and cooling the hair extension strip end piece  12  with the hair strands  14  embedded. 
     The centering rod  18  is removed after the hair extension strip end piece  12  is formed. Heating of the resin piece  20  may be performed by directly heating the centering rod  18 , or indirectly heating the resin piece  20  and the centering rod  18  by a separate heat source. 
       FIG. 6  shows that the hair strands  14  are embedded uniformly throughout the cross section of the hair extension hollow tube  16 . Molten thermoplastic resin permeates between the hair strands by capillary action during the step of forming the hollow hair extension strip end piece  12 . When the resin solidifies again the uniform distribution of hair strands results. This process is repeated when the hair extension strip  10  is attached to the original hair of a customer. The thermoplastic resin constituting the hair extension strip end piece  12  is melted when heat is applied and permeates between the original hair of the customer and the decorative hair of the hair extension strip  10 . When the resin is solidified again, the original hair and the decorative hair are uniformly fixed in solidified resin, which provides a firm attachment and natural look of the extend hair. 
       FIG. 7  shows that the centering rod  20  is circular and has a predetermined diameter D at its tip  21 . The predetermined diameter D is from about 1/16 inch to about ⅜ inch. The predetermined diameter D becomes the inner diameter of the hair extension strip end piece  12  thus made. 
     The centering rod  20  further includes a stop flange  22  that has a larger diameter than the tip  21 . The stop flange  22  facilitates forming the free end of the hair extension hollow tube  16  (refer to  FIG. 5 ). 
     The predetermined weight of the resin piece is from about 0.01 gram to 0.04 gram. The predetermined amount of the resin has been determined to form adequate size of the hair extension strip end piece  12  for the predetermined number of decorative hair strands  14 . 
     The combination of material, size, and shape of the invention as explained above provides the advantageous effects that production cost of hair extension strips is substantially reduced; time required for completing hair extension is substantially reduced; the hair extension work becomes dramatically easier and precise; and the resulting hair extension is a lot more durable and provides a natural look. 
       FIG. 8  shows a hair extension tool  24  that is used to attach the hair extension strip  10  to the original hair of a customer. The hair extension tool  24  comprises a handle  26  and a hair guide  28  that is supported by the handle  26  and made of an elastic wire. 
       FIG. 9  shows a series of steps that are performed to align the hair extension strip  10  and the original hair with the hair extension tool  24  and to fix them by melting the hair extension strip end piece and re-solidifying the molten thermoplastic resin. Since the ends of the original hair are guided through the hair extension hollow tube with the aid of the hair extension tool, the extension work is greatly simplified and accurate compared to prior art, in which there is no closed curve guide as the hair extension hollow tube of the present invention. The cross-sectional shape of the hair extension hollow tube  16  can be any closed curve including an oval or a rectangle. Multiple number of the hair extension strips  10  can be stacked on the handle of the hair extension tool  24 , which increases the efficiency of hair extension work. 
       FIGS. 10   a - 10   d  show an alternative method for forming the hair extension strip. As shown in  FIG. 10   a , ends of a predetermined number of hair strands  14  are aligned, and melted thermoplastic resin  20  is applied around the aligned ends of the hair strands  14  by dipping the hair strands into a glue pot  40  that contains molten thermoplastic resin  20 .  FIG. 10   b  shows that excess thermoplastic resin  20  is removed by squeezing so that the amount of thermoplastic resin applied on the ends of the hair strands  14  is from about 0.01 gram to about 0.04 gram.  FIGS. 10   c  and  10   d  show that a hollow hair extension strip end piece  12  is formed by wrapping the hair strands  14  around a centering rod  18  and cooling the hair extension strip end piece  12  with the hair strands embedded.  FIG. 10   c  shows the centering rod  18  is inserted into the ends of aligned hair strands  14  so that the ends of the hair strands  14  are wrapped around the centering rod  18 .  FIG. 10   d  shows that the end of the hair extension strip end piece  12  so that the cut end has a flat cross section.