Field of the Invention

The present invention generally relates to hair extensions, and more specifically to synthetic hair extensions and methods for making the same.

Background of the Invention

In general, hair extensions are additional hair that is used to add volume, length, and depth to a natural hairline. Braiding, bonding and weaving, and hair extension clip-ins are some popular hair extension methods. Depending on the wearer's requirements, budget, and hair type and length, hair extensions are typically chosen after consulting a hair expert. Hair extensions are safe and trusted by women all over the world for solving issues related to thinning hair, hair loss, and even balding. Women of any age can use hair extensions.

In the past, there were only human hair extensions made of real human hair. These human hair extensions are expensive and their availability is limited. As a result, the use of human hair extensions was limited to the wealthy and famous. Now there has been developed another type of hair extension— synthetic hair extensions that are manufactured artificially.

With the advent of synthetic hair extensions, the cost has decreased and the availability has increased. As a result, hair extensions are now commonly worn by people from every walk of life and of every nationality and race.

Human and synthetic hair extensions each have advantages and disadvantages, and can be differentiated on such factors as price, longevity, styling, maintenance, and feel. For example, human hair extensions look natural and real, can be colored and styled without restrictions, and are long lasting. However, human hair extensions are more expensive than synthetic extensions, require constant care and attention like real human hair, and can be sourced in an unhygienic manner. Synthetic hair extensions advantageously do not require treatments like deep conditioning, are less expensive than human extensions, and have the ability to add more volume. But conventional synthetic hair extensions typically are distinguishable from human hair, have an unnatural feel, break easily, and are difficult to incorporate and style.

In view of the foregoing, improved synthetic hair extensions are needed. In particular, what is needed are synthetic hair extensions that feel and look like human hair, that are stronger, and that are soft and smooth to the touch, along with methods for making the same.

Summary of the Invention

One embodiment of the present invention provides a mixture for extrusion into polypropylene yarn. The mixture comprises polypropylene resin, 2-8% magnesium stearate, and 3-8%) dye (percentages by weight relative to weight of polypropylene resin). The mixture optionally also comprises l-4%> flame retardant.

Another embodiment of the present invention provides a method for making synthetic hair extensions. According to the method, raw material including polypropylene resin is mixed, the raw material is extruded to produce polypropylene yarn, some of the

polypropylene yarn is formed into a hank, the ends of the yarn are pressed between the sheets of a press such that the ends abut a lip of one of the sheets, and the hank of yarn with the press is passed through a conveyor furnace to relax the yarn.

Other objects, features, and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only and various modifications may naturally be performed without deviating from the present invention.

Brief Description of the Drawings

Figure 1 is a flowchart showing a process for making synthetic hair extensions according to one embodiment of the present invention;

Figure 2 shows an exemplary melt spinning process;

Figure 3 shows a polypropylene yarn production machine that is used in one embodiment of the present invention;

Figures 4A and 4B show a press that is used in one embodiment of the present invention;

Figure 5 shows a drum tumbler that is used in one embodiment of the present invention;

Figure 6 shows a side view of an upper portion of the polypropylene yarn production machine;

Figure 7 shows a perspective view of the polypropylene yarn production machine; Figure 8 shows spinnerets of the polypropylene yarn production machine; Figure 9 shows winder heads of the polypropylene yarn production machine;

Figure 10 shows the oil dispenser of the polypropylene yarn production machine; Figures 11 and 12 show the use of a skein winder in one embodiment of the present invention;

Figures 13-15 show the use of the press in one embodiment of the present invention; Figure 16 shows a fiber relaxation tunnel that is used in one embodiment of the present invention;

Figures 17 and 18 show hanks that have passed through the fiber relaxation tunnel; Figures 19 and 20 show hanks after rest periods;

Figures 21 and 22 show hanks after being brushed; and

Figure 23 shows synthetic hair extensions produced according to a process for making synthetic hair extensions according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

As required, embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely examples and that the systems and methods described below can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present subject matter in virtually any appropriately detailed structure and function. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the concepts.

Embodiments of the present invention provide improved synthetic hair extensions and methods for making the same. The improved synthetic hair extensions look and feel like human hair, and blend seamlessly with human hair. They are strong but soft and smooth to the touch. The improved synthetic hair extensions also provide many benefits to hair stylists such as saving time, lowering waste, and increasing revenues because they are tangle free and trimming free.

Figure 1 is a flowchart showing a process for making synthetic hair extensions according to one embodiment of the present invention. In this exemplary embodiment, polypropylene resin is first mixed with other raw ingredients 101 and then the mixture is run through an extruder to make polypropylene yarn 102. The polypropylene yarn is grouped into hanks that are each secured and cut 103. Next, the hanks of yarn go through a relaxation tunnel 104 and then are rested 105. After sufficient resting, the resulting fibers are brushed to produce the desired hairstyle 106, and then packaged for sale 107. The brushing can be performed manually by a person or automatically by an electronic (electronically-controlled or computerized) brushing machine.

In this exemplary embodiment, the polypropylene resin is a commercially-available polypropylene pellet resin known as Esenttia 18H86 from Esenttia (of the Ecopetrol Business Group) and supplied by Polipropileno del Caribe S.A. This is a medium melt flow rate polypropylene homopolymer having high cleanness and stable processability, good tenacity/elongation balance, gas fading resistance, and excellent whiteness. In further embodiments, other polypropylene resins are used. In yet other embodiments, nylon or polyester resins are used in place of polypropylene.

In this exemplary embodiment, the Esenttia 18H86 polypropylene pellet resin is mixed with magnesium stearate at 4%, dye at 6%, and flame retardant at 1-2% (percentages by weight relative to weight of polypropylene pellet resin). In further embodiments, other relative percentages of these products are used in the mix, as shown by the ranges in Table 1. Preferably, 50 kg of polypropylene pellet resin is used for each batch, but a batch size of 25-200 kg of polypropylene pellet resin is possible in this embodiment. And other batch sizes are possible in embodiments that use other extruding equipment.

TABLE 1

The magnesium stearate is added to give the resulting fiber greater weight and rigidity, and the dye is used to produce the desired hair color. In one embodiment, the flame retardant is contained in a product known as CESA TH-LIGHT / FR PPA0606535 from Clariant International Ltd. This is a CESA masterbatch product that combines a flame retardant with other additives for providing thermal and UV light stability. The product is a concentrate in pellet form containing a mixture of halogenated compounds for flame retardation and light stabilizers in a polypropylene base resin. In this embodiment, pellets of the CESA masterbatch product are added to the polypropylene pellet resin at 1-4%, and preferably at 2%. In further embodiments, any suitable flame retardant that inhibits or prevents combustion of the plastic can be added to the polypropylene pellet resin at 1-4% (and preferably at 1-2% or 2%), with the addition of thermal and/or UV light stabilizers being optional.

In this exemplary embodiment, the polypropylene pellet resin, magnesium stearate, dye, and flame retardant are placed into a drum and then mixed by a motorized drum tumbler for 15 minutes at ambient temperature (e.g., 15°C-25°C) to produce a homogeneous compound. As shown in Figure 5, the drum tumbler 502 is a machine that automatically mixes the ingredients by rotating one or more of the drums 504. In further embodiments, the mixing is performed for 10-25 minutes at a temperature of 10°C-30°C (preferably about 20°C).

The polypropylene pellet resin mixture is then run through an extruder that uses a melt spinning process to produce polypropylene yarn. Figure 2 shows an exemplary melt spinning process. The polypropylene pellet mixture is fed into a feed hopper 201. The mixture is melted and then a melt spinning pump 202 forces the molten material through the orifices of a spinneret 203. A gear pump is used to press the molten material through the spinneret at a constant rate. After exiting the spinneret, the molten filaments enter a quench air duct 204 a short distance (e.g., 5-20 cm) below the spinneret and are solidified by the air. After leaving the quench air duct, the filament bundle is drawn over one or more godets (rollers) 205 and then wound on spinning packages 206.

In this exemplary embodiment, the extruder is a high/medium-tenacity polypropylene yarn production machine such as the Austrofil HT/MT Multifilament Spinning Plant (e.g., Austrofil HT 2 x 2 C, model 2005) made by SML Maschinengesellschaft mbH of Lenzing, Austria. Figure 3 shows a front view of the polypropylene yarn production machine, Figure 6 shows a side view of an upper portion of the machine, and Figure 7 shows a perspective view of the machine. The specifications of the polypropylene yarn production machine are shown in Table 2. The polypropylene pellet resin mixture is fed into the feed hopper 301 and extruded at a melt temperature of 220°C (428°F). In further embodiments, extrusion is performed at a melt temperature of 190°C-230°C. Following extrusion, the molten material is optionally pressed through a screen belt filter to remove impurities and provide consistent quality.

Then spinning pumps in the electrically heated spinning beam press the molten material with steady and sufficient pressure through four 48-strand spinnerets 302 so as to produce filaments 308 having a filament diameter of 0.6 mm. Two of the spinnerets of the polypropylene yarn production machine are shown in Figure 8. In further embodiments, a filament diameter of 0.4-0.9 mm is used. Upon emerging from the spinnerets 302, the filaments 308 are cooled by a controlled air stream in a quench air duct 303. The filaments are then supplied with spin finish and drawn off to one or more stretching modules 304 via godets (rollers).

In this embodiment, the filaments 308 from each spinneret 302 are supplied to a stretching module 304 that draws them over three pairs of stretching godets 309. This facilitates stretching ratios of up to 1 :8. Optionally, a hot air chamber is provided in the stretching module to increase yarn tenacity. The yarn is then intermingled and wound onto bobbins by one or more winder heads 310. Two winder heads of the polypropylene yarn production machine of this embodiment are shown in Figure 9. This extrusion process produces a continuous final fiber having a denier of 1,700, a tenacity of 2.20 cN/den (2.24 g/den), and 50% stretching or elongation. In further embodiments, the final fiber has denier of 1530-1870, a tenacity of 1.98-2.42 cN/den, and 30%-60% stretching or elongation.

During extrusion, the filaments 308 are preferably lubricated with extrusion oil by an oil dispenser 312 on the extruder in order to make the resulting yarn easier to work with during subsequent processing. The portion of the polypropylene yarn production machine that performs the lubrication is shown in Figure 10. In this exemplary embodiment, 100 kg of Lubristat "PNP-NA" (available from Cempri S.A.S. of Bogota, Colombia) is mixed with 100 kg of water until the mixture is homogenized (approximately 15 minutes). The oil mixture is then supplied to a reservoir on the extruder. During extrusion, a pump delivers the oil mixture to the oil dispenser 312, which lubricates the filaments 308 with the oil mixture during the final cooling in which the yarn becomes solid. The dose rate is 3% oil mixture (for example, 100 kg of extruded filament contains 97 kg of the polypropylene mixture and 3 kg of the oil-water mixture). Lubristat PNP-NA is a lubricant for synthetic fibers that provides lubrication, static control, and cohesion of the fiber, in addition to an excellent touch. These properties are important for obtaining good performance of the yarn during the subsequent processing stages. This lubricant is also easily removable by a conventional wash. In further embodiments, the ratio of oil to water can differ, and the dose rate can also differ (e.g., 1-4% oil mixture, preferably 2% or 3%).

TABLE 2 Capacity 160 kg/h

Raw Material Handling Resin hopper with suction feeder

Extruder diameter: 75mm

Extrusion L/D ratio: 28

Max. screw speed: 160 rpm

incl. static mixer

Melt Filtration optional continuous melt filtration

with SML screen belt

Number of spinning pumps: 4

Spinning Beam

Number of spinning packages: 8

Number of stretching units: 1-4

Stretching Threads per drawing unit: 2 (4)

Draw ratio: infinitely variable

Number of winder heads: 1-4

Threads per winder: 1/2/4

Winding

Core inner diameter: 75mm (84mm)

Bobbin diameter: 300-420mm

Compressor pressure: 7.5bar

Compressed Air Supply Avg. air consumption (incl. intermingling): 550 Nm ³ /h

Peak air consumption: 1000 Nm ³ /h

Water Chiller Cooling Capacity approx. 63,000 kcal/h

The bobbins of yarn are then processed and finished to produce synthetic hair extensions. In particular, a skein winder 1102 is used to roll the yarn, as shown in Figure 11. The yarn is grouped and cut into hanks (loops of yarn) 1202 of 90 grams, which are each secured (e.g., tied by a tie 1204) to prevent the fibers from becoming tangled or separated, as shown in Figure 12. Each hank 1202 is cut in the middle and then the resulting ends (tips) of the fibers are clipped in a custom press 1206, as shown in Figure 13.

The custom press 1206 used in this exemplary embodiment is shown in a top view in Figure 4A and in a side view in Figure 4B. The press 1206 is formed by two flat sheets of cold rolled aluminum 1208 and 1210 held together by a clip 1212 that is riveted 1214 to each of the sheets. In this exemplary embodiment, the top aluminum sheet 1208 is 8" long by 1 3/8" wide and the bottom aluminum sheet 1210 is 8" long by 1 1/2" wide. The back edge 1211 of the bottom sheet 1210 is turned up to form an "L"-shape (i.e., lip) that is sized so as to be flush with the top sheet 1208 when the sheets are pressed together by the clip 1212.

As shown in Figures 14 and 15, the top and bottom sheets 1208 and 1210 are separated and the cut fibers of the hank 1202 are inserted into the press 1206 such that their ends 1203 abut the lip 1211 of the bottom sheet 1210. The two sheets 1208 and 1210 are then clipped onto the fibers such that the two sheets are substantially parallel and generate pressure on the end portions 1205 of the fibers that are clipped (enclosed) in the press. The dimensions of the press are designed so that it holds a set length of the end portions 1205 of the fibers while being able to pass through the furnace without getting stuck. While aluminum allows for good heat regulation, the sheets are made of another material such as stainless steel in further embodiments. Additionally, the sheets have different dimensions in further embodiments (e.g., width increased to hold a greater length of the end portions in the press).

The secured and cut hanks of yarn with the press applied are then run through a fiber relaxation tunnel 1602, which is a specially-designed conveyor furnace as shown in Figure 16. A conveyor belt moves each hank of yarn through the furnace tunnel for six minutes. A series of resistances heat the inside of the tunnel to a temperature of 135°C (275°F). In further embodiments, this relaxation process is performed at a temperature of 110°C-150°C for 2-12 minutes. However, it has been found that the best results are obtained at

approximately 135° C for approximately 6 minutes. In this embodiment, three fans keep the air constantly moving inside the tunnel to guarantee that a steady temperature is maintained during the trip through the tunnel. The heat and constantly moving air inside the tunnel at least partially evaporate the extrusion oil so that the fibers are relaxed and tension is released. Additionally, they relax and contract the fibers so as to produce a thread that detaches properly when being brushed so that the necessary volume can be obtained.

Figures 17 and 18 show hanks that have passed through the relaxation tunnel.

Because the end portions of the fibers are clipped in the press when passing through the tunnel, the fibers remain oriented and the tips (ends) of the fibers do not contract or deform in the tunnel. The press holds and presses the end portions of the fibers during passage through the furnace so that the temperature of the furnace does not act directly on this portion of the fibers. The end result is uneven, natural looking, and softer tips (ends) than the rest of the fibers. This produces extensions with tips having an almost natural finish that resembles human hair. When removing the press after exiting the tunnel, the end portions are straight (ironed) and look like natural human hair because they have an uneven and natural finish. And the resulting tips are smooth because the press prevents or reduces entanglement of the fibers. This facilitates the making of braids, hair styling, and final finishing. The relaxation tunnel (along with the press) provides a much better product as compared to conventional processes that after extrusion pass the thread through rollers with teeth that grind the thread so as to cause irregularities and then comb the cuffs to obtain the volume.

After a hank leaves the relaxation tunnel, the press that holds the end portions is removed and the hank is hung from its middle (e.g., by the tie). The resulting tips are self- ironed (smooth). The hanging fibers rest at ambient temperature (e.g., 15°C-25°C) for 24 hours. In one preferred embodiment, rest is at an average temperature of 18°C (64°F).

During the resting time, the fibers are cooled, relaxed, and extrusion oil is evaporated. This allows the fibers to finish contracting and releasing tension, as shown in Figures 19 and 20. After this rest period, the fibers have the desired final volume and texture. In further embodiments, this resting process is performed for 16-30 hours at a temperature of 10°C- 30°C.

After resting, the fibers in the hank are brushed to style the hair. This brushing can be performed manually (i.e., by hand), or automatically by a brushing machine. This orients the fibers and separates their filaments to provide volume, functionality, and a natural texture. After being brushed, the fibers acquire a volume and natural finish that makes the hair look like human hair and soft to the touch, as shown in Figures 21 and 22. In some embodiments, automated equipment is used to brush the hair extensions.

The resulting synthetic hair extensions are then packaged in a paper insert that contains color information, length measurement, advantages, and qualities, as shown in Figure 23. The paper insert and synthetic hair extension are then placed in a plastic sleeve for preservation.

Accordingly, embodiments of the present invention provide improved synthetic hair extensions and methods for making the same. These synthetic hair extensions feel and look like human hair, and blend well with human hair. It is difficult to tell the difference between the synthetic hair extensions and human hair. The synthetic hair extensions are not deformable, which makes them resistant. Additionally, the synthetic hair extensions are very soft and extremely smooth to work with. They will not cut fingers, which is very important because the hands are a professional's primary working tool. And the user benefits from having a full head of hair. And the softness of the synthetic hair extensions reduces or prevents headaches caused by tightly pulled ponytails or braids. Further, due to its tenacity property, the synthetic hair extensions are stronger and thus extremely functional. For this reason, the synthetic hair extensions of the present invention will completely change the way the hair stylist does braids. The synthetic hair extensions are tangle free, trimming free, waste free, easy to separate, easy brushing, easy to handle, and do not break. These benefits save time when making a full installment of hair extensions. This allows the user to leave earlier and go back to daily activities, and allows the hair stylist to increase revenue and have time for additional customers per day.

The synthetic hair extensions of the present invention are particularly suited for easily creating fancy fashion African-American-style braids and the most well-known African- American-style braids.

The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms "including" and "having," as used herein, are defined as comprising (i.e., open language). The term "coupled," as used herein, is defined as "connected," although not necessarily directly, and not necessarily

mechanically.

All references cited herein are expressly incorporated by reference in their entirety. It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. There are many different features to the present invention and it is contemplated that these features may be used together or separately. Thus, the present invention should not be limited to any particular combination of features or to a particular application. Further, it should be understood that variations and modifications within the spirit and scope of the present invention might occur to those skilled in the art to which the present invention pertains. Additionally, an embodiment of the present invention may not include all of the features described above. Accordingly, all expedient modifications readily attainable by one versed in the art from the disclosure set forth herein that are within the scope and spirit of the present invention are to be included as further embodiments of the present invention.