The present invention relates to applicators for applying cosmetics to human hairs or eyelashes, and specifically to a cosmetic applicator assembly that includes a bi-injection molded polymeric brush complementarily engaged with a twisted wire brush. More specifically, the bi-injection molded polymeric brush of the present invention comprises an elongated polymeric core formed of a first, relatively stiffer polymeric material and multiple protruding polymeric tines formed of a second, relatively softer polymeric material.

A cosmetic brush is typically used for applying cosmetic (e.g., mascara and the like) to an application area, e.g., a user's hairs or eyelashes. Such a cosmetic brush can also be used for separating hairs or eyelashes and removing excess cosmetic therefrom.

One common type of cosmetic brush includes a twisted wire brush formed by first folding a single metallic wire into a generally U-shaped configuration to provide a pair of parallel wire segments, then disposing multiple relatively soft bristles (also referred to as filaments or fibers, which are typically formed of nylon strands) between a portion of a length of the wire segments, which holds or clamps the soft bristles securely at their midpoints, followed by twisting or rotating the wire segments about each other, thereby forming a helical core (also known as a twisted wire core) with soft bristles radially extending therefrom in a helical or spiral manner. The radially extending soft bristles jointly form a bristle portion or a bristle head of the twisted wire brush, which can be used for applying a coating of mascara or other cosmetic onto hairs or eyelashes of a user. The soft and flexible bristles of the twisted wire brush are particularly effective in providing a good grip over the fine hairs or eyelashes and allowing the mascara to thoroughly coat over the hairs or eyelashes.

However, the mascara-coated hairs or eyelashes have a tendency to stick to one another and form unaesthetic clumps. The above-described twisted wire brushes with soft bristles, although effective in applying mascara onto the hairs or eyelashes, cannot sufficiently separate the clumped hairs or eyelashes from one another. In order to eliminate or reduce the clumping, a post-application doctoring or arrangement step can be carried out to separate the clumped hairs or eyelashes, by using a separate twisted wire brush with relatively stiff bristles or more preferably, a separate comb with stiff teeth.

To avoid the inconvenience of having to conduct each of the application and doctoring/arrangement steps using separate tools, it is desirable to integrate a twisted wire brush of soft bristles with a comb of stiff teeth to form a single cosmetic applicator. Various prior art references have disclosed such integrated cosmetic applicators with different arrangements and constructions of the twisted wire brush and the comb. For example, U.S. Patent No. 3,921,650 discloses a cosmetic applicator having a handle and a rod, while one end of the rod contains a comb with relatively stiff teeth extending perpendicularly from one side of a base portion, a twisted wire brush with relatively soft bristles extending perpendicularly from the other side of the base portion, and a serrated portion at the tip of the rob. U.S. Patent No. 6,408,857 discloses a cosmetic applicator including a twisted wire brush with relatively soft bristles that is bent into a closed loop, and into this loop is inserted a comb with relatively stiff teeth extending from either one side or both sides. The teeth of the comb are offset from the bristles of the twisted wire brush, so that the cosmetic application has a cross-section that resembles either a "T" (if the comb only has teeth extending from one side) or a "+" (if the comb has teeth extending from both sides). U.S. Patent Application Publication No. 2004/0221865 discloses a mascara brush containing both an application brush part and an arrangement brush part. The arrangement brush part includes a comb with relative stiff teeth formed by injection molding, while the application brush part includes a twisted wire brush with relatively soft bristles. The arrangement brush part and the application brush part are affixed to each other so that the teeth of the comb are offset from the bristles of the twisted wire brush, thereby forming a brush head with both stiff teeth and soft bristles.

Combs in the above-described prior art integrated cosmetic applicators are typically formed by a single injection molding process, in which a hot molten polymer is first injected into a mold and then cooled down to form a molded article. Correspondingly, both the teeth of the comb and the core of the comb are formed by the same polymer. Because the core of the comb provides structural support for the entire comb, the polymer that forms such core has to be hard enough to provide the required structural support. However, the teeth of the comb, when formed of the same hard polymer, may be too stiff or rigid that they lose grip on the hairs or eyelashes and are not able to get between the clumped hairs or eyelashes. Correspondingly, combs of the prior art integrated cosmetic applicators described hereinabove may not be effective in separating the clumped hairs or eyelashes.

There is therefore a continuing need for improved cosmetic applicators of dual functions, i.e., which can be used for performing both the cosmetic application function and the hair/eyelash arrangement function, but without the above-described drawbacks of the prior art applicators.

In one aspect, the present invention relates to an integrated cosmetic applicator assembly containing a polymeric brush and a twisted wire brush. The polymeric brush has an elongated polymeric core and multiple polymeric tines protruding from the elongated polymeric core. More specifically, the elongated polymeric core comprises a first polymeric material of a first tensile modulus, while at least some of the polymeric tines comprise a second polymeric material of a second tensile modulus that is smaller than the first tensile modulus. The twisted wire brush comprises a metal wire core and multiple bristles protruding from the metal wire core. The elongated polymeric core of the polymeric brush is adapted for complementarily engaging at least a portion of the metal wire core of the twisted wire brush to form the integrated cosmetic applicator assembly.

The integrated cosmetic applicator assembly of the present invention can be used to effectively perform both the application function and the doctoring/arrangement function. The twisted wire brush with relatively soft bristles is useful for applying a liquid or semi-liquid cosmetic product (e.g., mascara) to human hairs or eyelashes, while the polymeric brush with relatively stiff tines (in comparison with the bristles of the twisted wire brush) is useful for subsequent separation and arrangement of such hairs or eyelashes. Alternatively, the polymeric brush may comprise relatively soft tines useful for applying the cosmetic product to human hairs or eyelashes, while the twisted wire brush may comprise relative stiff bristles useful for subsequent separation and arrangement of the hairs or eyelashes. More importantly, by forming at least some of the protruding tines of the polymeric brush with a polymeric material (i.e., the second polymeric material) relatively softer than the polymeric material used for forming the core of the polymeric brush (i.e., the first polymeric material), the polymeric brush achieves a much better grip on the hairs or eyelashes, while the core of the polymeric brush can continue to provide the required structural support so that the polymeric brush of the present invention can still retain its overall shape during the doctoring/arrangement step, without significant bending or distortion.

Note that the term "complementarily engaging" or "complementarily engaged" as used herein refers to formation of an interlocking relationship between two or more complementary elements or structures. Further, the term "polymer" or "polymeric" as used herein refers to any material, composition, structure, or article that comprises one or more polymers, which can be homopolymers, copolymers, or polymer blends.

In another aspect, the present invention relates to a polymeric cosmetic brush for use in combination with a twisted wire cosmetic brush. Such polymeric cosmetic brush contains an elongated polymeric core having a longitudinal axis and multiple polymeric tines protruding from the elongated polymeric core. The elongated polymeric core comprises a first polymeric material of a first tensile modulus, while at least some of the polymeric tines comprise a second polymeric material of a second tensile modulus that is less than the first tensile modulus. The elongated polymeric core further comprises one or more protrusions and/or recesses adapted for complementarily engaging one or more corresponding portions of a twisted wire brush.

In still another aspect, the present invention relates to simply a polymeric cosmetic brush comprising an elongated polymeric core having a longitudinal axis and multiple polymeric tines protruding from the elongated polymeric core, such elongated polymeric core comprising a first polymeric material of a first tensile modulus, while at least some of the polymeric tines comprising a second polymeric material of a second tensile modulus that is less than the first tensile modulus.

In a further aspect, the present invention relates to a method of making a cosmetic applicator assembly, comprising:

• forming a polymeric brush comprising an elongated polymeric core and multiple polymeric tines protruding from the elongated polymeric core, wherein the elongated polymeric core comprises a first polymeric material of a first tensile modulus, wherein at least some of the polymeric tines comprise a second polymeric material of a second tensile modulus that is less than the first tensile modulus, wherein the elongated polymeric core further comprises one or more protrusions and/or recesses adapted for complementarily engaging one or more corresponding portions of a twisted wire brush;
• forming a twisted wire brush comprising a metal wire core and multiple bristles protruding from the metal wire core; and
• complementarily engaging the elongated polymeric core of the polymeric brush with one or more portions of the twisted wire brush to form the cosmetic applicator assembly.

Preferably, but not necessarily, the polymeric brush as described hereinabove is formed by a bi-injection molding process, in which two or more different polymeric materials are simultaneously injection molded to form one article.

Other aspects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.

• FIG. 1A is a perspective view of an exemplary polymeric brush, according to one embodiment of the present invention.
• FIG. 1B is a top view of the exemplary polymeric brush of FIG. 1A.
• FIG. 1C is a representative or schematic cross-sectional view of the exemplary polymeric brush of FIGS. 1A and 1B, along the line A-A in FIG. 1B.
• FIG. 2A is a side view of an exemplary twisted wire brush, according to one embodiment of the present invention.
• FIG. 2B is a representative or schematic cross-sectional view of the exemplary twisted wire brush of FIG. 2A, along the line B-B.
• FIG. 3A is a side view of a cosmetic applicator assembly formed by complementarily engaging the polymeric brush of FIGS. 1A-1C with the twisted wire brush of FIGS. 2A-2B, according to one embodiment of the present invention.
• FIG. 3B is a perspective view of the cosmetic applicator assembly of FIG. 3A.
• FIG. 3C is a representative or schematic cross-sectional view of the cosmetic applicator assembly of FIGS. 3A-3B, alone the line C-C in FIG. 3A.
• FIG. 4 is a side view of a cosmetic package comprising the cosmetic applicator assembly of FIGS. 3A-3C as mounted on one end of a rod, while a cap is mounted at the other end of the rod and adapted for complementarily engaging a neck portion of a cosmetic container, according to one embodiment of the present invention.
• FIGS. 5-6 are perspective views of exemplary polymeric brushes with polymeric tines of alternative shapes, according to alternative embodiments of the present invention.
• FIG. 7A is a perspective view of an exemplary polymeric brush having curved polymeric tines, according to one embodiment of the present invention.
• FIG. 7B illustrates the relative positions of two representative tines of the exemplary polymeric brush of FIG. 7A, as located adjacent to each other in the same row.

In the following description, numerous specific details are set forth, such as particular structures, components, materials, and dimensions, in order to provide a thorough understanding of the present invention. However, it will be appreciated by one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known structures, components, materials, or dimensions may be described in less detail here in order to avoid obscuring elements of the present invention.

As mentioned hereinabove, the present invention provides an integrated cosmetic applicator assembly containing both a twisted wire brush and a bi-injection molded polymeric brush. Specifically, the bi-injection molded polymeric brush of the present invention contains an elongated polymeric core formed of a first, relatively stiff polymeric material and multiple protruding polymeric tines formed of a second, relatively soft polymeric material. The softer tines of such a bi-injection molded polymeric brush are believed to provide a much better grip on the hairs or eyelashes and is therefore more effective in separating clumped hairs or eyelashes, while the stiff core of such a bi-injection molded polymeric brush can continue to provide the required structural support, so that the polymeric brush of the present invention can still retain its overall shape during the doctoring/arrangement step, without significant bending or distortion.

FIGS. 1A-1C shows various views of a bi-injection molded polymeric brush 1, according to one exemplary embodiment of the present invention. The bi-injection molded polymeric brush 1 includes a handle portion 10 and a brush head portion 20. The brush head portion 20 has an elongated polymeric core 24 and multiple polymeric tines 26, which protrude perpendicularly from the elongated polymeric core 24.

Specifically, the elongated polymeric core 24 is formed of a first, relatively stiff polymeric material, while at least some (and preferably all) of the multiple polymeric tines 26 are formed of a second, relatively soft polymeric material. The first, relatively stiff polymeric material can be characterized by a first tensile modulus preferably ranging from about 800 MPa to about 3000 MPa, while the second, relatively soft polymeric material can be characterized by a second tensile modulus that is less than the first tensile modulus, which preferably ranges from about 35 MPa to about 1200 MPa. More preferably, the first tensile modulus ranges from about 1000 MPa to about 2000 MPa, and the second tensile modulus ranges from about 95 MPa to about 570 MPa. Most preferably, the first tensile modulus ranges from about 1250 MPa to about 1600 MPa, and the second tensile modulus ranges from about 200 MPa to about 280 MPa. Exemplary polymers that can be used as the first polymeric material in the present invention include, but are not limited to: ethylene-propylene diene monomer or EDPM rubber, ethylene vinyl acetate copolymer, acrylonitrile polymers, polyamide, polycarbonate, polyester, polyethylene terephthalate, polymethyl methacrylate, polyolefins (such as, for example, polyethylene and polypropylene), polyoxymethylene, polystyrene, polyurethane, and acrylonitrile butadiene styrene. Exemplary polymers that can be used as the second polymeric material in the present invention include, but are not limited to: silicone elastomers, thermoplastic elastomers (such as, for example, styrene-ethylenebutylene-styrene or SEBS block copolymer), vinyl elastomers (such as ethyl vinyl acetate or EVA), thermoplastic polyester elastomers (such as those commercialized under the trademark Hytrel^® by Du Pontde Nemours), thermoplastic polyurethane elastomers (such as those commercialized under the trademark Pellethane^® by Dow Chemical Company), acrylonitrile polymers, and ethylene propylene diene monomer or EDPM rubber. It is important to note that the list of polymeric materials provided hereinabove are only for illustration purposes, and any other suitable polymeric material known in the art can be used in place of or in combination with the above-listed materials.

In a preferred embodiment of the present invention, the first polymeric material is polypropylene, and the second polymeric material is a silicone elastomer or a thermoplastic polyester elastomer. In an alternative embodiment, the first polymeric material is polycarbonate or acrylonitrile butadiene styrene, and the second polymeric material is a thermoplastic polyurethane elastomer. In a further alternative embodiment, the first polymeric material is polyoxymethylene, and the second polymeric material is a thermoplastic polyester elastomer.

The elongated polymeric core 24 of the polymeric brush 1 may comprise one or more protrusions and/or recesses for complementarily engaging one or more corresponding portions of a metal wire core of a twisted wire brush. On one hand, the term "protrusion" as used herein broadly covers any protruding structure, which includes, but is not limited to: clips, hooks, spikes, nodes, lugs, pins, and tabs. On the other hand, the term "recess" as used herein broadly covers any recessing structure, which includes, but is not limited to: surface openings (such as grooves, pits or holes), loops, bores, central lumens, and clearances. For example, the elongated polymeric core 24 may comprise a surface groove that extends along the longitudinal axis of the polymeric core 24, and at least one portion of the metal wire core of the twisted wire brush can be inserted into such surface groove, as described by U.S. Patent No. 3,921,650.

The elongated polymeric core 24 may comprise an annular surface groove, and at least one portion of the metal wire core of the twisted wire brush forms a loop that is adapted to engage such annular surface groove of the elongated polymeric core 24, as described by U.S. Patent No. 6,408,857. Preferably, but not necessarily, the elongated polymeric core 24 contains a central lumen 22 with at least one opening at one side of the elongated polymeric core 24, as illustrated in FIGS. 1A-1C. Such a central lumen 22 may extend through the entire length of the elongated polymeric core 24, or it may extend only through a portion thereof and close at a distal end 24T of the polymeric core 24, as shown in FIGS. 1A-1B. The opening in the central lumen 22 is preferably characterized by an angel a (shown in FIG. 1 C), which ranges from about 1° to about 90°, more preferably from about 15° to about 75°, and most preferably from about 30° to about 60°.

The handle portion 10 of the exemplary polymeric brush 1 includes a central lumen 12 that connects with the central lumen 22 of the elongated polymeric core 24. Further, the central lumen 12 has a narrow aperture or slit 14 that also connects with the opening of the central lumen 22 of the elongated polymeric core 24. The central lumens 12 and 22 in the polymeric brush 1 are adapted for accommodating the metal wire core of a twisted wire brush, with which the polymeric brush 1 is to be complementarily engaged. The slit 14 at the handle portion 10 allows the soft bristles of the twisted wire brush to pass through the handle portion 10 with little or no bending, and the opening of the central lumen 22 in the elongated polymeric core 24 accommodates the soft bristles of the twisted wire brush and allow them to fully extend outward from the elongated polymeric core 24.

FIG. 2A shows the side view of an exemplary twisted wire brush 2, with which the polymeric brush 1 of FIGS. 1A-1C is to be complementarily engaged. Specifically, the twisted wire brush 2 includes a metal wire core 30, which is formed by folding a single metallic wire into a U-shape to provide a pair of parallel wire segments, and then twisting or rotating the pair of wire segments about each other in a helical manner. The twisted wire brush 2 also includes multiple soft and flexible bristles 42 and 44 of different lengths, which extend radially from the metal wire core 30. Specifically, the longer bristles 42 are arranged at one side of the metal wire core 30, while the shorter bristles 44 are arranged at the other side of the metal wire core 30, as shown in the cross-sectional view of FIG. 2B. More specifically, when viewed at the cross-section, the longer bristles 42 jointly form a fan-shaped configuration around the metal wire core 30, and such configuration is preferably characterized by an angel that is the same as the angle a shown in FIG. 1C.

Correspondingly, the twisted wire brush 2 of FIG. 2A-2B can be complementarily engaged with the polymeric brush 1 of FIG. 1A-1C to form a cosmetic applicator assembly 3, as shown in FIGS. 3A-3C. Specifically, the shorter bristles 44 and the metal wire core 30 of the twisted wire brush 2 can fit into the central lumen 22 of the polymeric brush 1, while the longer bristles 42 of the twisted wire brush 2 can fully extend outward from the opening of the central lumen 22 of the polymeric brush 1. The metal wire core 30 of the twisted wire brush 22 may extend along the entire length of the polymeric brush 1 through the central lumens 22 and 12 of the polymeric brush 1 and further outwards. The resulting cosmetic applicator assembly 3 therefore has the polymeric tines 26 on one side and the soft bristles 42 on the other side, as shown in FIG. 3C.

It is important to note that the above-described specific configurations for complementarily engaging the elongated polymeric core of the polymeric brush and the metal wire core of the twisted wire brush are only described herein for illustrative purposes. Such specific configurations should not be construed in any manner as limiting the broad scope of the present invention, and any other means or arrangement that is obvious to a person ordinarily skilled in the art for complementarily engaging the elongated polymeric core of the polymeric brush and the metal wire core of the twisted wire brush is also possible.

The polymeric tines of the polymeric brush may be formed of either the same or different polymeric materials. In a specific embodiment of the present invention, all of the protruding polymeric tines of the polymeric brush comprise the second, relatively soft polymeric material. In an alternative embodiment of the present invention, some of the protruding polymeric tines of the polymeric brush comprise the second, relatively soft polymeric material, while other tines may comprise the first, relatively stiff polymeric material that is used to form the elongated polymeric core of the polymeric brush. In a further alternative embodiment of the present invention, some of the protruding polymeric tines may even comprise a third polymeric material that is different from the first and second polymeric materials. Such different polymeric tines of different compositions can be arranged in any configurations with respective to one another, either randomly or into an orderly pattern. For example, the polymeric tines of the same composition may be arranged into one or more straight rows that are substantially parallel to the longitudinal axis of the elongated polymeric core of the polymeric brush, or into one or more spirals that wind around the longitudinal axis of the elongated polymeric core. Note that the term "substantially perpendicular" or "substantially parallel" as used herein refers to less than 10 degrees of deviation from a perpendicular or parallel direction.

The polymeric brush of the present invention may have tines of any size, shape, and spacing suitable for its intended functions, e.g., application, arrangement, and/or separation of human hairs or eyelashes. Preferably, but not necessarily, the tines of the polymeric brush of the present invention have an average height ranging from about 0.1 mm to about 10 mm, more preferably from about 0.5 mm to about 7 mm, and most preferably from about 0.8 mm to about 5 mm. The average cross-sectional diameter of the polymeric tines preferably ranges from about 0.1 mm to about 2 mm, more preferably from about 0.2 mm to about 1.5 mm, and most preferably from about 0.3 mm to about 0.9 mm. The polymeric brush preferably has cylinder-shape tines with tapered ends, as shown in FIGS. 1A-3C. Alternatively, the polymeric brush may have spike-shaped polymeric tines 26', as shown in FIG. 5. For a further example, the polymeric brush of the present invention may have fin-shaped polymeric tines 26", as shown in FIG. 6. Note that the polymeric tines of the polymeric brush can either have the same size and/or shape, or have different sizes and/or shapes. The tines can be spaced or arranged in any suitable manner. For example, the tines can be arranged into straight rows that are substantially parallel to the longitudinal axis of the polymeric brush (as shown in the drawing figures described hereinabove), or zigzagged rows with center lines substantially parallel to the longitudinal axis of the polymeric brush, or spiral rows that wind around the longitudinal axis of the polymeric brush. Preferably, but not necessarily, the polymeric tines can be arranged substantially perpendicular to the surfaces of the elongated polymeric core of the polymeric brush, as shown in the above-described drawings. Alternatively, the tines can be tilted or slanted from the surfaces of the elongated polymeric core by any angle ranging from about 5 degrees to about 85 degrees. For example, tines in the same row may curve or bend in such a manner that top portions of adjacent tines in the same row are curved away from each other with respect to the center line of the row, as described by U.S. Patent No. 6,581,610, and as illustrated in FIGS. 7A and 7B. Specifically, tines 126A and 126B in the same row 124 can be curved away from each other with respect to the center line of the row 124 (as indicated by the dotted line).

The cosmetic applicator assembly as described hereinabove may further comprise one or more optional components, such as, for example, a cap 54 and a rod 52 that extends from the cap 54, as shown in FIG. 4. The rod 52 may contain a recess or protrusion adapted for complementarily engaging the handle portion 10 of the polymeric brush 1 and the metal wire core 30 of the twisted wire brush 2. The cap 54 is adapted for complementarily engaging a neck portion 62 of a cosmetic container 60 that contains therein a liquid or semi-liquid cosmetic, such as mascara. Preferably, but not necessarily, the cap 54 contains internal threads (not shown), and the neck portion 62 of the container 60 contains external threads 64 that are complementary to the internal threads of the cap 54, so that the cap 54 can be screwed onto the container 60 in a leak-tight manner. Note that other affixation means or mechanisms, either mechanical or adhesive-based, can be readily used for affixing or otherwise engaging the cap 54 with the neck portion 62 of the container 60. The neck portion 62 of the container 60 may also contain one or more internal wiper structures (not shown) for removing excess cosmetic from the cosmetic applicator assembly 3 when the cosmetic applicator assembly is being removed from the container 60.

The polymeric brush of the present invention, as described hereinabove, can be readily formed by a bi-injection molding process, in which two different thermoplastic or thermosetting polymers are injection-molded together to form a single article, i.e., the polymeric brush of the present invention. First, a first polymer with a relatively high tensile modulus can be melted and injected at high pressure into a first mold, which preferably contains two or more solid parts that are complementarily engaged with one another to define at least a first cavity therein. The first cavity may correspond to the desired shape of the elongated polymeric core to be formed. After a cooling period sufficient to allow the molten first polymer to solidify (either completely or partially), the two or more solid parts of the first mold are disengaged from one another to expose an elongated polymeric core formed by the solidified first polymer. The elongated polymeric core so formed is then transferred into a second mold, which also contains two or more solid parts complementarily engaged with one another to define cavities that not only accommodate the elongated polymeric core already formed, but also define the desired shapes of the polymeric tines to be formed. A second polymer with a relatively low tensile modulus, preferably already melted, can be injected at high pressure into the second mold. After the molten second polymer cools down and solidifies (either completely or partially), the two or more solid parts of the second mold are disengaged from one another, thereby exposing multiple polymeric tines that have been molded over the elongated polymeric core to form the polymeric brush of the present invention. In a particular preferred embodiment of the present invention, the time interval between the first and second molding step is relatively short, e.g., less than 20 minutes, more preferably less than 10 minutes, and most preferably less than 2 minutes, so that the surface of the elongated polymeric core is still hot from the first molding step when the second molding commences. In this manner, the surface energy of the elongated polymeric core remains relatively high when the molten second polymer is injected into the second mold, which allows the second polymer to readily adhere to the surface of the elongated polymeric core. The polymeric tines can therefore be adhered to the surface of the elongated polymeric core without the need for any adhesive. Alternatively, the surface of the elongated polymeric core may contain any suitable patterns (e.g., recesses or grooves) for increasing the adhesion or attachment between the polymeric tines and the elongated polymeric core.