COSMETIC BRUSH FIBER WITH STAR-SHAPED CROSS SECTION

Abstract

A cosmetic brush fiber includes five substantially parallel outer edges extending along a length of the cosmetic brush fiber; and five substantially parallel inner edges extending along the length of the cosmetic brush fiber, wherein the cosmetic brush fiber defines a star-shaped transverse cross section.

Claims

1. A cosmetic brush fiber comprising: five substantially parallel outer edges extending along a length of the cosmetic brush fiber; and five substantially parallel inner edges extending along the length of the cosmetic brush fiber, wherein the cosmetic brush fiber defines a star-shaped transverse cross section.

2. The cosmetic brush fiber of claim 1, further comprising ten bristle walls, each of the bristle walls extending between one of the outer edges and an adjacent one of the inner edges, each of the bristle walls extending along the length of the cosmetic brush fiber.

3. The cosmetic brush fiber of claim 2, further defining five substantially parallel indentations extending along the length of the cosmetic brush fiber.

4. The cosmetic brush fiber of claim 3, wherein each of the five substantially parallel indentations defines a substantially triangular cross section.

5. The cosmetic brush fiber of claim 4, wherein each of the bristle walls is angled inward toward a center axis of the cosmetic brush fiber.

6. The cosmetic brush fiber of claim 5, wherein: a pair of the bristle walls can be formed between an adjacent pair of the outer edges; and each of the indentations can be formed between the pair of the bristle walls.

7. The cosmetic brush fiber of claim 1, wherein the star-shaped transverse cross section defines five corner vertices and ten sides.

8. The cosmetic brush fiber of claim 7, wherein: the star-shaped transverse cross section defines a pentagram; and each of the five corner vertices defines an interior vertex angle of 36°.

9. The cosmetic brush fiber of claim 1, wherein the cosmetic brush fiber is crimped to provide a wave substantially along the length of the cosmetic brush fiber.

10. The cosmetic brush fiber of claim 1, wherein the cosmetic brush fiber defines a first end and a second end opposite the first end, and wherein a short tip is defined at the first end.

11. The cosmetic brush fiber of claim 1, wherein the cosmetic brush fiber comprises at least one of polybutylene terephthalate, polyethylene terephthalate, nylon, Sorona®, and Natrafil®.

12. An extrusion plate for extruding a cosmetic brush fiber, the extrusion plate comprising: a plate body; and a plurality of extrusion holes formed through the plate body, each of the extrusion holes defines a star shape, each of the star shapes defining five corner vertices and ten sides; wherein each of the extrusion holes are configured to form an extruded cosmetic brush fiber having a star-shaped transverse cross section.

13. The extrusion plate of claim 12, wherein the extrusion plate is substantially circular in shape, the extrusion plate defining a substantially circular outer edge.

14. The extrusion plate of claim 13, wherein the plurality of extrusion holes surround a center region of the plate body, and wherein none of the extrusion holes are formed through the center region of the plate body.

15. The extrusion plate of claim 14, wherein the center region of the plate body is substantially circular in shape.

16. The extrusion plate of claim 14, wherein the extrusion holes are formed through the plate body between the substantially circular outer edge and the center region.

17. The extrusion plate of claim 14, wherein the extrusion holes are offset radially inward from the substantially circular outer edge by an annular rim of the plate body.

18. The extrusion plate of claim 12, wherein: each of the star shapes defines a pentagram shape; and each of the five corner vertices defines an interior vertex angle of 36°.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The features and components of the following figures are illustrated to emphasize the general principles of the present disclosure. Corresponding features and components throughout the figures may be designated by matching reference characters for the sake of consistency and clarity.

[0075] FIG. 1 illustrates an example brush assembly 10, including bristles 20, a ferrule 30, and a handle 40. The bristles 20 include multiple individual elongate bristle elements discussed in more detail later. The ferrule 30 attaches the bristles 20 relative to the handle 40, such that a user (not shown) can grasp the handle 40 and apply cosmetic product to the bristles 20, and thereafter from the bristles 20 to the user's face (not shown).

[0076] FIG. 2 illustrates an example bristle 20 (aka fiber 20) with a triangular transverse cross section. This figure is not to scale. In this embodiment the triangular transverse cross section is that of an equiangular triangle. It should be understood that an equiangular triangle is a triangle where all three interior angles are equal in measure. Because the interior angles of any triangle always add up to 180 degrees, each angle is always a third of that, or 60 degrees. The dimension D in this figure is the smallest distance (aka length) between any two of the three parallel edges of the bristle 20. These bristles are contemplated for use in the bristles 20 noted above.

[0077] FIG. 3 illustrates an extrusion plate 100.

[0078] FIG. 4 illustrates the inlet side of the extrusion plate 100.

[0079] FIG. 5 illustrates the outlet side of the extrusion plate 100, which includes a plurality of extrusion holes 102.

[0080] FIG. 6 is a close up partial view of that shown in FIG. 5, illustrating the extrusion holes 102 on the outlet side of the extrusion plate 100.

[0081] FIG. 7 shows various “short” tip dimensions for PBT round cross section fibers/bristles.

[0082] FIG. 8A is a perspective view of a quadrangular brush fiber, according to an aspect of the present disclosure.

[0083] FIG. 8B is an end view of the quadrangular brush fiber of FIG. 8A.

[0084] FIG. 8C is a side view of cosmetics brush, according to an aspect of the present disclosure, comprising a bundle of the quadrangular brush fibers of FIG. 8A, a ferrule, and handle.

[0085] FIG. 9A is a perspective view of the quadrangular brush fiber, according to another aspect of the present disclosure.

[0086] FIG. 9B is an end view of the quadrangular brush fiber of FIG. 9A.

[0087] FIG. 10 is a cross sectional view of an extrusion plate, according to an aspect of the present disclosure.

[0088] FIG. 11 is a perspective view of a brush fiber with a star-shaped cross-section, according to an aspect of the present disclosure.

[0089] FIG. 12 is an end view of a plurality of the brush fibers of FIG. 11.

DETAILED DESCRIPTION AND BEST MODE OF IMPLEMENTATION

[0090] The present disclosure can be understood more readily by reference to the following detailed description, examples, drawings, and claims, and the previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this disclosure is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, and, as such, can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0091] The following description is provided as an enabling teaching of the present devices, systems, and/or methods in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the present devices, systems, and/or methods described herein, while still obtaining the beneficial results of the present disclosure. It will also be apparent that some of the desired benefits of the present disclosure can be obtained by selecting some of the features of the present disclosure without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present disclosure are possible and can even be desirable in certain circumstances and are a part of the present disclosure. Thus, the following description is provided as illustrative of the principles of the present disclosure and not in limitation thereof.

[0092] As used throughout, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “an element” can include two or more such elements unless the context indicates otherwise.

[0093] Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0094] For purposes of the current disclosure, a material property or dimension measuring about X or substantially X on a particular measurement scale measures within a range between X plus an industry-standard upper tolerance for the specified measurement and X minus an industry-standard lower tolerance for the specified measurement. Because tolerances can vary between different materials, processes and between different models, the tolerance for a particular measurement of a particular component can fall within a range of tolerances.

[0095] As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0096] The word “or” as used herein means any one member of a particular list and also includes any combination of members of that list. Further, one should note that conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain aspects include, while other aspects do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more particular aspects or that one or more particular aspects necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular aspect.

[0097] Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific aspect or combination of aspects of the disclosed methods.

[0098] The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the disclosure are shown. The invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0099] Reference is now made to the figures, in which like elements indicate like elements throughout the several views.

[0100] General Operating Environment

[0101] As will be seen, discussion will be made herein regarding bristles for use in cosmetic brushes of the like, said bristles having a triangular cross section. Reference is made to FIG. 1, which illustrates an example brush assembly 10, including bristles 20, a ferrule 30, and a handle 40. The bristles 20 include multiple individual elongate bristle elements. The ferrule 30 attaches the bristles 20 relative to the handle 40, such that a user (not shown) can grasp the handle 40 and apply cosmetic product to the bristles 20, and thereafter from the bristles 20 to the user's face (not shown).

[0102] The Triangular Fiber (aka Triangular Bristle)

[0103] Reference is now made to FIG. 2, which illustrates an example triangular bristle 21 (aka triangular fiber 21) with a triangular transverse cross section. This figure is not to scale. In this embodiment the triangular transverse cross section is that of an equiangular triangle. It should be understood that an equiangular triangle is a triangle where all three interior angles are equal in measure. Because the interior angles of any triangle always add up to 180 degrees, each angle is always a third of that, or 60 degrees. The dimension D in this figure is the smallest distance (aka length) between any two of the three parallel edges of the bristle 20. These bristles are contemplated for use in the bristles 20 noted above.

[0104] Uses of the Triangular Bristles

[0105] Contemplated herein is the use of a triangular bristle such as 21 in a cosmetic brush such as brush assembly 10 in FIG. 1, to apply cosmetic products to the skin.

[0106] Mixture with Other Bristles

[0107] Under one configuration, the triangular section fibers 21 may be used alone, that is, no other types of bristles may be used in the bristles 20.

[0108] Under another configuration the triangular section fibers 21 may be used in a blend of fibers which might contain a percentage of triangular section fibers and a percentage of circular transverse section PBT fibers (such as are commonly used for makeup brushes).

[0109] Advantages of the Triangular Bristles

[0110] The cosmetic industry is getting more and more involved in environmentally friendly manufacture/products and animal cruelty issues.

[0111] For this reason, the inventors contemplate making brushes with PBT, instead of animal hair. The challenge of doing so is that the animal hair provides more powder pick up compared to conventional PBT, because the animal hair has a texture on the surface in part due to the presence of cuticles. Extruded PBT does not have such a surface texture.

[0112] The triangular bristles increase the powder pick up power of the brush, because the shape of each bristle (three parallel edges along the length of the bristle) is capable of scratching the surface of the press powder product (the triangular fiber shape “scratches” more compared to a circular section fiber).

[0113] Said another way, the triangular fiber can be used for animal hair substitution because of its ability of picking up powder better than the commonly used circular section PBT.

[0114] Dimensions of the Triangular Bristles

[0115] Reference is again made to FIG. 2, which illustrates an example bristle 20 (aka fiber 20) with a triangular transverse cross section. This figure is not to scale. In this embodiment the triangular transverse cross section is that of an equiangular triangle. It should be understood that an equiangular triangle is a triangle where all three interior angles are equal in measure. Because the interior angles of any triangle always add up to 180 degrees, each angle is always a third of that, or 60 degrees. The dimension D in this figure is the smallest distance (aka length) between any two of the three parallel edges of the bristle 20.

[0116] The sizes of the dimension D is contemplated to include the following lengths: 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm 0.09 mm, and 0.1 mm. Another way of saying this is that the triangular transverse cross sections which define an equiangular triangle have sides each having a transverse measured length being greater than or equal to 0.05 mm and less than or equal to 0.1 mm. Each of these sizes would provide different advantages.

[0117] Composition of Fibers

[0118] The composition of the fibers is in one configuration to be PBT (Polybutylene Terepthalate).

[0119] However, other materials and better resins are contemplated.

[0120] Some cosmetic filaments are made with Nylon, although the elasticity and retention of the material is not as good as PBT.

[0121] DuPont has two cosmetic filaments named Sorona and Natrafil. The two are not PBT and they could be extruded in a triangular section.

[0122] Extrusion of Fibers

[0123] The manufacture of the fibers is done by PBT extrusion techniques such as known in the art, such as using a triangular plate tooling to achieve the triangular PBT section of the fiber.

[0124] A “wave” can be provided in the fiber and is achieved with a conventional crimping method.

[0125] The Tipping Process as Applied to Round Bristles

[0126] Disclosed is the use of a NaOH solution used to dip the tips of the hair into to eat away at the tips which gives the fiber a softer feel on the face. This may be understood as providing a “short” tip to the fiber/bristle.

[0127] In one embodiment of the present disclosure, a chemical tipping process is used to provide similar short tips to the synthetic fiber. Here is a description of the “short tip” tipping process for the following two types of PBT fibers having round cross sections: [0128] 0.05 mm diameter, 40 mm long [0129] 0.07 mm diameter, 40 mm long

[0130] Hair Dimension 0.05 mm Diameter, 40 mm Long

[0131] Reference is made to FIG. 7. Here are certain specifications for this diameter fiber and its related tipping processes: [0132] Tip type: Short Tip [0133] Tipping solution: NaOH (Sodium hydroxide), having a concentration of 44.5+/−2, diluted with water. [0134] Concentration: 44.5+/−2 percent [0135] Temperature: 135′C+/−2 degrees C. [0136] Time: 17 min+/−1 min [0137] Length tip is dipped into solution: 5 mm.sup.˜6 mm+/−1 mm [0138] Final tip length: 1 mm+/−0.2 mm

[0139] The process is as follows. A PBT fiber having a dimension of 0.06 mm diameter and 40 mm long is suspended from above a tipping solution such that a downwardly extending end of the fiber can be dipped into the solution. The tipping solution is NaOH (sodium hydroxide) having a concentration of 44.5+/−2, diluted with water, at a temperature of 135′C+/−2. The downwardly extending end of the fiber is dipped into the tipping solution for about 17 min+/−1 min. The length of the tip which is dipped into solution is 5 mm.sup.˜6 min+/−1 mm. The final tip length is approximately 1 mm+/−0.2 mm. Said another way, the solution removes approximately 4 mm and 1 mm is left. This is the Z dimension in FIG. 7.

[0140] Hair Dimension 0.07 mm Diameter, 40 mm Long

[0141] Reference is made to FIG. 7. Here are certain specifications for this diameter fiber and its related tipping processes: [0142] Tip type: Short Tip [0143] Tipping solution: NaOH (Sodium hydroxide), having a concentration of 44.5+/−2, diluted with water. [0144] Concentration: 44.5+/−2 percent [0145] Temperature: 132′C+/−2 degrees C. [0146] Time: 17 min+/−1 min. [0147] Length tip is dipped into solution: 5 mm.sup.˜6 mm+/−1 mm [0148] Final tip length: 1 mm+/−0.2 mm

[0149] The process is as follows. A PBT fiber having a dimension of 0.075 mm diameter and 40 mm long is suspended from above a tipping solution such that a downwardly extending end of the fiber can be dipped into the solution. The tipping solution is NaOH (sodium hydroxide) having a concentration of 44.5+/−2, diluted with water, at a temperature of 132 degrees C.+/−2 degrees. The downwardly extending end of the fiber is dipped into the tipping solution for about 17 min+/−1 min. The length of the tip which is dipped into solution is 5 mm.sup.˜6 mm+/−1 mm. The final tip length is approximately 1 mm+/−0.2 mm. Said another way, the solution removes approximately 4 mm and 1 mm is left. This is the ZZ dimension in FIG. 7.

[0150] The Tipping Process as Applied to Triangular Bristles

[0151] As noted above NaOH is a solution used to dip the tips of the round bristles into to eat away at the tips which gives the fiber a softer feel on the face.

[0152] For the triangular bristles, its a little different.

[0153] A normal PBT fiber bundle (with circular cross sections) is dense, while the triangular fiber bundle is less dense, due to the shape of the fiber.

[0154] With less density, the fibers more easily soak with and absorb the NaOH solution. So there is a need to better control the process to avoid the triangular fiber bundle absorbing too much NaOH solution. This is done by soaking the material in water before it is “tipped”.

[0155] The bundle is soaked in water for 10 minutes at room temperature. Otherwise the tipping process for the round bristles is used.

[0156] Quadrangular Bristles

[0157] In other example aspects, the bristles 20 can be quadrangular bristles 22, wherein each quadrangular bristle 22 defines a quadrangular transverse cross section. A quadrangle can be defined as a four-sided plane figure. FIGS. 8A and 8B illustrate a first example of a quadrangular bristle 22 (aka a quadrangular fiber 22) defining a substantially rectangular transverse cross-section. In example aspects, the rectangular transverse cross-section can be that of a square, as shown in FIG. 8B. It should be understood that a square is a rectangle defining four straight sides 802 of equal length and four interior angles 804 of equal dimension. In example aspects, each of the sides 802 can define a length L.sub.1 between about 0.03 mm and 0.08 mm, and more specifically between about 0.04 mm and 0.06 mm. In another more specific aspect, the length L.sub.1 of each side can be about 0.05 mm. As such, the diagonal D.sub.1 of the square can be between about 0.04 mm and 0.11 mm, and more specifically, between about 0.06 mm and 0.09 mm. In a more specific aspect, the diagonal D.sub.1 can be about 0.07 mm. The interior angles 804 of the square can add up to about 360°, and each angle can be about 90°. Furthermore, as shown in FIG. 8A, the quadrangular bristles 22 can define four substantially parallel edges 806 extending along a length of the quadrangular bristle 22, as illustrated, from a restrained end 808 to a free end 1110. The restrained end 808 and free end 1110 are further described below.

[0158] FIG. 8C illustrates another aspect of the brush assembly 10, according to the present disclosure. The brush assembly 10 can be, for example, a cosmetics brush 1150. The cosmetics brush 1150 can comprise a bundle of the quadrangular bristles 22 coupled to the ferrule 30. In example aspects, the ferrule 30 can be coupled to the handle 40. As shown, each of the quadrangular bristles 22 can define the restrained end 808 attached to the ferrule 30 and the free end 1110 distal from the ferrule 30. In some aspects, the quadrangular bristles 22 can define a short tip at the free end 1110. The process for forming a short tip is explained in further detail below. According to example aspects, cosmetics can be applied to the free ends 1110 of the quadrangular bristles 22.

[0159] FIGS. 9A and 9B illustrate another example aspect of a quadrangular bristle 22, also defining a quadrangular transverse cross section. As shown in FIG. 9B, the quadrangular transverse cross section of the quadrangular bristle 22 of the current aspect can define four concave sides 902 and four interior angles 904. In example aspects, a diagonal D.sub.2 of the quadrangle can be between about 0.04 mm and 0.11 mm, and more specifically, between about 0.06 mm and 0.07 mm. In a more specific aspect, the diagonal D.sub.2 can be about 0.07 mm. In example aspects, as shown, the each of the four concave sides 902 can be of equal length, and each of the angles 904 of the quadrangle can be less than 90°. Each angle 904 can also be equal to each other. As shown in FIG. 9A, the quadrangular bristle 22 can further define four substantially parallel edges 906 extending along a length of the quadrangular bristle 22.

[0160] Each of the quadrangular bristles 22 of FIGS. 9A and 9B can define a restrained end 908 that can be attached to the ferrule 30 (shown in FIG. 8C) and a free end 1210 opposite the restrained end 908. Some aspects of the quadrangular bristles 22 can also define a short tip at the free end 1210.

[0161] Still other aspects of the quadrangular bristles 22 can define a quadrangular transverse cross section of another shape. For example, other aspects of the quadrangular transverse cross section can define a diamond, kite, rhombus, trapezoid, a quadrangle with convex sides, a quadrangle with sides of varying length, or any other suitable quadrangular shape. Referring generally to all aspects of the quadrangular bristles 22, some example aspects of the cosmetic brush 1150 (shown in FIG. 8) can intermix the quadrangular bristles 22 with rounded bristles (not shown) defining a circular or rounded transverse cross section. In such an aspect, the quadrangular bristles 22 can be referred to as primary bristles or fibers, and the rounded bristles can be referred to as secondary bristles or fibers. Also referring generally to all aspects of the quadrangular bristles 22, some or all of the quadrangular bristles 22 can define a wave pattern formed by a crimping process during manufacturing.

[0162] The Extrusion Process as Applied to Quadrangular Bristles

[0163] Similar to a bundle of the triangular bristles 21 described above, the quadrangular bristles 22 can be manufactured by extruding the PBT material through an extrusion plate 100. In other aspects, the quadrangular bristles 22 can be formed from another material, such as, for example polybutylene terephthalate, polyethylene terephthalate (PET), nylon, Sorona®, and Natrafil®, as mentioned above. FIG. 10 illustrates another example aspect of the extrusion plate 100. As shown, the extrusion plate 100 can define a plurality of the extrusion holes 102, and each of the extrusion holes 102 can define a quadrangular shape. In example aspects, such as the depicted aspect, the quadrangular shape of each of the extrusion holes 102 can define concave sides of equal length, such that the extrusion plate 100 can form the quadrangular bristles 22 shown in FIGS. 9A and 9B. In other aspects, as shown in FIG. 10, the quadrangular shape of each extrusion hole 102 can define a square, such that the extrusion plate 100 can form the quadrangular bristles 22 shown in FIGS. 8A and 8B. In still other aspects, the extrusion holes 102 can define a different quadrangle shape, such as, for example, a quadrangle with convex sides, a quadrangle with sides of varying lengths, etc.

[0164] The Tipping Process as Applied to Quadrangular Bristles

[0165] The tipping process can involve dipping the free ends 1110, 1210 of the quadrangular bristles 22 in a chemical solution that can eat away at the quadrangular bristles 22 to create a more pointed free end 1110, 1210. For example, the chemical solution can be a sodium hydroxide (NaOH) solution. In some aspects, to prevent the bundle of quadrangular bristles 22 from absorbing too much of the NaOH solution, the bundle of quadrangular bristles 22 can be soaked in water before performing the tipping process. In example aspects, the bundle of quadrangular bristles 22 can be soaked in room-temperature water for about 10 minutes. In other aspects, the bundle of quadrangular bristles 22 can be soaked in water that is warmer or cooler than room temperature and/or can be soaked for more or less than 10 minutes. In still other aspects, the bundle of quadrangular bristles 22 may not be soaked in the water before performing the tipping process.

[0166] Bristles with Star-Shaped Cross-Section

[0167] In other example aspects, the bristles 20 can be star prism bristles or fibers, wherein each star prism bristle or fiber can define a star-shaped transverse cross section. A star can be defined as a plane figure having five corner vertices and ten sides. FIG. 11 illustrates a first example of a star prism bristle 1122 defining a substantially star-shaped transverse cross-section 1125. The star-shaped transverse cross section 1125 of the star prism bristle 1122 can define five corner vertices 1130 and ten sides 1140. In example aspects, the star-shaped transverse cross-section 1125 can be that of a pentagram, as shown. As such, in some aspects, each of the star prism bristles 1122 can be a pentagrammic prism bristle 1123. It should be understood that a pentagram is a star defining ten straight sides 1140 of equal length and five interior vertex angles θ of equal dimension. In example aspects, each of the sides 1140 can define a length L.sub.3 between about 0.015 mm and 0.040 mm. For example, in a particular aspect, the length L.sub.3 can be about 0.018 mm. In another aspect, the length L.sub.3 can be about 0.025 mm. In another aspect, the length L.sub.3 can be about 0.036 mm. In still other aspects, the length L.sub.3 can be greater or smaller than the stated range. Furthermore, according to example aspects, each of the interior vertex angles θ can be formed at a corresponding one of the corner vertices 1130 and can be about 36°. In other aspects, however, the sides 1140 of each star prism bristle 1122 may define varying lengths and/or varying interior vertex angles θ.

[0168] As shown in FIG. 11, each of the star prism bristles 1122 can define five substantially parallel outer edges 1150 extending along a length L.sub.2 of the star prism bristle 1122 and five substantially parallel inner edges 1155 extending along the length L.sub.2 of the star prism bristle 1122. Each of the inner edges 1155 can be positioned generally between and inward of a corresponding pair of the outer edges 1150, relative to a center axis 1110 extending through a center of the star prism bristle 1122. A bristle wall 1160 can be formed between each adjacent pair of outer and inner edges 1150, 1155 and can extend from a first end 1170 of the star prism bristle 1122 to a second end 1180 of the star prism bristle 1122, as shown. As such, a pair of adjacent bristle walls 1160a,b can be formed between each adjacent pair of outer edges 1150. Each of the bristle walls 1160 can be angled inward relative to the center axis 1110, such that each of the pairs of adjacent bristle walls 1160a,b can meet at a corresponding one of the inner edges 1155 and can define an elongated indentation 1190 therebetween. The elongated indentation 1190 can extend along the length L.sub.2 of the star prism bristle 1122, as shown. According to example aspects, each of the elongated indentations 1190 can define a substantially triangular prism shape overall and a substantially triangular cross sectional shape. In some aspects, each of the bristle walls 1160 can be substantially planar, while in other aspects, each of the bristle walls 1160 may not be substantially planar. Each of the outer edges 1150 and inner edges 1155 can be configured to extend from the first end 1170 of the star prism bristle 1122 to the second end 1180 of the star prism bristle 1122, as shown. In some aspects, the first end 1170 of the bristle 1122 can be a free end 1175 and the second end 1180 of the bristle 1122 can be a restrained end 1185, as described in further detail below.

[0169] Referring to FIG. 12, according to example aspects, a plurality of the star prism bristles 1122 can grouped together form a bundle 1210. In some aspects, the bundle 1210 of star prism bristles 1122 can be couple to the ferrule 30 (shown in FIG. 1). The bundle 1210 of bristles 1122 and the ferrule can define the brush assembly 10 (shown in FIG. 1), which can be, for example, a cosmetics brush. In example aspects, the brush assembly 10 can further comprise the handle 40 (shown in FIG. 1) coupled to the ferrule 30. Each of the star prism bristles 1122 can define the restrained end 1185 (shown in FIG. 11) attached to the ferrule 30 and the free ends 1175 thereof can be distal to the ferrule 30. In some aspects, each of the star prism bristles 1122 can define a short tip 1220 at the free end 1175 thereof. The process for forming a short tip 1220 is explained in further detail below. According to example aspects, cosmetics can be applied to the free ends 1175 of the star prism bristles 1122.

[0170] Other aspects of the star prism bristles 1122 can define a star-shaped transverse cross section 1125 having a shape other than pentagonal. For example and without limitation, other aspects of the star-shaped transverse cross section 1125 can define a hexagram, heptagram, octagram, three-pointed star, four-pointed star, or any other suitable star shape. Referring generally to all aspects of the star prism bristles 1122, some example aspects of the bundle 1210 can intermix the star prism bristles 1122 with the triangular bristles 21 (shown in FIG. 2), rounded bristles (not shown) defining a circular or rounded transverse cross section, the quadrangular bristles 22 (shown in FIG. 8A) defining a rectangular transverse cross section, and/or bristles defining any other suitable transverse cross-sectional shape. In such an aspect, the star prism bristles 1122 can be referred to as primary bristles or fibers, and the bristles defining another transverse cross-sectional shape can be referred to as secondary bristles or fibers, tertiary bristles or fibers, and so on. For example, in an aspect of the brush assembly 10 comprising the star prism bristles 1122, the triangular bristles 21, and quadrangular bristles 22, the star prism bristles 1122 can be referred to as primary bristles, the triangular bristles 21 can be referred to as secondary bristles, and the quadrangular bristles 22 can be referred to as tertiary bristles. Also referring generally to all aspects of the star prism bristles 1122, some or all of the star prism bristles 1122 in the bundle 1210 can define a wave pattern formed by a crimping process during manufacturing. In aspects of the bundle 1210 also comprising bristles having another transverse cross-sectional shape, some or all of those bristles may also define a wave pattern formed by a crimping process during manufacturing.

[0171] The Extrusion Process as Applied to Star Prism Bristles

[0172] Similar to a bundle of the triangular bristles 21 described above, the bundle 1210 of star prism bristles 1122 can be manufactured by extruding the PBT material through the extrusion plate 100 (shown in FIG. 3). In other aspects, the star prism bristles 1122 can be formed from another material, such as, for example polybutylene terephthalate, polyethylene terephthalate (PET), nylon, Sorona®, and Natrafil®, as mentioned above. According to example aspects, the extrusion plate 100 can define a plurality of the extrusion holes 102 (shown in FIG. 5), and each of the extrusion holes 102 can define a star shape. For example, in a particular example aspect, each of the extrusion holes 102 can define a pentagram shape to form the illustrated pentagrammic prism bristles 1123. In other aspects, the extrusion holes 102 can define any other suitable star shape, such as a three- or four-pointed star, a hexagram, a heptagram, an octagram, or the like.

[0173] The Tipping Process as Applied to Star Prism Bristles

[0174] The tipping process can involve dipping the free ends 1175 of the star prism bristles 1122 in a chemical solution that can eat away at the bristles 1122 to create more pointed free ends 1175 thereof, resulting in the short tips 1220. For example, the chemical solution can be a sodium hydroxide (NaOH) solution. In some aspects, to prevent the bundle 1210 of star prism bristles 1122 from absorbing too much of the NaOH solution, the bundle 1210 of star prism bristles 1122 can be soaked in water before performing the tipping process. In example aspects, the bundle 1210 of star prism bristles 1122 can be soaked in room-temperature water for about 10 minutes. In other aspects, the bundle 1210 of star prism bristles 1122 can be soaked in water that is warmer or cooler than room temperature and/or can be soaked for more or less than 10 minutes. In still other aspects, the bundle 1210 of star prism bristles 1122 may not be soaked in the water before performing the tipping process.

[0175] Conclusion

[0176] Various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

[0177] One should note that conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more particular embodiments or that one or more particular embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. It should be emphasized that the above-described embodiments are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the present disclosure. Any process descriptions or blocks in flow diagrams should be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process, and alternate implementations are included in which functions may not be included or executed at all, may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the present disclosure. Further, the scope of the present disclosure is intended to cover any and all combinations and sub-combinations of all elements, features, and aspects discussed above. All such modifications and variations are intended to be included herein within the scope of the present disclosure, and all possible claims to individual aspects or combinations of elements or steps are intended to be supported by the present disclosure.