Patent Application
20150020332
The invention is in the field of molded cosmetic applicators, especially for delivering a high volume of product to the eyelashes, and for grooming the eyelashes and eyebrows.
Mascara brushes having a molded rod (core) and/or bristles are known. The rod and bristles may be integrally molded simultaneously, in one molding cycle, or parts of the applicator may be formed in successive molding cycles. Being able to form a complete applicator in one molding cycle is a significant advantage in time and cost.
It is common for the molded bristles or tines to taper down toward the free end of the bristle. One example of this is a conical bristle, although other tapered shapes have been used (see for example US2006-0070635). Molded bristles in various other shapes are also known (i.e. U.S. Pat. No. 7,503,093; U.S. Pat. No. 7,992,577; U.S. Pat. No. 8,336,560; US2012-0170965; US2012-0192892). It is also known to form the bristles with one or more depressions, protrusions or other features that are, in some way, intended to affect the performance of the brush (i.e. U.S. Pat. No. 7,503,093 especially
None of the foregoing discloses a molded cosmetic applicator having semi-conical bristles with at least two depressions and/or protrusions located only on the curved surface of the semi-cone, wherein the bristles and applicator core are integrally molded in one molding cycle.
A main object of the invention is to provide a molded cosmetic applicator having semi-conical bristles with at least two depressions and/or protrusions located only on the curved surface of the semi-cone.
Another main object of the invention is to provide a method of making the foregoing applicator wherein the bristles and applicator core are integrally molded in one molding cycle.
We disclose a molded cosmetic applicator head having a core that supports an array of semi-conical bristles arranged in rows and columns, such that the surfaces of the bristles assume certain orientations, and wherein at least some of the bristles have at one or more depressions and/or protrusions located on a curved surface. The bristles and applicator core are integrally molded in one injection molding cycle. Protrusions along the height of the bristles provide improved separation of hairs and better definition. Depressions along the height of the bristles act as reservoirs of product, so that the present invention delivers more product than a conventional applicator head. This applicator head can be used for eyelash makeup and treatment products, as well as eyebrow makeup and treatment products.
a is a perspective view of one embodiment of an applicator head having semi-conical bristles comprising multiple depressions on the rounded surface and no surface features on the flat surface.
c shows one of the bristles.
a is a perspective view of one embodiment of an applicator head having semi-conical bristles comprising multiple depressions on the rounded surface and no surface features on the flat surface.
a and 12b show another embodiment of the semi-conical bristles with multiple protrusions (P) and multiple depressions (D).
a-d show several dimensions of some preferred embodiments of the bristles.
a-b show an applicator head (10) with 5 columns of bristles symmetrically arranged, and its assembly to a handle.
Throughout the specification, the word “comprise” (or its conjugates) means that a collection of objects is not necessarily limited to those objects explicitly recited.
By “cone” we mean a right circular cone.
Strictly speaking, the terms “semi-cone” and “semi-conical” include a cone whose base is a semi-circle (i.e. the arc of the base measures 180°). For convenience, however, “semi-cone” and “semi-conical” will also include a cone whose base is a circular segment having an arc of about 160° to no more than 180°.
Throughout the specification, the “proximal end” of the applicator head is the end nearer to a handle, as described below. The “distal end” of the applicator head is the end farther from the handle.
Mascara applicators typically comprise a handle, a rod or core extending from the handle, and an array of bristles projecting from the core. The present invention contemplates specific bristle shapes integrally molded with the core, in one molding cycle. The molded core and bristles may be referred to as the applicator head. The handle may also be integrally molded with the applicator head, or the applicator head may be attached to a handle at a later time.
A mold (2) according to the present invention, comprises a number of mold sections (2a), that when assembled, form the mold cavity (1). Each mold section has a sculpted lateral face (2b) and a flat lateral face (2c). The sculpted lateral face is flat except for bristle spaces (1b) cut into it. Each bristle space opens up onto the sculpted lateral face. In contrast, the flat lateral face is continuously flat, and has no bristle spaces therein.
Generally, one or more sections (2a) of the mold (2) may differ from one or more other sections of the mold. However, in the more preferred embodiments of the invention, the multiple sections of the mold are substantially identical, so that a molded applicator head has cylindrical symmetry along its length. Preferably, each mold section (2a) is shaped as a truncated solid circular sector (as in
The sculpted lateral face (2b) and flat lateral face (2c) have a relative orientation defined by a central angle, y. For example, in
In an assembled mold, the interior faces (2d) define the core space (1a) and the shape of the core (10a) of the molded article. (Note: In
The more sections (2a) in a mold, the more flexibility there is in designing cosmetic applicators of the present invention. However, increasing the number of mold sections makes the mold more difficult to operate in a commercial manufacturing environment. Therefore, in preferred embodiments, M=2−12. Molds with 5, 6, 10 or 11 sections (i.e. γ=72°, 60°, 36° or 32.72°, respectively) are more preferred. Molds with 7 sections (γ=51.43°) or 9 sections (γ=40°) are still more preferred, and exactly 8 sections (γ=45°)is most preferred. Of course, when there are relatively fewer columns of bristles (i.e. 4, 3 or 2; γ=90°, 120°, 180°), then the applicator performs more like a comb and less like a brush, but this is still within the scope of the present invention.
In preferred embodiments, bristle spaces (1b) are regularly arranged in columns that extend down the core space (1a), parallel to the longitudinal axis of the core space. In an assembled mold, a column of bristle spaces is defined by adjacent mold sections (2a) that contact each other. The number of columns in a mold equals the number of mold sections, M. This is because each mold section has one column of bristle spaces cut into its sculpted lateral face (2b, see
In preferred embodiments, bristle spaces (1b) are regularly arranged in rows, each row lying on a circumference of the core space (1a), in a plane that is perpendicular to the longitudinal axis of the core space. It may be appreciated that the maximum number of bristle spaces in a row is equal the number of mold sections, M. This is because each mold section may contribute only one bristle space or no bristle spaces to each row. In some preferred embodiments, all rows have M bristle spaces that are evenly spaced around a circumference of the core space.
In the most preferred embodiments, bristle spaces are regularly arranged in columns and rows. The bristle spaces of the mold typically extend radially from the core space, so that in a molded applicator head, the bristles (10b) extend radially from the core (10a) of the applicator head. In terms of releasing the finished part from the mold without damaging the bristles, A row and column arrangement of radial bristle spaces is most preferred, but may not be absolutely necessary in every embodiment.
As noted above, each mold section has a sculpted lateral face (2b) and a flat lateral face (2c). In the assembled mold, a bristle space is defined by the sculpted lateral face of one mold section contacting the flat lateral face of an adjacent mold section. Thus, every bristle space in the mold has at least one flat face (1c) that extends the length of the bristle space. This flat face is free of features, such as prominent protrusions and prominent depressions, and is a characterizing feature of the bristle spaces of a mold according to the present invention.
The other sides of the bristle spaces (1b) may comprise flat and/or rounded portions, and the horizontal cross section of the bristle space could be any conceivable shape, only limited by the ability to machine the mold section. Preferred, however, is a bristle space having a horizontal cross section that is shaped as a circular segment that has an arc that ranges from about 160° to no more than 180°, and whose radius decreases as you move from base to tip. Such a bristle space would have a semi-conical profile comprised of a flat face (1c) and a curved face (1d). Preferably, the bristle space would have a rounded tip (1e, see
An applicator head (10) comprises core (10a) and an array of bristles (10b) projecting from the core. The present invention contemplates specific bristle shapes integrally molded with the core, in one molding cycle.
The core (10a) of the applicator head is integrally molded with the bristles (10b). The core may be of solid material or it may have a hollowed interior portion. A hollowed interior portion would require an additional die in the molding operation. Preferably, the core has a circular cross section. In some embodiments, the core is approximately cylindrical. Alternatively, the core may have wider and narrower portions. For example, in the figures, the core is wider in the middle and tapers toward either end.
In some embodiments (see
Each bristle space (1b) in the mold (2) will give rise to one bristle (10b) in a molded applicator head (10). Thus, the number of bristles in a finished applicator head is equal to the number of bristles spaces in the mold. As noted above, every bristle space (1b) in the mold has a flat face (1c) that extends the length of the bristle space. Consequently, every bristle in a molded applicator head will have a flat surface (10c) that extends the full height, H, of the bristle, and that is free of surface features such as protrusions and depressions (see
A bristle molded in a bristle space according to the preferred embodiment described above, is semi-conical, comprising a flat surface (10c), a curved surface (10d), and a rounded tip (10e). Each bristle would also have one or more prominent surface features on its curved surface. Prominent surface features may include depressions, protrusions, or any combination thereof. A prominent depression on the curved face (1d) of the bristle space (1b) gives rise to a prominent protrusion on the curved surface (10d) of the bristle. Likewise, a prominent protrusion on the curved face of the bristle space gives rise to a prominent depression on the curved surface of the bristle. Preferably, each semi-conical bristle has at least two prominent depressions and/or prominent protrusions located on its curved surface. More preferably, in an applicator head, at least some of the bristles have from 4 to 8 prominent depressions and/or prominent protrusions. Even more preferably, in an applicator head, at least some of the bristles have from 9 to 12 prominent depressions and/or prominent protrusions.
In contrast, the flat surface (10c) of the bristle (10b) has no prominent depressions or prominent protrusions. Referring to
Within the limits herein described, the semi-conical bristles (10b) in an applicator head (10) may have any size and spacing suitable for its intended functions, e.g., application, arrangement, and/or separation of human hairs, such as eyelashes. Also, all the bristles in a single applicator head may be same or different. For example, all the bristles in a single applicator head may be same height, H, or not.
The prominent protrusions and/or prominent depressions of the bristles may be any suitable size or shape. From one bristle to the next, the sizes and shapes of the protrusions and/or depressions may be the same or different, and they may be located at the same height along each bristle or not. On any given bristle, the protrusions and/or depressions may be symmetrically located or not. In some preferred embodiments, a prominent depression is concavity below the curved surface (10d) of a bristle that has a depth between 0.1 mm and 1.2 mm, more preferably from about 0.2 mm to about 0.8 mm, and most preferably from about 0.3 mm to about 0.6 mm; and a width (i.e. largest lateral dimension) of 0.01 mm to 0.15 mm, more preferably from about 0.05 mm to about 0.12 mm, and most preferably from about 0.08 mm to about 0.10 mm. In some preferred embodiments, a prominent protrusion is convexity above the curved surface of a bristle that has a height between 0.1 mm and 1.2 mm, more preferably from about 0.2 mm to about 0.8 mm, and most preferably from about 0.3 mm to about 0.6 mm; and a width (i.e. largest lateral dimension) of 0.01 mm to 0.3 mm, more preferably from about 0.05mm to about 0.15 mm, and most preferably from about 0.08 mm to about 0.7 mm. Thus, a “prominent depression” or “prominent protrusion” includes intentional surface features that result from machining the bristle space (1b), but does not include random, microscopic irregularities in the surface of the bristle material.
Several embodiments of bristle types according to the present invention are shown in the figures. These will be described in comparison to a semi-conical bristle that has no prominent surface features. Throughout the drawings, prominent depressions will be denoted by D, and prominent protrusions by P.
a-c: The bristles (10b) nearer the ends of the core (10a) have four completely formed prominent depressions (two on a first side of the bristle, and two on a second side of the bristle). Toward the middle of the core, the bristles have six completely formed prominent depressions, three on each side. In between, some bristles have four completely formed prominent depressions and two partially formed depressions, because the height of these bristles was able to accommodate such. A mold section (2a) that might be used to create the applicator head of
a-7c: The bristles (10b) nearer the ends of the core (10a) have six completely formed depressions (three on a first side of the bristle, and three on a second side of the bristle). Toward the middle of the core, the bristles have ten completely formed depressions, five on each side. In between, some bristles have a mix of completely formed depressions and partially formed depressions.
a and 11b: Each semi-conical bristle (10b) has three depressions (D), and six protrusions (P) on the rounded surface (10d).
a and 12b: Each semi-conical bristle (10b) has four depressions (D), nine protrusions (P1) of one type, and three protrusions (P2) of a second type, all on the rounded surface (10d).
In all cases, the protrusions and/or depressions are located on the rounded surface (10d) of an otherwise semi-conical bristle. In every embodiment, the flat surface (10c) is free of any prominent surface features. This is characteristic of the present invention.
b shows an applicator head (10) with 5 columns of bristles symmetrically arranged.
Referring to
Angle W ranges from 0° to about 20°, preferably 5° to 15°, more preferably 5° to 10°. When W=0°, the bristle has an exactly semi-circular cross section. A value of 0<W≦20° means that the cross section is a circular segment having an arc of about 160° to 180°, which may make release from the mold somewhat easier.
Angle X, the base angle of the semi-cone, is about 1° to about 15°, preferably, 2° to 10°, more preferably 3° to 5°.
Y, the width of the base of a bristle, measured across the flat surface (10c) of the bristle, is about 0.1 mm to abut 2 mm, preferably 0.2 mm to 1.5 mm, more preferably 0.3 mm to 0.9 mm.
Angle Z is about 3° to about 12°, preferably 3° to 8°, more preferably 3° to 5°. H, the height of the bristles will range from about 0.1 mm to about 10 mm, preferably from 0.5 mm to 7 mm, and more preferably from 0.8 mm to 5 mm.
Exemplary materials that can be used in the present invention to mold cosmetic applicator heads include, but are not limited to: silicone elastomers, thermoplastic elastomers (such as, for example, styrene-ethylene-butylene-styrene block copolymer—SEBS), vinyl elastomers (EVA), thermoplastic polyester elastomers (Hytrel® from Dupont de Nemours), thermoplastic polyurethane elastomers (pellethane® from Dow Plastic), Nitrile, and EPDM. Hardness of the chosen material preferably ranges from about 35 MPa (35 shore D Hytrel® from Dupont de Nemours) to about 1180 MPa (82 shore D Hytrel®). More preferably the tensile modulus ranges from about 95 MPa (45 shore D Hytrel®) to about 570 MPa (72 shore D Hytrel®). Most preferably, tensile modulus ranges from about 200 MPa (55 shore D Hytrel®) to about 280 MPa (63 shore D Hytrel®).
Applicator heads as described herein, are preferably made by injection molding. When a set of mold sections (2a) are assembled, a mold cavity (1) is defined. Access into the mold cavity is through an opened end of the core space (1a). Molten material may be injected into the mold cavity through the opened end. When a molded applicator head is to be released from the assembled mold (2), the flat faces (2c) of the mold sections (2a) are made to move away from each other radially, and parallel to the flat faces (10c) of the bristles (10b). This is most easily seen in
