US20230165363A1

US20230165363A1 - Cosmetic applicator for applying a cosmetic composition to keratinous fibers such as eyelashes or eyebrows

Info

Publication number: US20230165363A1
Application number: US17/995,433
Authority: US
Inventors: Alexis LEONARD
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2020-04-06
Filing date: 2021-04-01
Publication date: 2023-06-01
Also published as: KR20220149723A; EP4132323A1; CN115334938A; WO2021204659A1

Abstract

A cosmetic applicator (3) for applying a composition (P) to human keratinous fibers, notably eyelashes or eyebrows, is provided. The cosmetic applicator (3) comprises: —A stem (5) having at least a rectilinear portion extending along a rectilinear axis (Y), —a brush (10) at one end of the stem (5), the brush comprising: —a curved core (43) having a distal end (46) and defining a convex side and an opposite concave side, the distal end of the core being offset from the rectilinear axis (Y) of the stem on the convex side of the core, —application members (41) supported by the core (43).

Description

FIELD OF THE INVENTION

The present invention relates to brushes for applying a cosmetic composition to the eyelashes or eyebrows, notably a makeup or care product, for example mascara, and to packaging and application devices comprising such a brush.

PRIOR ART AND OBJECTIVES OF THE INVENTION

Mascara applicators, in which the brush comprises a core formed by two arms of a metal wire that are twisted together and grip bristles, are known. Since the bristles used are generally of the same length, once the arms are twisted, the brush has an envelope surface in the form of a cylinder of revolution. Such a shape has limited effectiveness in terms of loading the eyelashes with product and in terms of separation.
Efforts have thus been made to give the envelope surface more complex shapes so as to form on the brush, after wiping, zones that are more heavily laden with product, making it possible to properly load the eyelashes, and zones that are less heavily laden or are laden little, these being usable to comb and separate the eyelashes. Finding the shape that results in the optimum makeup result requires numerous tests, since many factors are involved.
Similar issues arise with brushes made by injection molding.
EP1236419 discloses brushes with a curved core and a distal end of the core offset from the longitudinal axis of the stem, on the concave side of the core.
There is a need to make it easier to apply makeup along the upper and lower rows of the eyelashes.
There is also a need to improve brushes, notably to benefit from brushes that are capable of satisfactorily making up the eyelashes or eyebrows, by providing a satisfactory load of product and good combing ability.
Applicator
The present invention, according to one of its aspects, relates to an applicator for applying a cosmetic composition to human keratinous fibers, notably eyelashes or eyebrows, comprising:

- A stem having at least a rectilinear portion extending along a rectilinear axis,
- a brush at one end of the stem, the brush comprising:
  - a curved core having a distal end and defining a convex side and an opposite concave side, the distal end of the core being offset from the rectilinear axis of the stem on the convex side of the core,
  - application members supported by the core.
    “Convex” means convex toward the outside. By “the distal end of the core being offset from the rectilinear axis of the stem on the convex side of the core” it is meant that the vector GD defined by the orthogonal projection G of the distal end of the core onto the rectilinear axis of the stem and the distal end D of the core and oriented from G to D has a substantially same orientation as a vector H perpendicular to the rectilinear axis of the stem and oriented from the concave side of the longitudinal axis of the core toward the convex side. In other words, if one has to tilt the core from an initial configuration where the distal end would be aligned with the rectilinear longitudinal axis of the stem to a final configuration having the desired offset, the tilting would be carried out by deforming the core in a direction going from the intrados of the core toward the extrados of the core.
    Thanks to the invention, the performance of the brush in terms of loading the lashes with product while providing satisfactory combing is increased. By virtue of the invention, a brush is available that offers a reserve of product, in the concave portion, and a combing zone, less heavily laden with product, in the convex portion. Due to the offset, there can be more interference between the wiper member and the brush, leading to less composition left on the convex side of the brush near the distal end thereof. This increased interference may allow to use more viscous compositions, with increased make-up performance. The invention may make it easier to apply the composition, and to avoid formation of clumps during application. The invention makes it also easier to make up lashes in the corner of the eye.
    Preferably, the stem is rectilinear along its entire length. This enables to use a conventional straight stem for the applicator, easy to manufacture and assemble with the brush. In some variants, however, the stem has a main rectilinear portion, that extends preferably over most of its length, and a distal portion that makes an angle with the rectilinear portion of the stem, the orientation of the distal portion of the stem providing, or at least contributing to some extent, to the desired offset for the distal end of the core.
    Preferably, the core is a twisted wire core, but the invention also applies to injection molded brushes. In case the core is a twisted wire core, the application members are bristles held between the turns of the strands of the core that are twisted together, as is conventional.
    Preferably, the core is non rectilinear over its entire length from the stem to its distal end. However, in some variant embodiments, the core may have at least one segment that is rectilinear, while keeping an overall curved shape. Preferably, the curved core is of constant curvature, but the core may have a radius of curvature that varies along the bristle carrying portion.
    The distance from the rectilinear axis of the stem to the curved core may reach a maximum at some position between the proximal and distal ends of the curved core, preferably at some position between one quarter and three quarters of the length of the curved core between these proximal and distal ends, more preferably between one third and two thirds of said length.
    Preferably, the core extends along a longitudinal axis of substantially constant radius of curvature from the stem to the distal end of the core. Such a radius of curvature may be greater or equal to 34 mm and less or equal to 47 mm, being preferably of about 40 mm
    Preferably, the longitudinal axis of the core extends in a plane. Such a plane is preferably a midplane plane of symmetry for the envelope surface of the brush defined by the free ends of the application members.
    Preferably, the application members define an envelope surface of non-circular cross section along at least part of its length. The application members can be bristles or spikes that extend around the core.
    The envelope surface may define at least one facet of flat cross section on the convex side of the core, i.e. on the extrados of the brush. In some variants, the envelope surface defines at least one facet of recessed cross section on the convex side of the core. Such a recessed cross section may form at least one longitudinal groove extending along the brush on the convex side of the core, i.e. on the extrados of the brush.
    In some embodiments, the cross section of the surface envelope of the brush has a plurality of rectilinear segments connected by circular arcs. The angular extension of the circular arcs around the core may be relatively small, giving the cross section of the brush a substantially triangular shape.
    The cross section of the surface envelope may be of substantially triangular contour, with an apex situated in the plane along which the longitudinal axis of the core extends.
    The tilt angle between the rectilinear axis of the rectilinear portion of the stem and a straight line connecting the distal end of the core to the distal end of the rectilinear portion of the stem preferably ranges from 0.5 to 10°, better 0.6 to 8°, more preferably from 0.7° to 5.7° and most preferably from 2° to 4.5°, being for example of about 3.2°.
    Preferably, the offset is greater than 0.5 mm. Preferably the offset is no greater than 2.5 mm. It is advantageous that the offset remains small enough to allow the introduction of the brush in a container containing the composition to be applied and provided with a wiper member defining a wiping orifice, without the distal end of the core abutting against the wiper member, with an introduction movement of the brush being a linear displacement along the rectilinear axis of the stem. This enables an automated mounting of the applicator on the container with a simple mechanism. The offset may not be greater than half the diameter of the wiping orifice, and preferably is close to it. The offset f may range from 0.8D/2 to 1.2D/2, better from 0.9D/2 to 1.1D/2, even better from 0.8D/2 to D/2 or more preferably from 0.9D/2 to D/2, if D is the diameter of the wiping orifice.

The envelope surface may comprise a frustoconical or ogee-shaped distal portion with a cross section that becomes smaller toward the distal end of the core. The frustoconical or ogee-shaped distal portion may extend over a length greater than one quarter of the length L of the portion of the core bearing the application members, and less than one third of the length L of the portion of the core bearing the bristles.
At its opposite end from the brush, the stem may be fastened to a cap for closing a container.
Device
According to another of its aspects, in combination with the above, the invention further relates to a device for applying a cosmetic composition on keratinous fibers, preferably eyelashes, comprising:

- A container containing said composition, comprising a wiper member and,
- an applicator according to the invention, as defined above.
  The wiping member is configured for removing the excess product present on the stem and on the brush. This wiping member comprises, for example, a lip made of an elastomer material, defining a wiping orifice which preferably has a circular cross section, the diameter of which corresponds substantially to that of the stem.
  The wiper member and the brush may be configured so that when the applicator is withdrawn from the container along said rectilinear axis, application members situated on the convex side of the core, i.e. on the extrados of the brush, at an axial position less than 3 mm from the proximal end of the brush, measured along the curved longitudinal axis of the core, contact the wiper member. In some embodiments, the smaller this distance, the better it is, as this means that the extrados of the brush contacts the wiper member at an earlier stage of the passage of the brush through the wiper member, resulting in the absence of clump of composition near the proximal end of the brush on the extrados thereof.

Method for Manufacturing a Brush
According to another of its aspects, in combination with the above, the present invention further relates to a method for manufacturing a brush for use in an applicator as defined above, comprising:

- Machining a twisted wire core brush with a rectilinear core to form at least one planar or recessed facet of an envelope surface defined by the free ends of the bristles, the core having a proximal portion for fixing into a stem and a bristle carrying portion,
- deforming the core to impart to the bristle carrying portion a curved shape with a convex side and a concave side, the distal end of the core being offset from the longitudinal axis of the proximal portion of the core on the convex side.
  The core may be deformed along a plane of curvature.
  The planar or recessed facet preferably lies on the extrados of the brush after curvature of the core.
  The machining may comprise forming at least one planar facet or at least one facet with a recess of the envelope surface, along the longitudinal direction of the brush, over most of its length.
  The machining may comprise forming three planar facets of the envelope surface, giving the envelope surface a substantially triangular shape in cross section, an apex lying in the plane of curvature of the core.
  The machining may comprise forming a frustoconical head.
  The one or more facets may be machined so that they intersect the frustoconical head.
  The deforming of the core may comprise imparting the bristle carrying portion a constant curvature then tilting the core at the junction of the bristle carrying portion with the proximal portion, or vice versa.
  According to another of its aspects, the present invention further relates to a method for manufacturing a brush for use in an applicator as defined above, comprising injection molding the core and the application members in at least one plastics material.

Makeup Method
A further aspect of the invention is a makeup method for making up human keratinous fibers, comprising applying a cosmetic composition to said fibers using an applicator as defined above. In such method, the brush according to the invention is loaded with the cosmetic composition and then the composition is applied to the surface to be made up, notably the eyelashes or the eyebrows. During the movement of the brush through the wiper member, the brush may follow a translational movement along the rectilinear axis of the stem. The brush may be used to make up the lashes at the corner of the eye, using a portion of the brush on the extrados near the distal end of the core. Such portion may carry a little quantity of composition due to the interference of the brush with the wiping member, and thus be useful for combing said lashes at the corner of the eye.

DETAILED DESCRIPTION

The invention may be understood better from reading the following detailed description of nonlimiting exemplary embodiments thereof and from studying the appended drawing, in which:

FIG. 1 shows, in schematic longitudinal section, one example of a cosmetic device according to the invention,

FIG. 2 is a side view in isolation of the brush of the device of FIG. 1 ,

FIG. 3 is a front view of the brush along arrow III of FIG. 2 ,

FIG. 4 is a perspective view of the brush,

FIG. 5 is a side view of a rough brush from which a brush according to the invention is made,

FIG. 6 is a front view along arrow VI of FIG. 5 ,

FIG. 7 shows the rough brush after machining,

FIG. 8 is a front view along arrow VIII of FIG. 7 ,

FIG. 9 and FIG. 10 illustrate the wiping of the brush during withdrawal of the applicator,

FIG. 11 to FIG. 14 are cross sections of variant embodiments of the brush,

FIG. 15 shows an example of stem and core assembly,

FIG. 16 is a similar view to FIG. 16 showing a variant embodiment of the stem and core,

FIG. 17 is a partial longitudinal section of a variant of a brush.

In the following description, identical elements or elements having identical functions bear the same reference sign. Their description is not repeated for each of the FIG.s, only main differences between the embodiments being mentioned.
The cosmetic device 1 shown in FIG. 1 comprises a container 2 containing a cosmetic composition P to be applied to the eyelashes or the eyebrows and an applicator 3 which may, in the example in question, be fixed removably to the container 2. The composition P comprises, for example, one or more pigments, notably an iron oxide. It is for example a mascara.
The applicator 3 comprises a stem 5, of rectilinear longitudinal axis Y, provided at a distal end 7 with a brush 10 according to the invention and at the other end with a cap 11 for closing the container 2 in a sealed manner. The latter has a body which is provided at the top with a threaded neck 14 onto which the cap 11 can be screwed in order to close the container 2. In an alternative form the applicator can be fixed to the container in some other way.
The neck 14 may accommodate, as illustrated, a wiping member 20 which is for example inserted into the neck 14. This wiping member 20 comprises a wiper lip 21 that defines a wiping orifice having a diameter D adapted to that of the stem 5, for example a diameter of 4.25 mm.
The brush 10 may be fixed, in a conventional manner, in a seat 8 (visible in FIG. 15 ) provided at the distal portion 6 of the stem 5, which is advantageously made of a thermoplastic material.
The brush 10 comprises a twisted metal core 40 comprising a curved portion 43 bearing bristles 41 and a rectilinear proximal portion 44, visible in FIG. 2 , that is inserted into the above-mentioned seat 8 provided at the distal portion 6 of the stem 5. The core 40 may be made by twisting together two strands of a U-shaped metal wire, the bristles being clamped by the turns of the wire. The diameter of the metal wire may vary and is for example of about 0.7 mm.
The free end of the bristles 41 define an envelope surface E with a shape that results from the trimming of the bristles 41 and the curvature imparted to the core 40 after trimming as will be described below.
The bristles 41 may be of any kind, with a circular cross section or better a non-circular cross section, for example a C-shaped cross section.
The bristles may be made of any material, preferably a thermoplastic material such as polyamide.
The outside diameter of the bristles may vary and for example is about 13/100 mm.
To manufacture the brush 10, one may start from the rough brush shown in FIG. 5 , having a straight core and an envelope surface with a cylindrical portion E1 and a frustoconical head portion E2. The overall length L of the bristle carrying portion may range from 20 to 35 mm, being for example of about 28 mm, while the length/of the frustoconical portion E2 may be of about 9 mm. The diameter d2 at the distal end of the frustoconical portion may be of about 4 mm, and the diameter d1 of the cylindrical portion of circular cross section may be about 7.5 mm, the invention being not limited to any specific value.
Then the bristles are trimmed to form three planar facets 51, 52 and 53 as shown in FIG. 7 and FIG. 8 .
Each of these facets extends over the whole length of the cylindrical portion E1 and a part of the frustoconical head portion E2, as one can see on FIG. 7 .
The angle h between the facets 51 and 52 may be about 60°, as shown in FIG. 8 , giving the cross section of the brush an overall triangular contour.
The facets 51, 52 and 53 are separated by circular arcs 55 in cross section.
Once the brush is trimmed, the bristle carrying portion 43 of the core is permanently deformed to impart the brush its final shape. The planar facets 51, 52 and 53 are deformed into facets 151, 152 and 153 of arcuate shape, respectively, the facet 153 extending along the extrados of the brush.
In the example shown, the radius of curvature R of the longitudinal axis X of the curved core portion 43 is constant and of about 40 mm. The longitudinal axis X of the curved portion 43 extends in a midplane M of the envelope surface E, that is a plane of symmetry.
The curved portion 43 has a convex side, that is left to the core in FIG. 2 and adjacent the extrados of the brush, and a concave side, that is right to the core in FIG. 2 .
According to the invention, the distal end 46 of the core 40 is offset from the longitudinal axis Y of the stem 5 by a non-zero distance f, the distal end 46 being offset on the convex side, i.e. being to the left of the longitudinal axis Y in FIG. 2 as is the extrados of the brush.
The angle w between on the one hand the straight line Z joining the core where it connect the distal end of the stem, that coincides substantially with the junction of the portions 43 and 44 of the core 40, and the distal end 46 of the core 40, and on the other end the longitudinal axis Y, is about 3.2° is the example shown.
Thanks to the offset of the distal end 46 of the core relative to the longitudinal axis of the stem 5, the wiping occurs more efficiently on the extrados of the brush, as will be explained further with reference to FIG. 9 and FIG. 10 .
FIG. 9 shows the brush 10 when it reaches the wiper lip 21 during withdrawal of the applicator from the container.
As one can see, the bristles of the facet 153 that first contact the wiper lip 21 have an abscissa x, measured along the longitudinal axis X of the curved portion 43 from the proximal end of origin x₀, that is relatively small, for example 3 mm or less.
Such a contact at an early stage of the withdrawal ensures that the facet 153 is wiped efficiently along almost all its length.
When the brush has almost entirely passed the wiper lip 21, as shown in FIG. 10 , the edge of the wiping lip comes relatively close to the curved portion of the core in the area A of the extrados near the distal end of the brush, thus providing strong wiping action in this area A.
The offset f is preferably however small enough so that when the applicator 3 is mounted on the container 2 with a displacement of the applicator 3 along the longitudinal axis Y, the distal end of the core engages in the wiping orifice without abutting against the wiper lip 21. This facilitates an automated mounting of the applicator 3 on the container 2.
In variant embodiments, the brush has other shapes in cross section.
For example, as shown in FIG. 11 , the brush may exhibit only one facet 153 on the envelope surface, on the extrados of the brush.
The facet 153 may be flat in cross section, as shown in FIG. 11 , or recessed, as exemplified in FIG. 12 to FIG. 14 .
In FIG. 12 , the facet 153 has a C-shape in cross section, in FIG. 13 a V-shape and in FIG. 14 a U-shape, but other forms of longitudinal notches are possible.
The offset of the distal end of the core according to the invention may allow the wiping of the bottom of the notch at least near in an area close to the distal end of the brush, thus leading to a wiped brush having a portion on its extrados with less composition left on it, better adapted to comb the lashes.
In the variant illustrated in FIG. 16 , the stem 5 has a rectilinear main portion 5 a that extends to the cap 11 and a relatively short rectilinear distal portion 5 b that extends along an axis K that makes an angle g with the axis Y of the main portion 5 a.
The core 40 is fixed in a seat 8 provided in the distal portion 5 b, with the curved portion 43 extending in a same plane as the plane defined by the axes Y and K. The convex side of the curved core 43 is oriented toward the left in FIG. 16 , as is the axis K below the main portion 5 a.
In the embodiment of FIG. 15 , the core 40 is angled right where it leaves the stem 5 to help provide the desired offset of the distal end of the core. In the embodiment of FIG. 16 , thanks to the angled distal portion 5 b of the stem, the core 40 may not need to be angled where it leaves the stem, as shown.
The invention also applies to injection molded brushes.
FIG. 17 shows an example of a brush 10 made by injection molding of one or more plastics material, such as thermoplastics elastomers, with application members 41 such as spikes made integrally with the core 40, in the same or in a different material.
The invention is not limited to the illustrative embodiments that have just been described, the features of which may be combined with one another within alternative forms that are not illustrated.

Claims

1. A cosmetic applicator for applying a composition to human keratinous fibers, notably eyelashes or eyebrows, comprising:

a stem having at least a rectilinear portion extending along a rectilinear axis,

a brush at one end of the stem, the brush comprising:

a curved core having a distal end and defining a convex side and an opposite concave side, the distal end of the core being offset from the rectilinear axis of the stem on the convex side of the core,

application members supported by the core.

2. The applicator of claim 1, the stem being rectilinear along its entire length.

3. The applicator of claim 1, the core being a twisted wire core.

4. The applicator of claim 1, the core being non rectilinear over its entire length from the stem to its distal end.

5. The applicator of claim 4, the core extending along a longitudinal axis of substantially constant radius of curvature from the stem to the distal end of the core.

6. The applicator of claim 5, the radius of curvature being greater or equal to 34 mm and less or equal to 47 mm.

7. The applicator of claim 1, the longitudinal axis of the core extending in a plane, preferably a midplane for an envelope surface of the brush defined by the application members.

8. The applicator of claim 1, the application members defining an envelope surface of non-circular cross section along at least part of its length.

9. The applicator of claim 8, the envelope surface defining at least one facet of flat or recessed cross section on the convex side of the core.

10. The applicator of claim 7, the cross section of the envelope surface having a plurality of rectilinear segments connected by circular arcs.

11. The applicator of claim 8, the cross section being of substantially triangular contour, with an apex preferably situated in a midplane for the envelope surface.

12. The applicator of claim 1, the tilt angle between the rectilinear axis of the rectilinear portion of the stem and a straight line joining the distal end of the core to the distal end of the rectilinear portion of the stem ranging from 0.5 to 10°, better 0.6 to 8°, preferably from 0.7° to 5.7° and more preferably from 2° to 4.5°.

13. The applicator of claim 1, the offset being not less than 0.5 mm and no greater than 2.5 mm.

14. The applicator according to claim 1, the application members being bristles or spikes that extend around the core.

15. A device for applying a cosmetic composition on keratinous fibers, comprising:

a container containing said composition, comprising a wiper member and,

an applicator as defined in claim 1.

16. The device of claim 15, the wiper member and the brush being configured so that when the applicator is withdrawn from the container along said rectilinear axis, application members situated on the convex side of the core, at an axial position less than 3 mm along the longitudinal axis of the core from the proximal end of the bristle portion of the brush, first contact the wiper member.

17. A method for manufacturing a brush for use in an applicator as defined in claim 1, comprising:

machining a twisted wire core brush with a rectilinear core to form at least one planar or recessed face of an envelope surface defined by the free ends of the bristles, the core having a proximal portion for fixing into a stem and a bristle carrying portion,

deforming the core to impart to the bristle carrying portion a curved shape with a convex side and a concave side, the distal end of the core being offset from the longitudinal axis of the proximal portion on the convex side of the core.

18. The method of claim 17, the core being deformed along a plane of curvature, the machining comprising forming three planar facets of the envelope surface, giving the envelope surface a substantially triangular shape in cross section, an apex lying in the plane of curvature of the core.

19. The method of claim 17, the machining comprising forming a frustoconical head portion.

20. The method of claim 18, the planar facets intersecting the frustoconical head portion.

21. The method according to claim 17, the deforming of the core comprising imparting the bristle carrying portion a constant curvature then tilting the core at the junction of the bristle carrying portion with the proximal portion, or vice versa.

22. A method for manufacturing a brush for use in an applicator as defined in claim 1, comprising injection molding the core and the application members in at least one plastics material.

23. A method for making up human keratinous fibers, comprising applying a cosmetic composition to said fibers using an applicator as defined in claim 1.