Cosmetic product applicator

An applicator for a cosmetic product on the skin or bristles having an application member, made of a thermoplastic elastomer material, the application member including a core extending along a longitudinal axis, and application elements formed at the surface of the application member, each of the application elements having a top with a width greater than 35 μm and smaller than 450 μm.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to and claims the benefit of French Patent Application Number 2213878 filed on Dec. 19, 2022 and French Patent Application Number 2301115 on Feb. 6, 2023, the entire contents of both of said applications are herein incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to the field of make-up cosmetic product and skin care product applicators. The present disclosure relates more particularly to flocked-texture applicators for applying in particular lip gloss or lip oil and a concealer, and possibly mascara. The disclosure also relates to a method for manufacturing such an applicator.

BACKGROUND

The applicators in particular for lip gloss or lip oil generally have a flock formed of bristles bonded to a support. Such a flock requires several manufacturing steps to assemble parts made of different materials. As a result, the applicator is difficult to recycle.

The patent application US2019/0343262 describes a cosmetic applicator including a hard plastic frame and silicone bristles radially arranged and covering the external periphery of the frame. Due to the fragility of the bristles, this applicator cannot be manufactured by conventional injection molding, but by vacuum injection molding.

The patent application US2008/0083421 describes a mascara applicator likely to be molded in one piece by injection including a rod, a hub formed at the end of the rod, and members provided with bristles extending radially from the hub. The members are intended to be kept folded along the rod, the bristles on the members extending substantially radially from the axis of the rod.

The patent application US2021/0323205 describes a method for manufacturing a cosmetic applicator comprising a step of injection molding a thermoplastic material. This molding step involves a mold whose inner surface has micro-engraved cavities intended to form a flock.

The formation of flock or bristles by molding leads to numerous defects during molding and demolding in particular due to the very fine shapes of the flock or the bristles.

The patent application FR 3 091 983 also describes a method for manufacturing a cosmetic product applicator comprising steps of mixing the thermoplastic material with an inert gas and injecting the mixture into a mold, to obtain a microporous surface structure.

It is therefore desirable to propose a cosmetic or skin care product applicator with a flocked texture that is effective, both in supporting the product, and in transferring it to the skin or to the eyelashes or eyebrows. It can also be desirable for the applicator to be easily manufactured, by injection molding of a thermoplastic elastomer material, and with the lowest possible rate of manufacturing defects.

BRIEF SUMMARY

Embodiments relate to an applicator for a cosmetic product on the skin or bristles, comprising an application member made of a thermoplastic elastomer material, the application member comprising: a core extending along a longitudinal axis, and application elements formed on the surface of the application member, each of the application elements having a top with a width greater than 35 μm and smaller than 450 μm.

Such an applicator has the advantage of being able to be produced only by molding, while having a flocked texture, which can be easily demolded due to the enlarged, substantially flat tops of the application elements.

According to one embodiment, the top of the application elements has a length larger than their width.

In this way, it is possible to obtain a surface having both more and less hydrophobic properties according to the relevant direction. The hydrophobic character can be adapted depending on the cosmetic product to be applied, simply by adjusting the dimensions of the tops and the distances between the tops of the application elements.

According to one embodiment, the top of the application elements have a rectangular shape, or the application elements have the shape of parallel ribs.

This arrangement allows combining hydrophilic and hydrophobic characters, capable of both sufficiently retaining the cosmetic product, and easily transferring the latter to the skin or the eyelashes.

According to one embodiment, the application elements have a width comprised between 40 and 400 μm.

These dimensions are particularly adapted to the function of applying a cosmetic product.

According to one embodiment, the application elements have a height comprised between 350 and 600 μm.

Such a depth allows retaining a sufficient quantity of cosmetic product, without disturbing the hydrophobic character of the relief formed by the application elements. Furthermore, the application elements can deform during the application and release the product accumulated between them.

According to one embodiment, the application elements, are spaced apart from each other by a distance comprised between one and two and a half times the width of the top of the application elements.

Such a distance allows retaining a sufficient quantity of the cosmetic product, while offering the required hydrophobic character.

According to one embodiment, the core has a circular or helical-shaped groove.

This groove allows retaining an additional quantity of cosmetic product.

According to one embodiment, the core comprises two drop-shaped portions arranged along the longitudinal axis, the two portions delimiting between them an annular groove.

This shape has a good ergonomic while allowing retaining an additional quantity of cosmetic product.

According to one embodiment, the application member comprises a plurality of parts engaged on a rod of the applicator, the application elements being formed on all or part of the surface of the parts.

According to one embodiment, each of the parts comprises two fin-shaped portions connected to each other by a portion forming a hub in which the rod of the applicator is engaged, the fin-shaped portions forming fins about the rod of the applicator.

According to one embodiment, each of the parts has the shape of a star with a hub in which the rod of the applicator is engaged and radial elements extending radially about the hub.

Embodiments may also relate to a method for manufacturing a cosmetic applicator as previously defined, the method comprising a step of molding a thermoplastic elastomer material, using a mold complementary in shape to that of the applicator, having a plurality of cavities complementary in shape to those of the application elements of the applicator.

The particular shape of the applicator with application elements having a top with a relatively large width, enables it to be manufactured in a single molding step, with a low risk of breakage of the application elements during demolding. As a result, the number of manufacturing defects is reduced and the cleaning operation of the mold which may be required to be performed between two molding operations is simplified.

According to one embodiment, the method comprises a step of manufacturing a mold, the cavities being formed using a femtosecond laser.

The properties of the surfaces formed by such a laser allow both obtaining an easy demolding with a low risk of breakage and molding surfaces having a good affinity for the cosmetic products to be applied.

Embodiments may also relate to a mold for manufacturing a cosmetic product applicator as previously defined, the mold comprising a molding surface having a plurality of cavities complementary in shape to those of the application elements of the applicator.

DETAILED DESCRIPTION

FIG.1represents a cosmetic applicator1comprising a rod11having a longitudinal axis X, secured to an applicator member12comprising a core13carrying a plurality of application elements14distributed over at least one portion of the surface of the core13.

In the example ofFIG.1, the core13has an elongated shape according to its longitudinal axis X, and a substantially conical distal end.

According to an embodiment illustrated byFIGS.2and3, each application element14of at least one portion of the application elements14has a top15with a width L1, which can extend in a surface parallel to a portion of the surface16of the core13where the application element is located. The application elements14extend over a height H1above the surface16of the portion of the core13where they are located. The tops15of the application elements14of the portion of the application elements14are spaced apart from each other by a distance D1. The tops of the application elements14are substantially flat to within 10% of the height H1.

The shape of the application elements14with a wide top, has the advantage of being easy to demold, in particular by reducing the risk of breakage of the ends of the application elements in the mold reliefs.

According to one embodiment, the distance D1between the application elements14is comprised between one and three times the width L1. According to one embodiment, the width L1of the application elements14is comprised between 80 and 160 μm, and preferably comprised between 90 and 150 μm. The distance D1between the application elements14is comprised between 80 and 160 μm, and preferably comprised between 90 and 150 μm. The maximum height H1of the application elements14is comprised between 350 and 600 μm. In the direction of the ends of the core13along the longitudinal axis X, the application elements14may have a decreased height H1, as shown inFIG.1.

In the example ofFIG.3, the application elements14have a circular-shaped top with a diameter L1.

According to one embodiment, the applicator1is manufactured in one piece using a mold, by injection of a thermoplastic elastomer (TPE) material.FIG.4represents an example of such a mold9. In the example ofFIG.4, the mold9is for example formed of two mold halves9a,9bdelimiting between them a volume corresponding to that of the applicator1. This volume comprises a portion91allowing molding the rod11and a portion92allowing molding the core13of the applicator1and the application elements14. To mold the application elements14, the mold halves9a,9bhave a plurality of cavities94formed in the walls93delimiting the core13. The molding surfaces of the mold halves9a,9bmay have identical shapes.

According to one embodiment, the cavities94are made of the material forming the mold halves9a,9busing a femtosecond laser. Such a laser allows making a relief in a mold surface with sufficient accuracy to form the application elements14, the lateral faces17of the application elements14being substantially perpendicular (to within 15°) to the surface16of the core13. This technique for forming the cavities94also has the advantage of forming a relief and surfaces having a good affinity for the cosmetic products to be applied.

It should be noted that the enlarged and flat or substantially flat shape of the tops15of the application elements14reduces the risk of breakage during demolding, relative to sharp application elements. The cleaning operation of the mold between two molding operations is therefore simplified.

It should also be noted that the cavities94are directed perpendicular to the interface plane between the two mold halves and therefore can be easily produced by directing the laser perpendicular to this plane.

The applicator1can be made of a thermoplastic elastomer TPE such as SEBS (polystyrene-b-poly(ethylene-butylene)-b-polystyrene) and/or of a thermoplastic material having a hardness of around 30 shore A (to within + or −10%). The SEBS has the advantage of being pleasant to the touch and therefore suitable for contact with the skin.

FIG.5represents a relief formed by application elements64produced on the surface of the core13, according to another embodiment. Each of the application elements64has a rectangular-shaped top65with a width L1and a length L2. The tops15of the application elements64are spaced apart from each other in the direction X1of the width L1by a distance D1and in a direction X2of the length L2by a distance D2. The application elements64may also have the height H1above the surface16of the core13. According to embodiments, the width L1and the length L2are respectively comprised between 150 and 250 μm and between 350 and 450 μm, and are preferably respectively equal to 200 and 400 μm (to within + or − 10%). The distances D1and D2are comprised between 350 and 450 μm, and are preferably equal to 400 μm (to within + or −10%).

FIG.6represents a relief formed by application elements74produced on the surface of the core13, according to another embodiment. Each of the application elements74has a rib-shaped top75with a width L1. The tops75of the application elements74extend parallel to one another and are spaced apart from each other by a distance D1. The application elements74may also have the height H1above the surface16of the core13. The rib-shaped application elements74may have an annular or helical shape about the core13(about the longitudinal axis X). According to embodiments, the width L1is comprised between 40 and 400 μm, and preferably comprised between 200 and 400 μm. The distance D1between the tops of the ribs is comprised between 350 and 450 μm, and is preferably equal to 400 μm (to within + or − 10%).

Any other shape of the top of the application elements14may also be suitable as an elliptical shape, or a polygonal shape inscribed in a circle or in an ellipse.

FIG.7represents a water drop9deposited on the surface of the tops15,65,75of the application elements14,64,74.FIG.7also shows an angle A1between the surface15,65,75and a line tangent to the drop9at an intersection point between the drop and the surface15,65,75. It is understood here that the smaller the angle A1, the greater the penetration of the drop9into the relief and therefore the more the relief has a hydrophilic character. Inversely, at the angles greater than 90°, the surface is generally considered to have a hydrophobic character.

Table 1 groups examples of top dimensions and distances between the tops and the angles A1measured in the perpendicular directions X1and X2, indicated inFIGS.5and6, the direction X1being parallel to the length of the rectangles65or the ribs75.

In the case of the rectangular-shaped tops65(FIG.5), the distance D2is selected to be equal to the distance D1.

Table 1 shows that the ribs (FIG.6) and the rectangular shapes (FIG.5) have a stronger hydrophobic character (angle A1greater than 90°) in the direction X1than in the direction X2. It also proves that the hydrophobic surfaces are often lipophilic and reciprocally, the hydrophilic surfaces are often lipophobic. In the scope of the applicators for cosmetic products which are generally greasy substances, this aspect may advantageously be exploited to obtain both a good retention of the cosmetic product on the applicator and a good availability of the product to be able to be easily transferred and spread from the applicator to the skin or to the eyelashes or the eyebrows.

FIGS.8and9represent applicators2,3, produced in one piece by a single molding operation, according to other embodiments. InFIG.8, the applicator2comprises a rod21having a longitudinal axis X. The rod21is secured to an application member22comprising a core23carrying a plurality of application elements24distributed over at least one portion of the surface of the core23. The core23has an elongated shape according to its longitudinal axis X, and a substantially conical distal end. The core23further comprises a groove26extending about the axis X. The groove26acts as a reservoir to retain more cosmetic product. The groove26may have a circular (FIG.8) or helical shape.

InFIG.9, the applicator3comprises a rod31having a longitudinal axis X. The rod31is secured to an application member32comprising a core33carrying a plurality of application elements34distributed over at least one portion of the surface of the core33. The core33has a shape combining two water drop-shaped portions37,38, whose longitudinal axes of revolution coincide with the axis X. The water drop shapes37,38delimiting between them an annular groove36which can also act as a reservoir of cosmetic product. The water drop shape38on the distal side of the core33can be smaller than the water drop shape37on the proximal side of the core.

It will be clear to those skilled in the art that the present disclosure is open to diverse variants and diverse applications. In particular, the disclosure is not limited to the previously described applicator shapes. Other applicator shapes may be suitable when the applicator has a relief with application elements having enlarged, substantially flat tops, likely to retain a cosmetic product and to transfer it to the skin or to the bristles (eyelashes, eyebrows).

Nor is the disclosure limited to an application member formed in one piece. Indeed, it may be envisaged to manufacture the application member by assembling several parts, for example by interlocking. These parts may include at least one surface on which application elements are formed. As previously, the application elements can have a top with a width greater than 35 μm and smaller than 450 μm. Each of these parts can be formed using a mold with a complementary shape and having a surface including cavities which can be produced using a femtosecond laser, to form the application elements. The different parts forming the core of the application member may or may not be identical.

According to an embodiment illustrated byFIGS.10and11, the assembled parts forming the core of the applicator4comprise parts43formed of two substantially rectangular-shaped portions44a,44bconnected to each other by a portion45a-45eforming a hub whose axis Z is parallel to an inner edge46of each rectangular portion. The parts are assembled to form the applicator using the rod41of the applicator, engaged in the hub45a-45eof each of the parts43, so as to form rectangular-shaped fins44a,44bdistributed about the rod41, in a same position along the longitudinal axis X of the rod41which coincides with the axis Z of the hubs45a-45e. To this end, the respective hub45a-45eof each of the parts43is arranged relative to the fins44a,44bat distinct locations along the axis Z spaced apart from the length of the hubs. In the example ofFIGS.10and11, the applicator4comprises five parts43each including two fins44a,44b.

According to an embodiment illustrated byFIGS.10and11, the outer edges47of the fins44a,44bmay have corrugations, in particular in order to facilitate the application of the cosmetic product.

According to one embodiment, the application elements14,64,74are formed on all or part of the faces of the parts43. To this end, the corresponding faces of the molds allowing manufacturing the parts43may be treated using a femtosecond laser to form the cavities94at the desired locations. If required, a mirror system may be used to direct the laser beam on some faces of the mold, for example on the faces forming the thickness of the fins44a,44b. It should be noted that all parts43can be manufactured in a single molding step using a same mold comprising one molding cavity per part.

According to another embodiment illustrated byFIGS.12and13, the fins44a,44bare cut in the form of combs. Thus in the example ofFIGS.12and13, the applicator4′ comprises parts43′ forming fins44a′,44b′ whose corrugated outer edges are cut so as to form teeth48, the set of teeth48of each fin44a′,44b′ forming a comb. The applicator4′ can thus be adapted so that the teeth48can pass between the eyelashes.

According to one embodiment, the hub45a-e,45a′ of the parts43,43′ comprises axial ribs47formed inside the hub. The ribs47are intended to cooperate with slots with a complementary shape formed on the rod41,41′ of the applicator. Thus, the parts43,43′ can be introduced on the rod41,41′ only in a determined angular position about the axis X of the rod. This arrangement allows for example uniformly distributing the fins44a,44b,44a′,44b′ about the rod41,41′.

According to one embodiment, the hub45a-e,45a′ of the parts43,43′ comprises axial slots47formed on the outer face of the hub. These slots are intended to receive the internal edges of the other parts43,43′ when the latter are engaged on the rod41,41′ to form the applicator4,4′.

According to another embodiment illustrated byFIGS.14and15, the assembled parts forming the core of the applicator5comprise star-shaped parts53, which are substantially flat and mounted coaxially on the rod51of the applicator. The parts53comprise a hub55and radial elements54extending radially about an axis Z of the hub55. The hub55can be thicker than the radial elements54in the direction of the axis Z, to space the latter along the longitudinal axis X of the applicator5. In the example ofFIGS.12and13, the applicator5comprises about 50 parts53and each of the parts53comprises 15 radial elements54. The radial elements have a straight rectangular-shaped section.

According to one embodiment, the application elements are formed on all or part of the faces of the parts53. To this end, the corresponding faces of the molds allowing manufacturing the parts53can be treated using a femtosecond laser to form the cavities94at the desired locations. If required, a mirror system can be used to direct the laser beam on some faces of the mold, for example on the faces forming the thickness of the radial elements54. All parts53may have identical shapes, they can be manufactured using a same mold.

According to one embodiment, the hub55of the parts53comprises axial ribs57formed inside the hub. The ribs57are intended to cooperate with slots with a complementary shape formed on the rod51of the applicator5. Thus, the parts53can be introduced on the rod51only in a determined angular position about the axis X of the rod. This arrangement allows for example aligning the free ends of the radial elements54along an axis parallel to the axis X of the rod51, or arranging them differently, for example so as to distribute these ends along helices. It should be noted that the slots formed on the rod51are not necessarily aligned in the direction of the axis X, but can also follow a helical trajectory.

In addition, it may also be considered to mold the applicator or the different parts forming the applicator by injecting the thermoplastic material into the mold, mixed with an inert gas to obtain a foamy appearance.