Patent Publication Number: US-2017360177-A1

Title: Unit for applying a cosmetic product

Description:
The present invention relates to a unit for applying a cosmetic product on human keratin materials, particularly eyelashes or eyebrows. 
     A “cosmetic product” means any composition such as that defined in Council Directive 93/35/EEC dated Jun. 14, 1993. 
     More specifically, the present invention relates to a unit for applying a cosmetic product for an applicator, comprising a receiving area of the application unit, said application unit comprising: a substantially longitudinal holder, said holder comprising a first portion suitable for securing said holder removably to said receiving area, and a second portion that forms at least one compartment for receiving the cosmetic product; and a mass of cosmetic product to be applied to human keratin materials, said cosmetic product being different from a material that forms the holder. 
     From the application EP 1 955 610, an applicator tip is known, exclusively consisting of an eyelash makeup composition, molded and suitable for being mounted by press fitting onto a heating holder shaped in the form of a finger. However, such a tip consisting of cosmetic product mounted directly on the heating holder soils this holder which requires cleaning after each use. Furthermore, handling tips solely consisting of a makeup composition is liable to cause soiling of the user&#39;s fingers. 
     The Applicant has provided solutions to these problems by means of an application unit of the type mentioned above, particularly described in the document WO2011/131907. Such an application unit is typically manufactured according to a two-step injection molding method, as described in said document. 
     However, the shapes of current application units may give rise to deformation of the holder during certain steps of the production process. 
     In order to solve this problem, the invention relates to an application unit of the type mentioned above, wherein an outer surface of the mass of cosmetic product includes at least one longitudinal bulge extending continuously, substantially over the entire second portion of the holder. 
     According to further advantageous aspects of the invention, the application unit comprises one or several of the following features taken in isolation or in any technically possible combination:
         the holder comprises at least two reception compartments separated from one another by ribs;   the ribs extend substantially transversally to the holder, an outer surface of said ribs being partially covered by the longitudinal bulge;   the application unit comprises a longitudinal element connecting at least two transversal ribs, an outer surface of said longitudinal element being covered with cosmetic product;   the holder and the mass of cosmetic product are curved with respect to a longitudinal axis, the reception compartments and the mass of cosmetic product being arranged in a concavity of the curve.   the outer surface of the mass of cosmetic product comprises two longitudinal bulges, extending continuously, substantially over the second portion of the holder, said two bulges being arranged symmetrically with respect to a longitudinal plane of symmetry of the holder.       

     The invention also relates to a method for producing a unit for applying a cosmetic product as described above, said method comprising the following steps: providing a first half-mold having a first cavity and a second half-mold having a second cavity, the first and second cavities defining a first injection volume to form the holder; injecting a first material into the first injection volume to form the holder; separating the first and second half-molds, the holder remaining in the first cavity; providing a third half-mold having a third cavity, the first and second cavities defining a second injection volume to form the mass of cosmetic product; injecting cosmetic product into the second injection volume to form the mass. The third cavity comprises a groove for the formation of the longitudinal bulge. 
     According to further advantageous aspects of the invention, the method comprises one or several of the following features taken in isolation or in any technically possible combination:
         an injection point of the cosmetic product is located substantially on a longitudinal plane of symmetry of the holder;   the third cavity comprises two grooves for the formation of two longitudinal bulges, said grooves being arranged symmetrically with respect to a longitudinal plane of symmetry of the second injection volume.       

     The invention further relates to an assembly comprising: a unit for applying a cosmetic product as described above; and an applicator comprising a heating receiving area suitable for receiving the application unit, the heating receiving area being suitable for heating the mass of cosmetic product to a temperature inducing a change of state of said cosmetic product. 
    
    
     
       The invention will be easier to understand in view of the following description, provided solely as a non-restricted example and with reference to the drawings, wherein: 
         FIG. 1  is a perspective view of an element of an assembly according to an embodiment of the invention; 
         FIG. 2  is a perspective view of an application unit according to an embodiment of the invention; 
         FIG. 3  is a longitudinal cross-section view of the application unit of  FIG. 2 ; 
         FIG. 4  is a longitudinal cross-section view of the application unit of  FIGS. 2 and 3 , during a first step of a manufacturing method according to an embodiment of the invention; 
         FIG. 5  is a transversal cross-section view of the application unit of  FIGS. 2 to 4 , during a second step of said manufacturing method. 
     
    
    
       FIG. 1 , on one hand, and  FIGS. 2 and 3 , on the other, represent two elements  10 ,  30 , respectively, of an assembly for applying a cosmetic product, according to an embodiment of the invention. Said assembly is particularly intended for the application of a cosmetic product on human keratin materials, particularly eyelashes or eyebrows. 
       FIG. 1  represents a heating applicator  10 , similar to an applicator described in the document WO2011/131907. The applicator  10  comprises a gripping handle  12  extending essentially along a longitudinal axis  14 . The applicator  10  further comprises an application rod  16 , which extends the handle  12  along the axis  14 . 
     An orthonormal basis (X, Y, Z) is taken into consideration, the axis  14  being parallel with the direction X. 
     The rod  16  comprises an electrical heating element, connected to an electrical power source housed in the handle  12 . The rod  16  comprises for example a metallic tubular casing  18  containing an electrical insulating core (not shown), said core being traversed by a resistive electrical conductor (not shown) extending over the entire length of the casing  18 . 
     The electrical heating element has for example a rated power between 0.5 and 2 W and makes it possible to attain a temperature greater than 50° C., for example a temperature of 70° C. for an ambient temperature of 20° C. 
     The electrical power source housed in the handle  12  is for example an electric battery. The heating is actuated by means of a switch  17  situated on the handle  12 . 
     One end of the rod  16 , opposite the handle  12 , forms a receiving area  20  of a unit for applying cosmetic product. In the embodiment of  FIG. 1 , the receiving area  20  has a curved shape in a plane (X, Y). The curve is substantially in the arc of a circle. Preferentially, the curve has a radius of curvature between 10 and 100 mm, more preferentially between 20 and 30 mm, for optimal suitability to the application of the product on eyelashes. 
       FIGS. 2 and 3  show a unit  30  for applying cosmetic product according to an embodiment of the invention. The application unit  30  is suitable for being assembled with the receiving area  20  of the applicator  10  of  FIG. 1 . 
     The application unit  30  has an elongated shape and extends substantially along a longitudinal axis  32 . When the application unit  30  is assembled with the receiving area  20  of the applicator  10 , the axes  14  and  32  are merged. 
     The same orthonormal basis (X, Y, Z) as in  FIG. 1  is taken into consideration, the axis  32  being parallel with the direction X. 
     The application unit  30  comprises a plastic holder  34  and a mass  36  of cosmetic product P, borne by the holder  34 . 
     The application unit  30 , and thus the holder  34  and the mass  36 , have a plane of symmetry (X, Y) containing the axis  32  and corresponding to the cutting plane of  FIG. 3 . 
     The holder  34  has the shape of a tubular sleeve, so as to be suitable for being fitted onto the rod  16  at the receiving area  20 . An internal wall  38  of the holder  34  has a substantially complementary shape with an external shape of the metal casing  18 , at the receiving area  20 . 
     The holder  34  comprises two longitudinal sections  40 ,  42 , substantially arranged along the axis  32 . At the ends thereof along said axis  32 , the longitudinal sections  40 ,  42  are connected by the proximal  44  and distal  46  ends of the holder  34 . The distal end  46  corresponds to the furthest end from the handle  12  when the application unit  30  is assembled with the receiving area  20  of the applicator  10 . The distal end  46  comprises a solid wall arranged along a plane (Y, Z). On the other hand, the proximal end  44  is open in order to be able to fit the application unit  30  onto the receiving area  20  of the rod  16 . 
     The longitudinal sections  40 ,  42  and the proximal  44  and distal  46  ends partially form the internal wall  38  of the holder  34 , which is suitable for removably securing said holder  34  onto the receiving area  20 . 
     Moreover, a frame formed by the longitudinal sections  40 ,  42  and the proximal  44  and distal  46  ends defines an area  48  suitable for containing a cosmetic product. 
     Preferably, the holder  34  comprises a longitudinal slot  50 , separating the longitudinal sections  40 ,  42 . The slot  50  enables the holder  34  to be deformed elastically by molding the shape of the receiving area  20 . In this case, an internal cross-section of the holder  34  at rest is slightly smaller than the cross-section of the receiving area  20 . 
     The slot  50  extends preferentially over at least 50% of a length of the holder  34  along the axis  32 , more preferentially over at least 90% of said length. The slot extends preferentially in the plane of symmetry (X, Y) of the unit  30 . 
     The slot  50  has for example a width between 0.5 mm and 1.5 mm, measured between the two longitudinal sections  40  and  42 . 
     In the embodiment of  FIGS. 2 and 3 , the holder  34  is slightly curved in the plane of symmetry (X, Y) of the unit  30 . The holder  34  can thus mold the curve of the receiving area  20  as represented in  FIG. 1 . The slot  50  is situated on the convex side of the curve. 
     On the concave side of the curve, the area  48  of the holder  34  comprises a series of ribs  52 . Each of the ends of the ribs  52  rests on a longitudinal section  40 ,  42  of the holder  34 . In the embodiment in  FIGS. 2 and 3 , the ribs  52  are parallel with one another and oriented transversally, i.e. along the planes (Y, Z). According to one alternative embodiment described in the document WO2011/131907, the ribs  52  are inclined with respect to the planes (Y, Z). 
     Preferentially, the holder  34  comprises between two and twenty ribs. Preferentially, the holder  34  comprises an even number of ribs, for reasons detailed hereinafter. In the example in  FIGS. 2 and 3 , the holder  34  comprises sixteen ribs. 
     A thickness of the ribs  52 , measured along the direction X, is preferentially between 0.5 mm and 1.5 mm. 
     As seen in  FIG. 5 , in a cross-section along a plane (Y, Z), the ribs  52  of the holder  34  have a crescent shape, between an internal profile  54  and an external profile  56 . The internal profile  54  of the ribs  52  is part of the internal wall  38  of the holder  34 . 
     In the example in  FIG. 3 , the holder  34  comprises a longitudinal ridge  58  connecting the transversal ribs  52 . The ridge  58  is in the form of a thread arranged at the internal profile  54  of the ribs  52 . The ridge  58  is part of the internal wall  38  of the holder  34 . The ends of the ridge  58  are respectively connected to the proximal  44  and distal  46  ends of the holder  34 . The ridge  58  reinforces the structure formed by the transversal ribs  52 . 
     The ridge has for example a substantially rectangular cross-section in a plane (Y, Z), one side of the rectangle having for example a length between 0.1 mm and 0.5 mm. 
     In the example of  FIG. 3 , the ridge  58  is arranged in the plane of symmetry (X, Y) of the unit  30 . According to an alternative embodiment not shown, the ridge  58  is arranged in a further plane (X, Y). According to a further alternative embodiment not shown, the holder  34  comprises at least two longitudinal ridges connecting the transversal ribs  52 , said ridges being preferentially parallel with one another. 
     As seen in  FIG. 3 , two consecutive ribs  52  have crescent-shaped surfaces  60 ,  62  situated facing one another in planes (Y, Z). 
     The ridge  58  and the surfaces  60 ,  62  define compartments  64  for receiving cosmetic product. 
     The holder  34  is for example made of plastic, particularly of a polyolefin such as polyethylene (PE) or polypropylene (PP) or, alternatively, of non-polyolefinic materials such styrene-acrylonitrile (SAN), acrylonitrile-butadiene-styrene (ABS) or polyoxymethylene (POM). These plastic materials are optionally charged with particles or mineral fibers, for example metal oxides, glass or carbon black powder or fiber in order for example to enhance and/or control heat transfer in the holder  34  to the cosmetic product P and/or enhance the rigidity of the holder  34 . 
     The mass  36  of cosmetic product P is rigidly connected to the holder  34  at the area  48  end, the cosmetic product P being particularly received in the compartments  64  between the ribs  52 . 
     The mass  36  has an inner surface  66 , particularly situated between the internal profiles  54  of the ribs  52 . The inner surface  66  of the mass  36  is continuous with the inner surface  38  of the holder  34 . The inner surfaces  38 ,  66  define a complementary shape of the external shape of the receiving area  20  of the applicator  10 . When the application unit  30  is assembled with the receiving area  20 , the inner surface  66  of the mass  36  is in contact with the casing  18  of the rod  16 . 
     The mass  36  further has an outer surface  68 , intended to come into contact with keratin fibers. At the plane of symmetry (X, Y) of the unit  30 , the external profile  56  of the ribs  52  is flush with the outer surface  68  of the mass  36 . At said plane of symmetry, the ribs  52  are thus visible from outside the application unit  30 . 
     As seen in  FIG. 2 , the mass  36  also has two longitudinal bulges  70 ,  72 , partially forming the outer surface  68 . The bulges  70 ,  72  extend continuously along the application unit  30 , substantially over the entire area  48  receiving the cosmetic product P. The bulges  70 ,  72  of cosmetic product P cover the ribs  52 , which are thus not visible from the outside at said bulges. 
     In the example in  FIG. 2 , the longitudinal bulges  70 ,  72  are arranged symmetrically with respect to the plane of symmetry (X, Y) of the unit  30 . Further arrangements of the bulges are possible. According to alternative embodiments not shown, the application unit  30  comprises a single longitudinal bulge, or more than two bulges. 
     The cosmetic product P forming the mass  36  is for example an eyelash makeup composition having a property which varies according to the temperature. Said property is for example a smooth-flowing nature, particularly of d max ≧ to 5 mm, d max  being determined according to the protocol described in paragraphs [0120] to [0127] of the document EP 1 955 610. 
     The cosmetic product P is for example a composition comprising at least one reversible polymer solid at ambient temperature. The term “solid” denotes a product which does not flow under the effect of gravity at 20° C. 
     The cosmetic product P comprises for example at least one compound chosen from the following list:
         polymers and copolymers comprising at least one alkene monomer, in particular copolymers based on ethylene,   vinyl polyacetate homopolymers,   silicone resins,   film-forming sequenced ethylene polymers, preferably comprising at least one first sequence and at least one second sequence having different vitreous transition temperatures (Tg), said first and second sequences being connected together by an intermediate sequence comprising at least one monomer constituting the first sequence and at least one monomer constituting the second sequence,   diene and styrene copolymers,   sulfopolyesters,   alkene and vinyl acetate copolymers, in particular ethylene and vinyl acetate copolymers;   ethylene and octene copolymers,   vinyl polyacetate homopolymers,   silicone T resins, such as polyphenylsiloxanes,   film-forming sequenced ethylene copolymers, essentially derived from monomers chosen from alkyl methacrylates, alkyl acrylates, and mixtures thereof,   butadiene and styrene copolymers,   copolymers obtained by condensing di-ethyleneglycol, cyclohexane di-methanol, isophthalic acid, sulfoisophthalic acid, and mixtures thereof.       

     Preferably, the cosmetic product P has a melting point greater than or equal to 50° C., for example approximately 54° C. 
     Preferentially, the holder  34  bears a mass  36  comprising between 10 mg and 100 mg of cosmetic product P, more preferentially between 20 mg and 50 mg of product, even more preferentially approximately 30 mg of product. This quantity is particularly suitable for single use, making it possible for example to apply makeup on one or two eyelash fringes. 
     In the example in  FIGS. 1 to 3 , the receiving area  20  of the applicator  10  and the application unit  30  are curved as defined above. According to one alternative embodiment not shown, the receiving area  20  and the application unit  30  have a substantially rectilinear shape along the axes  14  and  32 . 
     A method for manufacturing the application unit  30  will now be described, with reference to  FIGS. 4 and 5 . This consists of an injection molding method, similar to the method described in the document WO2011/131907. The term “injection molding” denotes the molding of a part by injecting a material in the fluid state, under a pressure greater than atmospheric pressure, in a closed volume except for a material injection orifice. 
     A device for manufacturing the application unit  30  particularly comprises a first half-mold  80  and a second half-mold  82 . 
     The first half-mold  80  comprises at least one first cavity  84 . Preferentially, the first half-mold  80  comprises a series of identical first cavities  84 . The second half-mold  82  comprises at least one second cavity  86 . Preferentially, the second half-mold  82  comprises a series of identical second cavities  86 . When the first half-mold  80  and the second half-mold  82  are arranged in contact with one another as in  FIG. 4 , each first cavity  84  coincides with a second cavity  86  so as to define a first volume  88  for injecting material to form the holder  34 . 
     The second half-mold  82  further comprises an injection channel  90  leading to the second cavity  86  at a first injection point  92 . By way of example, the first injection point  92 , represented in  FIG. 2 , is situated on the proximal end  44  of the holder  34  in the plane of symmetry (X, Y) of the unit  30 . 
     Preferentially, the second half-mold  82  comprises a series of identical injection channels  90 , each of the channels leading to a second cavity  86 . 
     In a first step for manufacturing the application unit  30 , the first half-mold  80  and the second half-mold  82  are arranged in contact with one another. A material  94  in the fluid state is then injected into the first injection volume  88  via the injection channel  90 , so as to form the holder  34 . As represented in  FIG. 4 , the first injection volume  88  is then entirely filled with material  94 . 
     The material  94  is preferentially injected at a temperature greater than 110° C. so that the material is in the fluid state. Once the injection is complete, the assembly of the first half-mold  80  and the second half-mold  82  is cooled to solidify the material  94 . 
     The first half-mold  80  and the second half-mold  82  are then separated. The holder  34 , obtained by cooling the material  94 , remains in the first cavity  84  of the first half-mold  80 . 
     The first half-mold  80  is then placed in contact with a third half-mold  96  as represented in  FIG. 5 . 
     The third half-mold  96  comprises at least one third cavity  98 . The first cavity  84  coincides with the third cavity  98  so as to define, with the holder  34 , a second injection volume  99  of cosmetic product P to form the mass  36 . 
     As seen in  FIG. 5 , the third cavity  98  comprises two longitudinal grooves  100 ,  102  for the formation of the longitudinal bulges,  70  and  72  respectively. The longitudinal grooves  100 ,  102  are arranged symmetrically with respect to the plane of symmetry (X, Y) of the unit  30 . 
     Preferentially, the third half-mold  96  comprises a series of identical third cavities  98 . When the first half-mold  80  and the third half-mold  96  are arranged in contact with one another as in  FIG. 5 , each first cavity  84  coincides with a third cavity  98  so as to define a second injection volume  99 . 
     The third half-mold  96  further comprises an injection channel  104 , represented by a dotted line in  FIG. 5 . The injection channel  104  leads to the third cavity  98  at a second injection point  106 . By way of example, the second injection point  106 , represented in  FIG. 2 , is situated in the plane of symmetry (X, Y) of the unit  30 , substantially at equal distance from the proximal  44  and distal  46  ends. 
     The holder  34  preferentially comprising an even number of ribs  52 , an equal number of ribs  52  is preferentially situated on either side of the second injection point  106 . 
     In the example in  FIG. 5 , the second injection point  106  is situated away from the longitudinal grooves  100 ,  102 . According to an alternative embodiment not shown, the second injection point is situated in a longitudinal groove. 
     Preferentially, the third half-mold  96  comprises a series of identical injection channels  104 , each of the channels leading to a third cavity  98 . 
     In a second step for manufacturing the application unit  30 , the first half-mold  80  and the third half-mold  96  are arranged in contact with one another. The compartments  64  of the holder  34 , suitable for receiving the cosmetic product P, are then defined by the ribs  52 , the ridge  58 , the first cavity  84  and the third cavity  98 . 
     The product P in the fluid state is then injected into the second injection volume  99  via the injection channel  104 . The fluid product P first fills the compartment  64  positioned at the second injection point  106 . Via the longitudinal grooves  100 ,  102 , the product P then successively fills, gradually, all the compartments  64  of the area  48 . The second injection volume  99  is then filled entirely with product P. 
     The product P is preferentially injected at a temperature greater than 50° C. so that the material is in the fluid state. So as not to melt the holder  34  during the injection of the product P, the injection temperature of the product P is chosen below a melting point of the material  94 . 
     According to an alternative embodiment of the method described above, the material  94  and the product P are injected into the first volume  88  and into the second volume  99  via a plurality of injection points. 
     Once the injection is complete, the assembly of the first half-mold  80  and the third half-mold  96  is cooled to solidify the product P, forming the mass  36 . The first half-mold  80  and the third half-mold  96  are then separated. The unit  30  obtained is then ejected from the first cavity  84  of the first half-mold  80 , by means not shown. 
     During the injection of the product P, the product is diffused via longitudinal grooves  100 ,  102  formed in the half-mold  96 . Therefore, the flow of product P applies little mechanical strain on the ribs  52 . On the contrary, in the document WO2011/131907, the product P passes from one compartment to another via a groove formed in the holder, at the base of the ribs. During the injection of the product P, the method described above therefore induces less deformation of the ribs than the method in document WO2011/131907. 
     Moreover, the presence of the ridge  58  helps stabilize the ribs  52  during the injection of the product P. 
     The above features therefore make it possible to reduce the percentage of units  30  rejected at the end of the method due to deformation of the holder  34 . 
     The above method for manufacturing the application unit  30  is performed for example by means of a molding press (not shown), as described in the document WO2011/131907. 
     A method for using an application assembly as described above will now be described. Firstly, a user assembles an application unit  30  with the receiving area  20  of the applicator  10 , by particularly fitting the holder  34  onto the rod  16  at the proximal end  44 . The application unit  30  is arranged on the receiving area  20  such that the mass  36  of cosmetic product is situated inside the curve of said receiving area  20 . 
     The user then presses the switch  17  on the gripping handle  12 , so as to supply the element of the rod  16  with electricity. The temperature of the metal casing  18  increases, causing the mass  36  of cosmetic product to soften or melt. In particular, the bulges  70 ,  72  soften or melt. 
     By holding the applicator  10  with the handle  12 , the user then moves the receiving area  20  closer to the eyelashes on which makeup is to be applied. So that the curve of the receiving area  20  substantially molds the shape of the edge of the eyelid, the user positions the eye on the concave side of said receiving area  20 , the axis  14  being arranged substantially perpendicularly to a plane of symmetry of the face. In  FIG. 1 , such a plane of symmetry is a plane (Y, Z). 
     The user then applies the mass  36  on the eyelashes. The product P, softened or molten, is deposited on the eyelashes. In particular, the product P forming the bulges  70 ,  72  is deposited on the eyelashes. 
     After use, the user easily removes the application unit  30  from the rod  16 , by a reverse movement of the assembly movement. If needed, a new application unit  30  is then assembled with the rod  16 . Such a change of application unit can be performed without waiting for the rod  16  to cool. 
     The assembly described above is for example marketed in kit form, comprising, on one hand, an applicator  10 , and, on the other, one or a plurality of application units  30 . 
     According to a first alternative embodiment, all the application units  30  of the same kit are identical. According to a further alternative embodiment, two application units  30  of the same kit comprise a different holder  34  and/or a different mass  36  of cosmetic product P.