Patent Publication Number: US-2018049542-A1

Title: Cosmetic applicator having fibres

Description:
The present invention relates to an applicator for applying a cosmetic product to human keratin materials, in particular the eyelashes and/or eyebrows, the nails or the lips, and to a device having the applicator and a reservoir of cosmetic product. The invention also relates to a cosmetic treatment process with the aid of the applicator. 
     The invention is concerned more particularly with applicators that have a stem and, at one end thereof, an applicator member having fibres for applying the product to the keratin materials. 
     A large number of applicators of this type, in which the brush has a core formed by two arms of a metal wire that are twisted together and grip fibres, or have fibres that form a bundle of substantially parallel fibres, are known. 
     Patent Applications FR 2 898 782, FR 2 847 436, BE 638 856 describe an applicator having hollow cylindrical fibres with a circular or square section. 
     European Patent Application EP 2 796 532 relates to fibres having at least one depression and having a helical groove. 
     Applications US 2005/0268415 and EP 0 130 611 relate to fibres having two longitudinal cavities. 
     International Application WO 2012/137134 describes a fibre with a symmetric shape along its longitudinal axis and a hollow cross section. The fibre has a hollow body in the form of a cylinder of revolution and, in cross section, six identical protruding reliefs, with a substantially rectangular shape, that extend towards the outside from the body and are evenly distributed around the body. 
     European Patent Application EP 1 034 722 relates to an applicator having fibres. Each fibre has a central core that has at least two fringes on its surface. The latter can be evenly distributed around the core of the fibre and be curved. Preferably, the central core is hollow. 
     There is a need to further improve applicators for applying a cosmetic product to human keratin materials. 
     Therefore, a subject of the invention is an applicator for applying a cosmetic product, having:
         a stem, and   an applicator member carried by the stem, having a plurality of fibres, each having:
           a hollow cylindrical body, and   at least one longitudinal rib attached to the body by its base,
 
each fibre being without axial symmetry in cross section and being inscribed in a circle of diameter D 2 , such that the ratio D 2 /D 1  is less than or equal to 1.75, D 1  being the greatest outside transverse dimension of the body.
   
               

     The hollow cylindrical body has a closed contour in cross section. 
     The fact that the fibres have a hollow cylindrical body makes it easier for them to deform, this taking place in particular when the fibres are being fixed to the applicator member. The fact that the fibres are hollow can also increase the retention of product. 
     The presence of one or more longitudinal ribs can also help to improve the retention of the product, in particular by capillary action, and influence the orientation of the fibre while it is being fixed to the core, in the case of a mascara brush. 
     The particular cross section of the fibres according to the invention is particularly advantageous when the fibres are used to manufacture a mascara brush, being clamped between two metal strands that are twisted together. In this case, the fibres according to the invention tend to be oriented in random directions, this making it possible to break the spiral effect on the brush and to obtain improved performance in terms of loading and separation of the eyelashes and/or eyebrows. 
     The ratio D 2 /D 1  may be less than or equal to 1.5. 
     Each fibre may have at least two ribs, better still at least three ribs. The number of ribs may be less than or equal to 10, better still less than or equal to 5. Preferably, at least one rib extends inside the body. This can make it possible to limit the deformation of the fibre by crushing and thus to modify the behaviour of the fibre, depending on its orientation relative to the strands of the core which grip it. 
     Preferably, at least one rib extends outside the body. The fact that the fibres have at least one external rib makes it possible to have surface reliefs which allow better retention of the cosmetic product. 
     The applicator may have at least one rib extending inside the body and at least one rib extending towards the outside of the body. In a variant, all the ribs extend inside the body or all the ribs extend outside the body. 
     The ribs may all be the same shape. In a variant, at least one rib is a different shape from the others. 
     The rib or ribs may extend along the entire length of the fibres along an axis parallel to the longitudinal axis of the fibre. The rib or ribs is/are preferably continuous along the fibre. 
     Preferably, each fibre has an identical cross section along its entire length. This allows the fibre to have constant mechanical properties along its entire length, and makes it easier to produce by extrusion. 
     The ribs may be evenly distributed around the body. 
     The rib or ribs may have a substantially polygonal shape in cross section, in particular a triangular, rectangular or square shape, or have a rounded shape, in particular a semicircular shape. 
     The thickness of the rib, measured radially, in cross section at its base connected to the body at its radially outermost free end, may be between 0.01 and 0.06 mm. 
     The greatest width of the rib, measured in cross section perpendicularly to the thickness, may be between 0.01 and 0.06 mm. 
     The hollow body of the fibre may define a single cavity. 
     The thickness of the wall of the hollow body may be constant. 
     It is possible for the outer surface of the body not to have a concavity, when the fibre is viewed with its longitudinal axis rectilinear. 
     The body may have a cross section which is substantially in the form of a regular or irregular polygon, circular or non-circular, in particular an oval, elliptical, kidney-shaped, pear-shaped or cruciform cross section. 
     The largest dimension D 1  of the body in cross section may be between 0.07 and 0.25 mm. 
     The fibres may be made of a plastics material, preferably of a thermoplastic material, in particular polyamide (PA), elastomer, polybutylene terephthalate (PBT), rubber, or mixtures thereof, in particular a mixture of PA, PBT and rubber or elastomer and PA. 
     The fibres are preferably made of a single material. 
     The applicator may have fibres with different shapes. For example, the applicator has two types of fibre, each type of fibre being according to the invention. 
     The different types of fibre may be mixed at random or in an organized manner on the applicator. For example, a first part of the applicator has only a first type of fibre and a second part of the applicator has only a second type of fibre. 
     Although the invention applies advantageously to a twisted wire brush, the applicator may alternatively have a bundle of substantially parallel fibres and faint a brush of the baleen type or a fine brush. The stem of the applicator may then be substantially parallel to the fibres. In a variant, as in the case of a twisted wire brush, the stem is substantially perpendicular to the fibres. 
     A further subject of the invention is a packaging and application device having:
         a reservoir containing the cosmetic product to be applied,   an applicator according to the invention, as defined above.       

     A further subject of the invention is a cosmetic treatment process comprising the step of bringing an applicator according to the invention into contact with human keratin materials, in particular into contact with the eyelashes, the eyebrows, the nails, the lips or the skin, depending on the nature of the product. 
    
    
     
       The invention may be better understood from reading the following detailed description of non-limiting illustrative embodiments thereof and from examining the appended drawing, in which: 
         FIG. 1  schematically shows an example of a packaging and application device, 
         FIGS. 2 to 7  illustrate variants of fibres in cross section, and 
         FIG. 8  is an elevation view of another example of an applicator. 
     
    
    
     The packaging and application device  1  shown in  FIG. 1  has a container  2  containing a cosmetic product P to be applied, in particular to the eyelashes or the eyebrows, for example mascara, and an applicator  3  having a stem  4  of longitudinal axis X, provided at one end  4   a  with an applicator member  5  and at the opposite end with a gripping member  6  that likewise serves to close the container  2 . The latter has a neck  7  which is externally threaded so as to allow the gripping member  6  to be screwed on. 
     A wiping member  8  is fixed inside the neck  7  in order to wipe the stem.  4  and the applicator member  5  as they are withdrawn from the container  2 . This wiping member  8  has a flexible lip  9  that defines a circular wiping orifice, the diameter of which corresponds more or less to that of the stem  4 . 
     Of course, the invention is not limited to the use of a particular wiping member and further wiping members can be used, for example a wiping member with a wavy lip and/or having one or more slits. 
     In the example illustrated, the stem  4  is rectilinear but it could be curved without departing from the scope of the present invention. 
     In the example in question, the applicator member  5  has a core  10  formed in a conventional manner by two twisted metal strands, this core  10  being fixed at one end in a housing in the stem  4 , being for example force-fitted into this housing. 
     The applicator member  5  has fibres  11  which are held in a clamped manner between the twisted strands of the core  10 . 
     As can be seen in  FIG. 2  in particular, these fibres  11  each have a hollow body  13  with a cylindrical shape, through which a central cavity  15  passes longitudinally and which is provided with at least one longitudinal rib  17 . 
     Each fibre  11  is inscribed in a circle C, the diameter D 2  of which is such that the ratio D 2 /D 1  is less than or equal to 1.75, better still less than or equal to 1.5, D 1  being the greatest outside transverse dimension of the body  13 . 
     In the example illustrated in  FIG. 2 , the fibre  11  has a body  13  in the form of a cylinder of revolution and three identical ribs  17  with a substantially rectangular shape that are evenly distributed angularly on the outside of the body  13 . 
     The cross section of the fibre  11  is not symmetric about its centre, but in the example illustrated the fibre is the image of itself by rotation through 120°. 
     The body  13  has a closed circular section, with a constant thickness e between its outer surface  21  and inner surface  19 , for example between 0.01 and 0.08 mm, and with an outside diameter D 1  of between 0.07 and 0.25 mm. 
     The longitudinal ribs  17  extend along the entire length of the fibres  11  and are continuous. 
     The maximum thickness h of each rib  17  taken, in cross section, at its base  23  connected to the body  13  at its end  25  is between 0.01 and 0.08 mm. 
     The greatest width L of each rib  17 , in cross section, is between 0.01 and 0.08 mm. 
     While they are being clamped between the metal strands of the core, the fibres  11  are oriented differently depending on the orientation of their section with respect to the strands. A random modification of the orientation of the fibres can thus be obtained, and the spiral effect that is detrimental to the performance of the applicator can be weakened. 
     The example in  FIG. 3  differs from the one in  FIG. 2  in that the ribs  17  are each substantially semicircular in shape. 
     The example in  FIG. 4  differs from the one in  FIG. 3  in that the body  13  of the fibre  11  has a polygonal cross section, in this case hexagonal. The ribs  17  are present for example on every other side, and are centred on their respective sides. 
     The example in  FIG. 5  differs from the one in  FIG. 2  in that the fibres  11  have ribs  17   a  and  17   b  with different shapes and in that the body  13  has a non-circular, in particular elliptical, shape in cross section. The rib  17   a  has a rounded, in particular semi-oval, shape and the ribs  17   b  have a substantially triangular shape, being situated away from the rib  17   a . The ribs  17   a  and  17   b  can have different greatest widths L a  and L b  and different maximum thicknesses h a  and h b . 
     The ribs  17   a  and  17   b  are positioned on either side of the major axis M of the body  13 . 
     The example in  FIG. 6  differs from the one in  FIG. 2  in that the ribs  17  extend towards the inside of the body  13 . The diameter D 1  is equal to the diameter D 2 . 
     Such ribs  17  make it possible to modify the crushing of the fibre in some directions. 
     The example in  FIG. 7  differs from the one in  FIG. 2  in that it has both ribs  17   e  that extend towards the outside of the body  13  and ribs  17   i  that extend towards the inside of the body  13 . The ribs  17   i  are different shapes, one having for example, as illustrated, a triangular section and the other having a rectangular section. Such a fibre makes it possible to combine the effects associated with the presence of the internal and external ribs, that is to say to allow good retention of product and to break the spiral effect. 
       FIG. 8  illustrates an applicator having a stem  4  of longitudinal axis X, provided at one end  4   a  with an applicator member  5  and at the opposite end with a gripping member  6 , the applicator member  5  being formed by a bundle of substantially parallel fibres  11 . 
     The invention is not limited to the exemplary embodiments which have just been described, and the characteristics of the various examples can be combined with one another within variants that are not illustrated. 
     The invention is not limited to the shapes of ribs illustrated. 
     The body of the fibres may have a circular, oval or polygonal shape, but is not limited to these shapes. 
     The expression “having a” should be understood as being synonymous with “comprising at least one”, unless specified to the contrary.