Abstract:
An applicator for liquid or pasty media, in particular for decorative cosmetics such as mascara has a rod-shaped reinforcing core of a first plastic material which is surrounded at least in the region of its front end by a support sleeve of a second plastic material. The support sleeve has a plurality of radially outwardly projecting fingers which are integrally formed on the support sleeve and also consist of the second plastic material. Several fingers which are distributed over the periphery of the support sleeve form a finger collar and a plurality of finger collars with identical finger number are disposed one behind the other in the longitudinal direction of the support sleeve. A particular combination of parameters for the bristles leads to improved combing and application properties.

Description:
BACKGROUND OF THE INVENTION 
   This application is the national stage of PCT/EP02/00371 filed on Jan. 16, 2002 and also claims Paris Convention priority of DE 101 02 219.0 
   The invention concerns an applicator for liquid or pasty media, in particular for decorative cosmetics such as mascara, comprising a rod-shaped reinforcing core of a first plastic material which is surrounded, at least in the region of its front end, by a support sleeve of a second plastic material, which comprises a plurality of radially outwardly projecting fingers which are integrally formed on the support sleeve and are made from the second plastic material, wherein several fingers, which are distributed over the periphery of the support sleeve, form a finger collar and wherein a plurality of N finger collars having the same number of fingers n are disposed one behind the other in the longitudinal direction of the support sleeve. 
   Such an applicator can be used in different fields of application. Application of mascara is described by way of example below. The inventive applicator can also be used for coloring hair stands or applying pharmaceuticals. 
   An applicator for mascara should assure that the mascara can be applied in a simple and uniform fashion. Towards this end, the applicator must initially comb the eyelashes before applying the mascara thereby orienting them in the desired fashion. Moreover, the applicator should be able to receive sufficient mascara to be able to color all eyelashes without having to insert the applicator several times into the mascara supply container. To ensure that the mascara is applied uniformly and without splashing, one must ensure that the applicator does not carry an excessive amount of mascara. For this reason, the applicator is usually wiped on the mascara supply container when being removed from the container. Since the applicator is formed as a freely protruding component with a handle at one end, it must have sufficient stability to be able to safely accommodate the forces acting during use, without breaking. The applicator must, however, be sufficiently flexible to adjust to the curvature of the eyelids and to sufficiently bend in response to improper use to prevent injuries to the eye region of the user. 
   Up to now, a mascara applicator has conventionally been produced from several wires (U.S. Pat. No. 4,982,838) between which a plurality of short bristles is disposed. The bristles are fixed between the wires through twisting of the wires. A twisted applicator brush of this type has the substantial disadvantage that, due to the compact configuration of the bristles, during use, a considerable portion of the mascara is retained in the gaps formed between the bristles in which impurities, e.g. spores or bacteria may develop. Moreover, uniform combing of the eyelashes is not possible with such an applicator brush due to the plurality of densely packed bristles, since the bristles cannot engage with the eyelashes to produce a combing effect. Moreover, production of a twisted applicator brush is relatively expensive since the wires and the bristles must be produced individually and the bristles must subsequently be twisted into the wires requiring constructively demanding systems. The bristle ends must also be deburred and ground to avoid sharp-edged ends and eliminate any associated risk of injury. An additional disadvantage of twisted applicator brushes is that the metal soul formed by the twisted metal wires can kink during use which renders the applicator brush useless and also presents a great risk to the eye region of the user. 
   WO 00/54623 discloses an applicator developed to avoid the disadvantages of twisted applicator brushes with bristle stock. That applicator has a reinforcing rod-shaped core onto which an elastomeric plastic jacket is injected in the shape of a support sleeve with integrally formed fingers which project radially outwardly. The fingers have a cross-section which tapers towards their free ends. In this configuration, the fingers have a larger mutual separation at their free ends than in their lower foot regions where they are connected to the support sleeve. Due to the relatively large separation between the free support ends, no or only a small amount of mascara is received in the region of the tips which may be nearly completely removed by the conventional wiper. The tip region of the fingers therefore contains substantially no mascara during use of the applicator and merely combs the eyelashes before they contact the mascara provided in the foot region of the fingers. The relatively small separation between neighboring fingers in their foot region permits accommodation of a sufficiently large amount of mascara to avoid repeated insertion of the applicator into the supply container. It has turned out, however, that the combing action and the application of mascara depend on the constructive design of the applicator and, in particular, on the number, design and configuration of the fingers and not all applicators of the mentioned type obtain satisfactory results. 
   It is therefore the underlying purpose of the invention to further develop an applicator of this type to ensure an improved combing action and also good and uniform application of the medium to be applied. 
   SUMMARY OF THE INVENTION 
   This object is achieved in accordance with the invention with an applicator of the above-mentioned type by the parameter combination recited in the independent claim. 
   All finger collars should have the same number of fingers which are preferably uniformly distributed about the periphery of the support sleeve, i.e. have identical mutual angular separations. The inventive applicator has n fingers per finger collar, wherein n is between of 8 and 16. An even number n of fingers (8, 10, 12 or 16 fingers) is preferred. 
   While the number n of fingers per finger collar determines the density of the fingers in the peripheral direction, the density of the fingers in the longitudinal direction of the support sleeve and thereby of the applicator is determined by the number N of the finger collars disposed, one behind the other, in the axial direction. The separation between neighboring finger collars should be within a predetermined range and the number of finger collars should not be excessively high to maintain easy handling of the applicator and to provide good mascara application, even when the eyelashes are relatively short. The invention therefore provides that the applicator has between 14 and 30 finger collars and in particular between 20 and 27 finger collars. 
   The fingers of all finger collars may have the same sizes. It has turned out to be advantageous to form finger collars with fingers of reduced size at the front and rear ends of the applicator. Although these finger collars with smaller fingers are included in the number N of finger collars, the following embodiments refer to the fingers of a normal finger collar in the central region. The length l of the fingers, i.e. the degree by which the finger projects past the support sleeve in a radial direction, is between 1.5 mm to 3.0 mm. 
   The mutual separation s 1  of neighboring finger collars is a parameter which considerably influences the combing action and mascara application. In accordance with the invention, the separation s 1  measured between the free ends of similar fingers of neighboring finger collars should be between 0.6 mm and 1.5 mm. 
   The fingers of neighboring finger collars in the region of the finger feet, i.e. in the connecting region between the fingers and support sleeve, should have a clearance separation s 2  of between 0.2 mm and 0.5 mm. 
   A first embodiment of the invention provides that the applicator has the following parameter combination: 
   
     
       
             
             
             
           
         
             
                 
                 
             
           
           
             
                 
               I. 
               n = 10 
             
             
                 
               II. 
               N = 27 
             
             
                 
               III. 
               l = 2.4 mm 
             
             
                 
               IV. 
               s 1  = 0.95 mm 
             
             
                 
               V. 
               s 2  = 0.25 mm 
             
             
                 
                 
             
           
        
       
     
   
   In a further possible embodiment, the parameters, in combination, assume the following values: 
   
     
       
             
             
             
           
         
             
                 
                 
             
           
           
             
                 
               I. 
               n = 12 
             
             
                 
               II. 
               N = 22 
             
             
                 
               III. 
               l = 2.4 mm 
             
             
                 
               IV. 
               s 1  = 1.2 mm 
             
             
                 
               V. 
               s 2  = 0.42 mm 
             
             
                 
                 
             
           
        
       
     
   
   The applicator has a substantially circular cylindrical configuration, i.e. an envelope surface of the applicator has a circular cross-section which is either constant along the entire length of the finger field or, as mentioned above, is only reduced in its end regions. For practical handling of the applicator, it has turned out to be advantageous when its outer diameter D is between 6.0 mm and 10.0 mm and in particular 8.0 mm. 
   The reinforcing, rod-shaped core preferably has a circular cross-section of a diameter of between 1.5 mm and 2.5 mm and in particular 2.0 mm. The core may have a constant cross-section along its entire length. However, the core preferably tapers at its front end. 
   The rod-shaped core may be straight or alternatively be curved in which case a “banana shape”, i.e. a continuous curvature in one direction is preferred. 
   The wall thickness a of the support sleeve substantially defines the elastic bearing of the fingers and thereby their flexibility. The radial wall thickness a of the support sleeve should be between 0.3 mm and 1.0 mm, and in particular 0.6 mm, in the region where the core has a constant cross-section. When the core tapers at its front end, the wall thickness a of the support sleeve is correspondingly enlarged in this region such that the outer contour of the support sleeve is circularly cylindrical. 
   The applicator is preferably produced in a two-component method. In a first step, the rod-shaped core is injected from a first plastic material and an elastomeric second plastic material is subsequently injected onto the core in a second step to form the support sleeve and fingers. 
   The overall axial length L of the support sleeve should be between 20.0 mm and 35.0 mm and preferably 25.0 mm. 
   In accordance with the invention, the front region of the applicator may have increased flexibility. This can be effected when the front end section of the support sleeve projects past the front end of the core by a value v, such that the front end section of the applicator is completely made from the elastomeric second plastic material. The value v can be between 1.0 mm and 8.0 mm and is preferably 3.0 mm. 
   In the most simple geometric design, the middle axes of the fingers of each finger collar lie in a common plane which extends perpendicular to the longitudinal direction of the applicator such that the individual fingers are not offset in the longitudinal direction of the support sleeve or of the applicator. Alternatively, at least one finger of a finger collar is offset from the other fingers of the finger collar by a value v F  in the longitudinal direction of the support sleeve. In a preferred embodiment of the invention, every second finger of the finger collar is offset such that the fingers of a finger collar lie in two parallel planes, separated in a longitudinal direction of the support sleeve and extending perpendicular to the longitudinal direction of the support sleeve. The shift v F  is preferably given as a function of the foot diameter d F  of the fingers, i.e. as v F =f×d F , wherein f is a factor in the range between 0 (no offset) and 1.5 (maximum offset). 
   In addition to offsetting individual fingers within a finger collar, neighboring finger collars can also be offset relative to each other in the peripheral direction by an angle α wherein α should be between 0° and 10°. If α=0°, i.e. no angular offset is provided, the tips of similar fingers of the finger collars lie on a straight line extending in the longitudinal direction of the applicator. If neighboring finger collars are angularly offset, the tips of similar fingers of the finger collars are disposed along a circulating spiral line. 
   In a preferred embodiment of the invention, each finger is conical and has a foot diameter d F  in a range between 0.4 mm and 1.0 mm, in particular 0.68 mm. The fingers are preferably rounded at their free ends, wherein a radius R of the rounding is in the range between 0.02 mm and 0.2 mm and in particular 0.05 mm. 
   Further details and features of the invention can be extracted from the following description of embodiments with reference to the drawing. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  shows a side view of an applicator in accordance with a basic structure; 
       FIG. 2  shows a longitudinal section through the applicator of  FIG. 1 ; 
       FIG. 3  shows the section III-III of  FIG. 2 ; 
       FIG. 4  shows a side view of sections of the applicator of  FIG. 1 ; 
       FIG. 5  shows a longitudinal section of sections of the applicator of  FIG. 1 ; 
       FIG. 6  shows a longitudinal section through a finger in an enlarged scale; 
       FIG. 7  shows a side view of sections of an applicator with alternative finger configuration; 
       FIG. 8  shows a side view of a first embodiment of an inventive applicator; 
       FIG. 9  shows a longitudinal section through the applicator of  FIG. 8 ; 
       FIG. 10  shows the section X-X of  FIG. 9 ; 
       FIG. 11  shows a side view of a second embodiment of the inventive applicator; 
       FIG. 12  shows a longitudinal section through the applicator of  FIG. 11 ; and 
       FIG. 13  shows the section XIII-XIII of  FIG. 12 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 through 3  show the basic structure of an applicator  10  for explaining the individual parameters in connection with  FIGS. 4 through 7 . 
   The applicator  10  has a rod-shaped reinforcing core  11  with a circular cross-section ( FIG. 3 ) which has, at its rear end, connecting elements  11   b  for mounting to a receiving part (not shown). The core  11  cross-section tapers in its front end region  11   e  and bears, at its front end  11   d , a widened head  11   c  which serves for positive mounting of the core  11  together with recesses  11   a  formed in the central section of the core  11 . The core  11  consists of a first plastic material and is produced in the first phase of a two-component injection molding method. 
   In a second phase of the two-component injection molding method, a support sleeve  12  of an elastomeric second plastic material is injected onto the rod-shaped core  11 , which is firmly connected to the core  11  via engagement in the recesses  11   a  and the head  11   e  of the core  11 . The outer contour of the support sleeve  12  is circularly cylindrical and consequently has a constant wall thickness in a central and rear section  12   a  where it surrounds the middle region of the core  11 . The wall thickness steadily increases in the tapering region  11   c  of the core  11  to compensate for the cross-sectional reduction of the core  11 . A front end section  12   b  of the support sleeve  12  projects past the front end  11   d  of the core  11  by an amount v ( FIG. 2 ) such that the front end section  12   b  is completely formed from the elastomeric, second plastic material. 
   Radially outwardly projecting fingers  13 , which conically taper towards their free ends, are integrally formed on the outer side of the support sleeve  12  and are also made from the elastomeric second plastic material. The fingers  13  are arranged in the form of a total of N finger collars, K 1 , K 2 , K 3 , K 4 , . . . K 26 , K 27  which are disposed at equal separations behind each other in the longitudinal direction of the support sleeve  12 . Each finger collar K i  (see  FIG. 4 ) comprises a certain number n of fingers  13 , which each lie in a plane E i  extending perpendicular to the longitudinal direction of the support sleeve  12 , of which only one is indicated in  FIG. 4 , and are uniformly distributed at equal angular separations about the periphery of the support sleeve  12 . In the embodiment shown in  FIGS. 1 through 3 , a total of N=27 finger collars are provided, each having n=10 fingers  13 . The configuration and design of the fingers  13  is identical for most finger collars. Only the first finger collar K 1  formed at the rear end and the two last finger collars K 26  and K 27  disposed at the front end of the support sleeve  12  have fingers of reduced size while the finger collars K 2  through K 25  have identical configuration. The statements concerning the size of the fingers  13  always refer to finger collars of identical structure. 
   As can be seen from  FIG. 2 , the support sleeve  12  has an overall length L wherein the core  11  projects past the support sleeve  12  at its rear end and has the connecting elements  11   b.    
     FIG. 4  shows that the tips of the fingers  13  of any finger collar K i  lie in a plane E i  extending perpendicular to the longitudinal direction of the support sleeve  12 , wherein the planes of neighboring finger collars have a constant mutual separation. 
     FIG. 7  shows an alternative embodiment wherein, viewed in the peripheral direction, every second finger  13  of the finger collar K i  is offset relative to the other fingers of the finger collar in the longitudinal direction of the support sleeve  12 . As a result, half of the fingers of the finger collar K i  are disposed with their tips in a first plane E i1  extending perpendicular to the longitudinal direction of the support sleeve  12  and the other half of the fingers are disposed in a plane E i2  which is parallel thereto and offset in the longitudinal direction of the support sleeve  12  by an amount v F . The separation between the planes E i1  and E i2 , i.e. the shift v F  of the fingers in the longitudinal direction of the support sleeve  12  is the same for all finger collars. Furthermore, the plane E i2  may have a separation v k  from the plane E (i−1)1  of the neighboring finger collar which is equal to the shift v F . 
   As can be seen in  FIG. 7 , the individual finger collars are mutually aligned in the longitudinal direction of the support sleeve  12 , i.e. have no angular offset in the peripheral direction of the support sleeve  12 . The tips of corresponding fingers of the individual finger collars therefore lie on straight connecting lines which extend parallel to the longitudinal axis of the support sleeve  12 , of which  FIG. 7  exemplarily shows the three lines x 1 , x 2  and x 3 . 
     FIG. 5  shows the geometrical relationships in the central region of the applicator  10 . The core  11  section of constant circular cross-section has an outer diameter d and is surrounded by the support sleeve  12  having a wall thickness a. The outer side of the support sleeve  12  bears the fingers  13  which project outwardly and which are conical, i.e. taper conically towards the free ends with a radial length l. The overall diameter d of an envelope surface of the applicator is therefore:
   D=d +2 a +2 l.   
   The associated fingers  13  of neighboring finger collars have a mutual separation s 1  at their free ends while the finger feet of associated fingers of neighboring finger collars have a clearance separation s 2  ( FIG. 5 ). The fingers  13  have the shape of a circular cone and the base or connecting surface of the finger has a diameter d F  ( FIG. 6 ). The fingers are rounded at their outer free ends with a radius R. 
   The following ranges have proven to be useful for the individual parameters:
     1. overall diameter D of the applicator: 6.0 mm to 10.0 mm   2. core diameter d: 1.5 mm to 2.5 mm   3. wall thickness a of the support sleeve: 0.3 mm to 1.0 mm   4. finger length l: 1.5 mm to 3.0 mm   5. separation s 1  of the finger tips of neighboring finger collars: 0.6 mm to 1.5 mm   6. separation s 2  of the finger feet of neighboring finger collars: 0.2 mm to 0.5 mm   7. overall length L of the support sleeve: 20.0 mm to 35.0 mm   8. length v of the front region which is not reinforced: 1.0 mm to 8.0 mm   9. number n of fingers per finger collar: 8 to 16, in particular 8, 10, 12 or 16   10. number N of finger collars: 14 to 30   11. diameter d F  of the finger foot: 0.4 mm to 1.0 mm   12. rounding radius R of the finger tip: 0.02 mm to 0.2 mm   13. axial offset v F  of the fingers of a finger collar v F =f×d F , wherein 0≦f≦1.5   14. offset angle α of neighboring finger collars in the peripheral direction: 0°≦α≦10°.   

     FIGS. 8 through 10  show a first concrete embodiment of an applicator  10 . It differs from the basic structure shown in  FIGS. 1 through 3  by having a special parameter combination, wherein a total of N=27 finger collars are provided of which the rear first finger collar K 1  and the two front collars K 26  and k 27  are reduced in size. All other finger collars K 2  to K 25  have the same configuration with n=10 fingers uniformly distributed over the periphery of the support sleeve  12 , wherein every other finger of each finger collar is offset relative to the other fingers by v F =s 1 /2=f×d F =0.48 mm, wherein f=0.7. The exact parameter values are given in the following list: 
   
     
       
             
             
             
             
           
         
             
                 
                 
             
           
           
             
                 
               D = 8.0 mm 
               s 2  = 0.25 mm 
               d F  = 0.68 mm 
             
             
                 
               d = 2.0 mm 
               L = 25.0 mm 
               v F  = 0.48 mm 
             
             
                 
               a = 0.6 mm 
               v = 3.0 mm 
               R = 0.05 mm 
             
             
                 
               l = 2.4 mm 
               n = 10 
               α = 0° 
             
             
                 
               s 1  = 0.95 mm 
               N = 27 
             
             
                 
                 
             
           
        
       
     
   
     FIGS. 11 through 13  show a further embodiment with an advantageous parameter combination, wherein the rear first two finger collars K 1  and K 2  and the front last finger collar K 22  have fingers of reduced size and five additional small fingers  18  are formed at the front end of the support sleeve  12  and are distributed about the periphery of the support sleeve  12  but are not part of a finger collar. Also herein, every other finger of the finger collar is offset by v F =s 1 /2=f×d F =0.48 mm in the longitudinal direction of the support sleeve  12  relative to the other fingers. 
   The exact parameter values are given in the following list: 
   
     
       
             
             
             
             
           
         
             
                 
                 
             
           
           
             
                 
               D = 8.0 mm 
               s 2  = 0.42 mm 
               d F  = 0.68 mm 
             
             
                 
               d = 2.0 mm 
               L = 25.0 mm 
               v F  = 0.48 mm 
             
             
                 
               a = 0.6 mm 
               v = 3.0 mm 
               R = 0.05 mm 
             
             
                 
               l = 2.4 mm 
               n = 12 
               α = 0° 
             
             
                 
               s 1  = 1.2 mm 
               N = 22