Cosmetic product applicator, typically a brush

Abstract

The applicator includes a) a lower part for manually gripping the applicator, b) a central part for resiliently straining the applicator under a manual constraint, c) an upper part bearing an application material and d) an application material anchored to the upper part wherein: 1) the lower and central parts have mean visible cross-sections, denoted respectively S A and S B such that the relative deviation ER 1 =|S A −S B |/S A is less than 0.1, 2) the lower and central parts form a first longitudinal component having an axial direction and a first shape factor L/D between 3 and 7, L and D denoting respectively the largest axial length of and the largest diameter of the first component perpendicular to the axial direction.

1 . Applicator ( 1 ,  1 ′,  1 ″) of a product, typically a brush ( 1 ′) intended to apply a cosmetic product such as a make-up powder to a medium ( 9 ) such as the skin, including a) a so-called lower part ( 2 ) forming a typically rigid means of manually gripping said applicator, b) a so-called central part ( 3 ), anchored to said lower part ( 2 ) by its lower end ( 30 ), forming a means of resiliently straining said applicator under a manual constraint, c) a typically rigid so-called upper part ( 4 ), bearing an application material ( 5 ), said upper part ( 4 ) being anchored to said central part ( 3 ) at its upper end ( 31 ), and d) said application material ( 5 ) anchored by its base ( 51 ) to said upper part ( 4 ), is characterised in that: 
 1) said lower ( 2 ) and central ( 3 ) parts have mean visible cross-sections, denoted respectively S A  and S B  such that the relative deviation ER 1 =|S A −S B |/S A  is less than 0.1,    2) said lower ( 2 ) and central ( 3 ) parts form a first longitudinal component ( 6 ) having an axial direction ( 60 ), said first component ( 6 ) having a first shape factor L/D between 3 and 7, L and D denoting respectively the largest axial dimension or axial length of said first component ( 6 ), and the largest dimension or diameter of said first component ( 6 ) perpendicular to said axial direction ( 60 ),    so as to allow said applicator ( 1 ) to be gripped manually over the whole length L of said first component ( 6 ) and to modulate or control manually, if necessary, said manual constraint, and so to ensure great sensitivity and great delicacy in the application of said product to said medium ( 9 ).    
   
   
       2 . Applicator according to  claim 1  wherein said central ( 3 ) and upper ( 4 ) parts have mean visible cross-sections, denoted S B  and S C  respectively such that the relative deviation ER 2 =|S B −S C |/S B  is less than 0.1, in such a way that said lower ( 2 ), central ( 3 ) and upper ( 4 ) parts of said applicator ( 1 , 1 ′) form a second longitudinal component ( 7 ) of length L′ and of shape factor L′/D>L/D.  
   
   
       3 . Applicator according to  claim 1  wherein said central part ( 3 ) forming said means of resiliently straining said applicator under a manual constraint, includes a material chosen by its nature and/or cross-section, in such a way that said central part ( 3 ) is able to strain when said manual constraint is exerted typically during said application of said product to said medium ( 9 ), then is able to resume its initial shape as soon as said manual constraint ceases.  
   
   
       4 . Applicator according to  claim 1  wherein said strain includes bending.  
   
   
       5 . Applicator according to  claim 1  wherein said strain includes axial compression.  
   
   
       6 . Applicator according to  claim 1  any wherein said lower ( 2 ) and central ( 3 ) parts include or are formed of different materials, a first and a second material respectively, said second material having mechanical characteristics, typically bending and compression moduli lower than the bending or compression moduli of said first material.  
   
   
       7 . Applicator according to  claim 6  wherein said first material is constituted by or includes a plastic material, typically a non-elastomeric thermoplastic material, and wherein said second material is constituted by or includes an elastomer.  
   
   
       8 . Applicator according to  claim 1  wherein said lower ( 2 ) and central ( 3 ) parts include or are formed of one and the same material, typically an elastomer or a polymer mixture including an elastomer.  
   
   
       9 . Applicator according to  claim 1  wherein said lower ( 2 ) and central ( 3 ) parts have one and the same cross-section, and form a typically cylindrical first component ( 6 ).  
   
   
       10 . Applicator according to  claim 1  wherein said central part ( 3 ) has, over all or part of its axial length, a minimum material cross-section S Bm , typically less than 0.5.S A , selected to obtain said strain under manual constraint.  
   
   
       11 . Applicator according to  claim 10  wherein said central part ( 3 ) includes a plurality of N axial or helical threads ( 32 ), each thread ( 32 ) having a cross-section of material S F , such that S Bm  is equal to N.S F , with N typically between 2 and 6.  
   
   
       12 . Applicator according to  claim 10  wherein said central part has an axial profile in the shape of a bobbin ( 33 ), the minimum cross-section of said bobbin ( 33 ) being S Bm .  
   
   
       13 . Applicator according to  claim 10  wherein said central part ( 3 ) has an axial succession or alternation ( 34 ) of full parts ( 34 ) and typically annular hollowed-out annular parts ( 341 ), said hollowed-out parts ( 341 ) having said material cross-section S Bm .  
   
   
       14 . Applicator according to  claim 10  wherein said central part ( 3 ) forms or includes a helical spring ( 35 ), either of metal, or of a plastic material forming a helix of external diameter D H  typically close to D.  
   
   
       15 . Applicator according to  claim 10  wherein said central part ( 3 ) forms a telescopic system ( 36 ) with a central rod ( 360 ) able to penetrate into an axial cavity ( 20 ) formed in said lower part ( 2 ) and a helical spring ( 361 ), either of metal, or of a plastic material, surrounding said central rod ( 360 ).  
   
   
       16 . Applicator according to  claim 1  wherein said lower ( 2 ) and central ( 3 ) parts form a moulded component cast in one piece ( 8 ).  
   
   
       17 . Applicator according to  claim 16  wherein said moulded component cast in one piece is a hollow component, typically of elastomer, and preferably of silicon resin.  
   
   
       18 . Applicator according to  claim 1  wherein, said lower ( 2 ) and central ( 3 ) parts form distinct components anchored by an assembly means ( 61 ) typically by being snapped on, by bonding or by welding.  
   
   
       19 . Applicator according to  claim 1  wherein a) said application material ( 5 ) includes a material absorbent of said cosmetic product, and typically a plurality of bristles ( 50 ), typically parallel and orientated along said axial direction ( 60 ), b) said upper part ( 4 ) forms a double sleeve ( 4 ′), with a first portion ( 40 ) for anchoring to said central part, and with a second portion ( 41 ) for anchoring to said plurality of bristles ( 50 ), so as to form a brush ( 1 ′) or a pencil brush ( 1 ″).  
   
   
       20 . Applicator according to  claim 1  wherein said lower ( 2 ), central ( 3 ) and upper ( 4 ) parts have a round or oval or polygonal external transverse cross-section, typically constant over said length L or L′.  
   
   
       21 . Applicator according to  claim 1  wherein said lower ( 2 ) central ( 3 ) and upper ( 4 ) parts have a flattened external transverse cross-section with a thickness e such that D/e is between 2 and 6, so as the form a two-dimensional applicator able to be housed in a dispenser of said cosmetic product.  
   
   
       22 . Applicator according to  claim 1  wherein said minimum material cross-section S Bm  is a rectangular cross-section of length l and width l′ with a shape factor l/l′ between 2 and 4, in such a way that said applicator ( 1 ,  1 ′,  1 ″) has two distinct levels of resistance to bending depending on whether said bending constraint is exerted parallel to the direction of said length l or said width l′.  
   
   
       23 . Applicator according to  claim 1  wherein said lower part ( 2 ) includes a locking means ( 21 ), typically a sliding bush ( 21 ′), so as to prevent, if need be, said central part ( 3 ) from undergoing said strain under said manual constraint.  
   
   
       24 . Process of manufacturing an applicator according to  claim 7  wherein said component cast in one piece ( 8 ) is formed typically by injection moulding in sequence of said first and second materials.  
   
   
       25 . Process of manufacturing an applicator according to  claim 7  wherein said component cast in one piece ( 8 ) is formed typically by simultaneous injection moulding of said first and second materials, A and B, with pre-set profiles of concentration C A  and C B  along said length L of said component cast in one piece, said profile C A  relating to said first material and said profile C B  relating to said second material, in such a way that said component cast in one piece typically has a minimum resistance to bending in said central part.