Toothbrush bristle and method for manufacturing such a bristle

Abstract

A method for manufacturing filaments for personal hygiene articles is described. The filaments are provided with a surface structure with at least one surface recess such as dimples and/or pittings. The filament includes at least a portion made of a material soluble by a corrosive agent and is covered in part with a cover layer stable to the corrosive agent such that a surface portion of the filament body substantially corresponding to the at least one surface recess is uncovered. The filament body is contacted with the corrosive agent for a limited time to create the surface recess in the uncovered surface portion.

1 . A filament for use in a personal hygiene implement, the filament comprising:
 a filament body made, in part, by a material soluble by a corrosive agent;   a cover layer made, in part, by a material stable to the corrosive agent, the filament body being within the cover layer, the cover layer having surface features thereon.   
     
     
         2 . The filament of  claim 1 , wherein the surface features comprise dimples in the cover layer. 
     
     
         3 . The filament of  claim 2 , wherein the dimples extend through the thickness of the cover layer such that the filament body is exposed. 
     
     
         4 . The filament of  claim 1 , wherein the cover layer and the filament body comprise holes therethrough, wherein the holes of the filament body and the holes of the cover layer are aligned. 
     
     
         5 . The filament of  claim 4 , wherein an oral care agent is disposed within the holes of the filament body and/or the holes of the cover layer. 
     
     
         6 . The filament of  claim 4 , wherein the holes of the filament body are connected to a longitudinal cavity in the filament body. 
     
     
         7 . The filament of  claim 1 , wherein the cover layer comprises a first material and a second material, wherein the first material is soluble by a corrosive agent and wherein the second material is stable to the corrosive agent. 
     
     
         8 . The filament of  claim 1 , wherein the cover layer comprises a photo active material. 
     
     
         9 . A method for manufacturing a filament for a toothbrush wherein the filament is given a surface structure, the method comprising the steps of:
 obtaining a filament body;   providing a cover layer over the filament body;   creating uncovered portions of the filament body; and   contacting the filament body with a corrosive agent for a limited time to create a surface recess in the uncovered portions of the filament body.   
     
     
         10 . The method according to  claim 9 , covering the filament body completely with a continuous cover layer and removing a portion of the cover layer to provide at least one void. 
     
     
         11 . The method according to  claim 10 , further comprising the steps of providing a photosensitive material for the continuous cover layer; irradiating a first portion of the cover layer with light or radiation; exposing a second portion of the cover layer to no radiation; and
 removing the first portion or the second portion of the cover layer.   
     
     
         12 . The method of  claim 11 , further comprising the step of contacting the first portion or the second portion of the cover layer with a photographic developer. 
     
     
         13 . The method of  claim 9 , further comprising the steps of inhomogeneously co-extruding the cover layer onto the filament body, and removing a portion of the cover layer to expose the filament body. 
     
     
         14 . The method of  claim 11 , further comprising the step of cutting the filament body into a plurality of filaments. 
     
     
         15 . The method of  claim 9 , further comprising the step of providing a void in the cover layer using at least one tool. 
     
     
         16 . The method according to  claim 9 , further comprising the steps of shielding a first section of the filament body; shielding a second section of the filament body, wherein the first section and the second section are spaced from each other; irradiating an unshielded section of the filament between the first section and the second section to remove the cover layer in the unshielded section; and contacting the filament body with the corrosive agent for a limited time in the unshielded section to create a reduced diameter section. 
     
     
         17 . The method of  claim 9 , further comprising the step of providing a tapered tip to the filament body.