Dental floss having low density and method of making same

Abstract

A dental floss comprising a porous PTFE fiber having a density of less than about 0.7 g/cc. The inventive floss is abrasion resistant, grippable and has a soft feel to the hands and a rough feel in the mouth. The floss is made by an extrusion process with non-contact heating during subsequent expansion with amorphous locking.

1 . A dental floss comprising a polytetrafluoroethylene (PTFE) fiber having a denier between 100 and 3500 and a density of less than about 0.7 g/cc.  
     
     
         2 . A dental floss as defined in  claim 1 , wherein said density is less than about 0.6 g/cc.  
     
     
         2 . A dental floss as defined in  claim 1  wherein said density is less than about 0.5 g/cc.  
     
     
         3 . A dental floss as defined in  claim 1 , wherein said density is less than about 0.4 g/cc.  
     
     
         4 . A dental floss as defined in  claim 1 , wherein said density is less than about 0.3 g/cc.  
     
     
         5 . A dental floss as defined in  claim 1 , wherein said density is less than about 0.2 g/cc.  
     
     
         6 . A dental floss as defined in  claim 1 , wherein said density is about 0.6 g/cc.  
     
     
         7 . A dental floss as defined in  claim 1 , wherein said fiber comprises expanded PTFE.  
     
     
         8 . A dental floss as defined in  claim 1 , wherein said fiber has a strength suitable for use as a dental floss.  
     
     
         9 . A dental floss as defined in  claim 1 , wherein said fiber has a strength greater than about 1.5 lbs.  
     
     
         10 . A dental floss as defined in  claim 1 , wherein said fiber has a strength greater than about 2.0 lbs.  
     
     
         11 . A dental floss as defined in  claim 1 , wherein said fiber has a strength greater than about 2.5 lbs.  
     
     
         12 . A dental floss as defined in  claim 1 , wherein said fiber has a strength greater than about 3.0 lbs.  
     
     
         13 . A dental floss as defined in  claim 1 , wherein said fiber has a strength greater than about 5.0 lbs.  
     
     
         14 . A dental floss as defined in  claim 1 , wherein said fiber has a strength greater than about 7.5 lbs.  
     
     
         15 . A dental floss as defined in  claim 1 , wherein said fiber has a strength greater than about 10 lbs.  
     
     
         16 . A dental floss as defined in  claim 1 , wherein said fiber is hollow.  
     
     
         17 . A dental floss as defined in  claim 1 , wherein said fiber has a substantially elliptical cross-section.  
     
     
         18 . A dental floss as defined in  claim 1 , wherein said fiber has a substantially circular cross-section.  
     
     
         19 . A dental floss as defined in  claim 1 , wherein said fiber has a substantially rectangular cross-section.  
     
     
         20 . A dental floss as defined in  claim 1 , wherein said fiber is abrasion resistant.  
     
     
         21 . A dental floss as defined in  claim 1 , wherein said fiber has an average abrasion break strength greater than 2.8×10 −3  lbs per denier.  
     
     
         22 . A dental floss as defined in  claim 1 , wherein said fiber has an average abrasion break strength greater than 3.0×10 −3  lbs per denier.  
     
     
         23 . A dental floss as defined in  claim 1 , wherein said fiber has an average abrasion break strength greater than 4.0×10 −3  lbs per denier.  
     
     
         24 . A dental floss as defined in  claim 1 , wherein said fiber has an average abrasion break strength greater than 5.0×10 −3  lbs per denier.  
     
     
         25 . A dental floss as defined in  claim 1 , wherein said fiber has an average abrasion break strength of about 6.0×10 −3  lbs per denier.  
     
     
         26 . A dental floss as defined, in  claim 1 , wherein said fiber has a strength decay of less than 35%.  
     
     
         27 . A dental floss as defined in  claim 1 , wherein said fiber has a strength decay of less than 10%.  
     
     
         28 . A dental floss as defined in  claim 1 , wherein said fiber has a strength decay of less than 5%.  
     
     
         29 . A dental floss as defined in  claim 1 , wherein there are a plurality of said fibers.  
     
     
         30 . A dental floss as defined in  claim 1 , wherein said fibers contain a filler.  
     
     
         31 . A dental floss as defined in  claim 31 , wherein said fiber has a structure of an expanded PTFE matrix defining interconnected passages and pathways, and said filler is disposed in said passages and pathways.  
     
     
         32 . A dental floss as defined in  claim 31  wherein said fiber has a structure of an expanded PTFE matrix defining interconnected passages and pathways, and said filler is disposed in said expanded PTFE matrix.  
     
     
         33 . A dental floss as defined in  claim 31 , wherein said fiber has a center bore and said filler is disposed in said center bore.  
     
     
         34 . A dental floss as defined in  claim 31  wherein said filler comprises a grip enhancing material.  
     
     
         35 . A dental floss as defined in  claim 31  wherein said filler comprises a bioactive ingredient.  
     
     
         36 . A dental floss as defined in  claim 31  wherein said filler is selected from the group consisting of colorant and a flavorant.  
     
     
         37 . A dental floss as defined in  claim 1  further comprising at least one coating over said fiber.  
     
     
         38 . A dental floss comprising at least one fiber as defined in  claim 1  and at least one other fiber, wherein said one fiber and said at least one other fiber are twisted together or joined together by a binder.  
     
     
         39 . A method of making a dental floss comprising the steps of (a) providing a PTFE resin, (b) extruding said resin to form an extrudate, and (c) expanding said extrudate into a fiber suitable for use as a dental floss.  
     
     
         40 . A method as defined in  claim 41 , wherein said step of extruding said resin includes using a reduction ratio of greater than 150:1.  
     
     
         41 . A method as defined in  claim 41 , wherein said step of extruding said resin includes using a reduction ratio of greater than 200:1.  
     
     
         42 . A method as defined in  claim 41 , wherein said step of extruding said resin includes using a reduction ratio of greater than 250:1.  
     
     
         43 . A method as defined in  claim 41 , wherein said step of extruding said resin includes using a reduction ratio of greater than 300:1.  
     
     
         44 . A method as defined in  claim 41 , wherein said step of extruding said resin includes using a reduction ratio of greater than 500:1.  
     
     
         45 . A method as defined in  claim 41  wherein said step of expanding said extrudate includes simultaneous non-contact heating of said extrudate.  
     
     
         46 . A dental floss as defined in  claim 1  used in a floss device.  
     
     
         47 . A floss device comprising a dental floss as defined in  claim 1   
     
     
         48 . A sewing thread comprising expanded PTFE having a denier between 100 and 3500, a density of less than about 0.7 g/cc and a strength of greater than about 1.5 lbs.  
     
     
         49 . A bearing comprising expanded PTFE having a denier between 100 and 3500, a density of less than about 0.7 g/cc and a strength of greater than about 1.5 lbs.  
     
     
         50 . A bushing comprising expanded PTFE having a denier between 100 and 3500, a density of less than about 0.7 g/cc and a strength of greater than about 1.5 lbs.  
     
     
         51 . A weaving fiber comprising expanded PTFE having a denier between 100 and 3500, a density of less than about 0.7 g/cc and a strength of greater than about 1.5 lbs.  
     
     
         52 . A dental floss comprising an expanded PTFE fiber having surface characteristics of an average roughness of greater than 0.3 microns, a root mean square roughness of greater than 0.35 microns, and a peak to valley distance of greater than 1.7 microns.  
     
     
         53 . A dental floss as defined in  claim 53  wherein said average roughness is about 1.306 microns.  
     
     
         54 . A dental floss as defined in  claim 53  wherein said peak to valley distance is about 1.570 microns  
     
     
         55 . A dental floss as defined in  claim 53  wherein said peak to valley distance is about 6.316 microns.  
     
     
         56 . A method of flossing teeth comprising the steps of (a) providing a dental floss comprising a fiber having a denier between 100 and 3500 and a density of less than about 0.7 g/cc, and (b) inserting said dental floss between the teeth.  
     
     
         57 . A dental floss as defined in  claim 1  wherein said dental floss has a surface with an average roughness of about 1.306 microns, a root mean square roughness of about 1.570 microns, and a peak to valley distance of about 6.316 microns.