Toothbrush handle having an inner cavity

Abstract

A personal care article, such as a toothbrush handle having an inner cavity.

What is claimed is: 
     
         1 . A toothbrush handle comprising:
 a) a terminal end, connector end, outer surface, inner cavity, and longitudinal axis;   b) the inner cavity having a surface defining a cross-sectional area; wherein the inner cavity has at least one of a greater cross-sectional area, bordered by two lesser cross-sectional areas along the longitudinal axis of the toothbrush or a lesser cross sectional area bordered by two greater cross-sectional areas along the longitudinal axis of the toothbrush;   c) the outer surface defining an outer surface cross-sectional area;   d) a wall formed from the outer cavity surface and inner cavity surface;   e) the toothbrush handle comprising a single unitary component;   wherein the difference between the outer surface cross-sectional area and the inner cavity surface cross-sectional area varies less than 25% over at least 50% of the toothbrush handle length along the longitudinal axis.   
     
     
         2 . The toothbrush handle of  claim 1 , wherein the square root of the outer surface cross-sectional area varies proportionally to the square root of the inner cavity cross-sectional area along the longitudinal axis of the toothbrush. 
     
     
         3 . The toothbrush handle of  claim 2 , wherein the square root of the inner cavity surface cross-sectional area varies proportionally less than 5% to the variations in the square root of the outer surface cross-sectional area along the longitudinal axis of the toothbrush handle. 
     
     
         4 . The toothbrush handle of  claim 1 , wherein the in the thickness of the toothbrush handle wall varies in inverse proportion to the square root of the outer surface cross-sectional area. 
     
     
         5 . The toothbrush handle of  claim 1 , wherein the average wall thickness is from about 0.5 to about 5.0 mm. 
     
     
         6 . The toothbrush handle of  claim 1 , wherein the inner cavity is open to the outer surface of the toothbrush handle. 
     
     
         7 . The toothbrush handle of  claim 1 , wherein the inner cavity is sealed and is not open to the toothbrush handle outer surface. 
     
     
         8 . The toothbrush handle of  claim 1  having a connector. 
     
     
         9 . The toothbrush handle of  claim 7 , wherein the inner cavity extends into the connector. 
     
     
         10 . The toothbrush handle of  claim 9 , wherein the inner cavity comprises a connection feature. 
     
     
         11 . The toothbrush handle of  claim 1  having a specific gravity below about 0.60 g/cm 3  and wherein the toothbrush handle deforms less than about 10 mm under a 5.0N force applied as determined by ASTM D 790. 
     
     
         12 . The toothbrush handle of  claim 1 , wherein the outer surface cross-sectional area of at least one of the terminal end or connector end is less than the largest cross-sectional area of the inner cavity. 
     
     
         13 . The toothbrush handle of  claim 1 , wherein outer surface cross-sectional area of at least one of the terminal end or connector end is less than the smallest cross-sectional area of the inner cavity. 
     
     
         14 . The toothbrush handle of  claim 1 , wherein the toothbrush handle comprises at least one of polypropylene, polyethylene terapthalate, polyethylene terapthalate glycol, high-density polyethylene, low-density polyethylene, or polystyrene. 
     
     
         15 . A toothbrush handle comprising:
 a) a terminal end, connector end, outer surface, inner cavity, and longitudinal axis;   b) the inner cavity having a surface defining a cross-sectional area; wherein the inner cavity has at least one of a greater cross-sectional area, bordered by two lesser cross-sectional areas along the longitudinal axis of the toothbrush or a lesser cross sectional area bordered by two greater cross-sectional areas along the longitudinal axis of the toothbrush;   c) the outer surface defining an outer surface cross-sectional area;   d) a wall formed from the outer cavity surface and inner cavity surface;   e) the toothbrush handle comprising a single unitary component;   wherein the toothbrush handle comprises two or more material layers.   
     
     
         16 . The toothbrush handle of  claim 15 , wherein the square root of the outer surface cross-sectional area varies proportionally to the square root of the inner cavity cross-sectional area along the longitudinal axis of the toothbrush. 
     
     
         17 . The toothbrush handle of  claim 15 , having a first material layer and a second material layer, wherein the toothbrush handle outer surface comprises the first material layer and the second material layer. 
     
     
         18 . The toothbrush handle of  claim 17 , wherein the second material comprises a label. 
     
     
         19 . The toothbrush handle of  claim 15 , having a first material layer and a second material layer, wherein the second material layer is encompassed within the first layer and the second material layer thickness varies less than about 20% along the length of the toothbrush handle longitudinal axis. 
     
     
         20 . The toothbrush handle of  claim 15 , having a first material layer and a second material layer, wherein the second material layer is encompassed within the first layer and is visible through the first material layer.