Pressurized refill container resistant to standing ring cracking

Abstract

Refillable plastic container includes a top portion, a sidewall portion defining an interior and a longitudinal axis and a base portion extending downwardly of the sidewall portion and defining a closed bottom. The base portion has a heel extending downwardly and inwardly of the sidewall portion at an angle relative the longitudinal axis and having a substantially frustoconical shape. A standing ring extends from heel and defines a support surface of the container. A central dome projects upwardly of the standing ring toward the interior. The central dome portion has a convex surface relative the interior.

What is claimed is: 
     
         1 . A refillable plastic container comprising:
 a top portion defining an opening;   a sidewall portion extending downwardly of the top portion, the sidewall portion defining an interior and a longitudinal axis; and   a base portion extending downwardly of the sidewall portion and defining a closed bottom, the base portion comprising:
 a heel extending downwardly and inwardly of the sidewall portion at an angle relative the longitudinal axis, the heel having a substantially frustoconical shape, 
 a standing ring extending from the heel and defining a support surface of the container, 
 a central dome extending upwardly of the standing ring toward the interior, the dome having a convex surface relative the interior. 
   
     
     
         2 . The container of  claim 1 , wherein the sidewall portion is cylindrical and generally circular in plan view. 
     
     
         3 . The container of  claim 1 , wherein the base portion further comprises an outer support wall extending between the sidewall portion and the heel. 
     
     
         4 . The container of  claim 1 , wherein the angle of the heel relative the longitudinal axis is within a range of about 35 degrees to about 45 degrees. 
     
     
         5 . The container of  claim 1 , wherein the angle of the heel relative the longitudinal axis is about 40 degrees. 
     
     
         6 . The container of  claim 1 , wherein the standing ring is concave relative the interior in transverse cross-section. 
     
     
         7 . The container of  claim 1 , wherein the standing ring is arcuate in transverse cross-section. 
     
     
         8 . The container of  claim 1 , wherein the standing ring has a radius of less than about 1.5 inches in transverse cross-section. 
     
     
         9 . The container of  claim 1 , wherein the standing ring has a wall thickness configured to resist flexing of the standing ring during a sterilization and refill process. 
     
     
         10 . The container of  claim 1 , wherein the standing ring has a wall thickness at least 10 percent greater than a wall thickness of the standing ring of a substantially similar bottle having a radiused heel in transverse cross section. 
     
     
         11 . The container of  claim 9 , wherein the wall thickness of the standing ring is within a range of about 2.4 mm to about 2.6 mm. 
     
     
         12 . The container of  claim 1 , wherein the standing ring extends directly from the heel. 
     
     
         13 . The container of  claim 1 , wherein the central dome extends directly from the standing ring. 
     
     
         14 . The container of  claim 1 , wherein the central dome has a substantially hemispherical shape. 
     
     
         15 . The container of  claim 1 , wherein the container can withstand at least 20 refill cycles in a commercially acceptable caustic wash without failure in the standing ring portion. 
     
     
         16 . The container of  claim 1 , wherein the container comprises polyester. 
     
     
         17 . The container of  claim 15 , wherein the container comprises a polyester comprising polyethylene terephthalate (PET). 
     
     
         18 . A base portion for a refillable plastic container having a top portion, sidewall portion, and the base portion, the base portion comprising:
 a heel extending downwardly and inwardly of the sidewall portion at an angle relative the longitudinal axis, the heel having a substantially frustoconical shape;   a standing ring extending from the heel and defining a support surface of the container;   a central dome extending upwardly of the standing ring toward the interior, the central dome having a convex surface relative the interior.   
     
     
         19 . The base portion of  claim 18 , wherein the sidewall portion is cylindrical and generally circular in plan view. 
     
     
         20 . The base portion of  claim 18 , wherein the base portion further comprises an outer support wall extending between the sidewall portion and the heel. 
     
     
         21 . The base portion of  claim 18 , wherein the angle of the heel relative the longitudinal axis is within a range of about 35 degrees to about 45 degrees. 
     
     
         22 . The base portion of  claim 18 , wherein the angle of the heel relative the longitudinal axis is about 40 degrees. 
     
     
         23 . The base portion of  claim 18 , wherein the standing ring is concave relative the interior in transverse cross-section. 
     
     
         24 . The base portion of  claim 18 , wherein the standing ring is arcuate in transverse cross-section. 
     
     
         25 . The base portion of  claim 18 , wherein the standing ring has a radius of less than about 1.5 inches in transverse cross-section. 
     
     
         26 . The base portion of any of  claim 18 , wherein the standing ring has a wall thickness configured to resist flexing of the standing ring during a sterilization and refill process. 
     
     
         27 . The base portion of  claim 18 , wherein the standing ring has a wall thickness of at least 10 percent greater than a wall thickness of a standing ring of a substantially similar bottle having a radiused heel in transverse cross section. 
     
     
         28 . The base portion of  claim 26 , wherein the wall thickness of the standing ring is within a range of about 2.4 mm to about 2.6 mm. 
     
     
         29 . The base portion of  claim 18 , wherein the standing ring extends directly from the heel. 
     
     
         30 . The base portion of  claim 18 , wherein the central dome extends directly from the standing ring. 
     
     
         31 . The base portion of  claim 18 , wherein the central dome has a substantially hemispherical shape. 
     
     
         32 . The base portion of  claim 18 , wherein the container can withstand at 20 refill cycles in a commercially acceptable caustic wash without failure in the standing ring. 
     
     
         33 . The base portion of  claim 18 , wherein the container comprises polyester. 
     
     
         34 . The base portion of  claim 32 , wherein the container comprises a polyester comprising polyethylene terephthalate (PET).