Hot fill container having superior crush resistance

Abstract

A hot fill plastic container has a dome portion with a convex outer surface that defines a maximum outer diameter of the container so as to extend outwardly beyond a main body portion of the container. The generally egg-shaped dome portion enhances the crush resistance of the dome and provides a point of contact between containers when they are placed adjacent to one another. A circumferential stiffening groove may be provided near a lower end of the dome portion.

1 . A method of forming a plastic container comprising:
 providing a material suitable for a blow molding process;   disposing the material within a mold cavity configured to form a container having
 a finish portion defining an opening, 
 a substantially cylindrical main body portion having a first maximum diameter in plan view, and 
 a dome portion between the finish portion and main body portion further defining a second maximum diameter in plan view that is greater than the first maximum diameter, and 
 a bottom portion opposite the finish portion, 
 wherein the dome portion in longitudinal section has a convex outer surface comprising a compound curved shape defined by a first convex portion having a first radius of curvature R 1 , a second convex portion having a second radius of curvature R 2 , and a transition region connecting the first convex portion and the second convex portion; and 
   inflating the material within the mold cavity to form the container.   
     
     
         2 . The method of forming a plastic container according to  claim 1 , wherein a ratio of R 1  to R 2  is within a range of 0.3 to 0.9. 
     
     
         3 . The method of making a plastic container according to  claim 2 , wherein the ratio of R 1  to R 2  is within a range of 0.4 to 0.8. 
     
     
         4 . The method of forming a plastic container according to  claim 3 , wherein the ratio of R 1  to R 2  is within a range of 0.5 to 0.7. 
     
     
         5 . The method of forming a plastic container according to  claim 1 , wherein a ratio of R 1  to the second maximum diameter is within a range of 0.4 to 1.2. 
     
     
         6 . The method of forming a plastic container according to  claim 5 , wherein the ratio of R 1  to the second maximum diameter is within a range of 0.55 to 1.05. 
     
     
         7 . The method of forming a plastic container according to  claim 6 , wherein the ratio of R 1  to the second maximum diameter is within a range of 0.7 to 0.9. 
     
     
         8 . The method of forming a plastic container according to  claim 1 , wherein a ratio of the first maximum diameter to the second maximum diameter is within a range of 0.8 to 0.99. 
     
     
         9 . The method of forming a plastic container according to  claim 8 , wherein the ratio of the first maximum diameter to the second maximum diameter is within a range of 0.85 to 0.98. 
     
     
         10 . The method of forming a plastic container according to  claim 9 , wherein the ratio of the first maximum diameter to the second maximum diameter is within a range of 0.9 to 0.97. 
     
     
         11 . The method of forming a plastic container according to claim I, wherein the first convex portion defines a first vertical height and the second convex portion defines a second vertical height, and wherein a ratio of the first vertical height to the second vertical height is within a range of 1.0 to 7.0 
     
     
         12 . The method of forming a plastic container according to  claim 11 , wherein the ratio of the first vertical height to the second vertical height is within a range of 2.0 to 6.0. 
     
     
         13 . The method of forming a plastic container according to  claim 1 , wherein the dome portion is shaped so as to be symmetrical about a longitudinal axis. 
     
     
         14 . The method of forming a plastic container according to  claim 1 , wherein the main body portion further comprises a plurality of cylindrical sidewall portions. 
     
     
         15 . The method of forming a plastic container according to  claim 14 , the plurality of cylindrical sidewall portions separated by a corresponding plurality of stiffening grooves, the stiffening grooves extending around the entire circumference of cylindrical main body portion. 
     
     
         16 . The method of forming a plastic container according to  claim 1 , wherein the mold cavity is further configured to form a circumferential groove in the container proximate to a lowermost end of the dome portion, the circumferential groove extending around an entire circumference of the lowermost end of the dome portion. 
     
     
         17 . The method of forming a plastic container according to  claim 16 , the circumferential groove having a concave radius of curvature R 5  and a maximum depth D G , wherein a ratio of the concave radius of curvature R 5  to the maximum depth D G  is within a range of 0.20 to 1.0. 
     
     
         18 . A method of forming a plastic container comprising:
 providing a material suitable for a blow molding process;   disposing the material within a mold cavity configured to form a container having
 a finish portion defining an opening, 
 a substantially cylindrical main body portion having a first maximum diameter, and 
 a dome portion between the finish portion and the main body portion further defining a second maximum diameter in plan view that is greater than the first maximum diameter, 
 a bottom portion opposite the finish portion, and 
 a circumferential groove defined proximate to a lowermost end of the dome portion, the circumferential groove extending around an entire circumference of the lowermost end of the dome portion, 
 wherein the dome portion has a convex outer surface in longitudinal section comprising a compound curved shape defined by a first convex portion having a first radius of curvature R 1 , a second convex portion having a second radius of curvature R 2 , and a transition region connecting the first convex portion and the second convex portion, and 
 wherein the second maximum diameter is defined by the second convex portion; and 
   inflating the material within the mold cavity to form the container.   
     
     
         19 . The method of forming a plastic container according to  claim 18 , the main body portion further comprising a plurality of cylindrical sidewall portions separated by a corresponding plurality of stiffening grooves, the stiffening grooves extending around the entire circumference of cylindrical main body portion. 
     
     
         20 . The method of forming a plastic container according to  claim 18 , the circumferential groove having a concave radius of curvature R 5  and a maximum depth D G , wherein a ratio of R 5  to D G  is within a range of 0.20 to 1.0.