Lightweight container and method of manufacture

Abstract

A hollow plastic container includes an open finish, a closed bottom and a sidewall connecting the finish to the bottom. The sidewall is ultra thin, having a radial wall thickness of not more than 0.008 inch, preferably in the range of about 0.003 to 0.004 inch. The container preferably is blow molded from a preform having a wall thickness such that a stretch ratio of eight to ten is obtained during the blowing operation. The preform may be heated prior to blow molding to achieve sidewall crystallization at a level of 28% to 35%.

1 . A hollow plastic container for hot fill applications having an open finish, a closed bottom and a sidewall connecting said finish to said bottom, said container being blow molded from a preform, said sidewall having a stretch ratio of eight to ten as compared with said preform and having a wall thickness of not more than 0.008 inch.  
     
     
         2 . The container set forth in  claim 1  wherein said sidewall has a crystallization level in the range of 28% to 35%.  
     
     
         3 . A method of making a container for hot fill applications, which includes the steps of: 
 (a) providing a preform having a sidewall with a first radial thickness, and    (b) blow molding said preform into a container having a second radial wall thickness of not more than 0.008 inch, and in such a way that said second wall thickness has a stretch ratio of eight to ten as compared with said first wall thickness.    
     
     
         4 . The method set forth in  claim 3  that includes the step, between said steps (a) and (b), of: (c) crystallizing said sidewall of said preform to a crystallization level in the range of 28% to 35%.  
     
     
         5 . The method set forth in  claim 3  that includes the step, prior to said step (b), of: (c) hot filling said container with a fluid product at a temperature of about 185° F.  
     
     
         6 . A hollow plastic container that includes an open finish, a closed bottom and a sidewall connecting said finish to said bottom, said sidewall having a radial wall thickness of not more than 0.008 inch.  
     
     
         7 . The container set forth in  claim 6  wherein said sidewall has a thickness of not more than about 0.004 inch.  
     
     
         8 . The container set forth in  claim 7  wherein said sidewall has a thickness in the range of about 0.003 to 0.004 inch.  
     
     
         9 . A preform assembly for blow molding a plastic container, which includes: 
 a molded plastic preform having a body and a neck, said body having a wall thickness of not more than about 0.08 inch, and    a plastic finish ring formed separately from said preform and externally secured to said neck.    
     
     
         10 . The preform assembly set forth in  claim 9  wherein said wall thickness is in the range of about 0.04 to 0.05 inch.  
     
     
         11 . A preform for blow molding a plastic container, which includes a neck and a body with a closed bottom, said body having a wall thickness of not more than about 0.08 inch.  
     
     
         12 . The preform set forth in  claim 11  wherein said wall thickness is in the range of about 0.04 to 0.05 inch.  
     
     
         13 . The preform set forth in  claim 11  wherein said body is crystallized to a level of 28% to 35%.  
     
     
         14 . A method of making a hollow plastic container that includes the steps of: 
 (a) molding a preform having a neck with an open end, a closed bottom and a sidewall with a thickness of not more than 0.08 inch, and    (b) blow molding said sidewall and bottom to form a container having a wall thickness less than 0.008 inch.    
     
     
         15 . The method set forth in  claim 14  wherein said preform in said step (a) has a wall thickness in the range of 0.04 to 0.05 inch, and said container in said step (b) has a thickness in the range of 0.003 to 0.004 inch.  
     
     
         16 . The method set forth in  claim 14  including the additional step, prior to or subsequent to said step (b), of: (c) attaching a finish ring to said neck.  
     
     
         17 . The method set forth in  claim 14  that includes the additional step, between said steps (a) and (b), of: (c) crystallizing said sidewall of said preform to a crystallization level in the range of 28% to 35%.  
     
     
         18 . The method set forth in  claim 14  that includes the additional step, following said step (b), of: (c) hot filling said container with a liquid product at a temperature of about 185° F.