Preform for making a non-refillable bottle for non-carbonated liquids

Abstract

A preform for use in blow molding a bottle that is non-refillable and suitable for holding a non-carbonated liquid is provided. The preform may have a transition region, or “step,” on its inner surface. The step may strengthen the region between body and base portions of a bottle that results from blow molding the preform. The body portion of the bottle may be substantially cylindrical. The base portion of the bottle may have a slight inward concavity and may have a substantially constant wall thickness.

What is claimed is:  
     
         1 . A preform for use in blow molding a bottle that is non-refillable and suitable for holding a non-carbonated liquid, the preform comprising: 
 a neck portion;    a shoulder-forming portion connected to the neck portion;    a body-forming portion connected to the shoulder-forming portion;    a transition region connected to the body-forming portion;    a base-forming portion connected to the transition region; and    wherein each of the body-forming portion and the transition region have a respective wall thickness; and 
 the wall thickness of the body-forming portion remains substantially constant; and  
 the wall thickness of the transition region increases from the body-forming portion to the base-forming portion.  
   
     
     
         2 . The preform of  claim 1  wherein a wall thickness of the base-forming portion remains substantially constant from the transition region to a bottom end of the preform.  
     
     
         3 . The preform of  claim 1  wherein a wall thickness of the base-forming portion decreases from the transition region to a bottom end of the preform.  
     
     
         4 . The preform of  claim 1  wherein a wall thickness of the base-forming portion decreases from the transition region to a bottom end of the preform such that the wall thickness at the bottom end is less than the wall thickness of the body-forming portion.  
     
     
         5 . The preform of  claim 1  wherein the neck portion has a threaded finish.  
     
     
         6 . The preform of  claim 1  wherein at least a portion of the base-forming portion has a substantially hemispherical shape.  
     
     
         7 . The preform of  claim 1  wherein the shoulder-forming portion has an inner diameter and an outer diameter that both decrease from the neck portion to the body-forming portion.  
     
     
         8 . A method for producing a one-piece plastic bottle that is non-refillable and suitable for holding a non-carbonated liquid, the method comprising: 
 providing a preform comprising: 
 a neck portion;  
 a shoulder-forming portion connected to the neck portion;  
 a body-forming portion connected to the shoulder-forming portion;  
 a transition region connected to the body-forming portion;  
 a base-forming portion connected to the transition region; and  
 wherein each of the body-forming portion and the transition region have a respective wall thickness; and 
 the wall thickness of the body-forming portion remains substantially constant; and  
 the wall thickness of the transition region increases abruptly from the body-forming portion to the base-forming portion;  
 
   placing the preform in a blow mold;    extending a stretch rod through the body-forming portion of the preform such that it makes contact with a bottom end of the preform;    stretching the preform such that the bottom end of the preform approaches a bottom end of the blow mold, leaving a clearance between the bottom ends of the preform and the blow mold; and    injecting pressurized gas into the preform such that the preform expands to the shape of the blow mold.    
     
     
         9 . A bottle that is non-refillable and suitable for holding a non-carbonated liquid, the bottle comprising: 
 a body portion that is substantially cylindrical having a wall thickness in a range from about 0.15 mm to about 0.24 mm; and    a base portion having multiple radial indentations running from a center portion of the base portion to an outer diameter of the base portion and having a substantially constant wall thickness of about 0.16 mm.    
     
     
         10 . The bottle of  claim 9  wherein the base portion has an inward concavity.  
     
     
         11 . A bottle that is non-refillable and suitable for holding a non-carbonated liquid, the bottle comprising: 
 a body portion that is substantially cylindrical; and    a base portion having a substantially constant wall thickness; wherein: 
 the bottle is made in a blow molding process comprising: 
 providing a preform comprising: 
 a neck portion;  
 a shoulder-forming portion connected to the neck portion;  
 a body-forming portion connected to the shoulder-forming portion;  
 a transition region connected to the body-forming portion;  
 a base-forming portion connected to the transition region; and  
 
 
   wherein each of the body-forming portion and the transition region have a respective wall thickness; and 
 the wall thickness of the body-forming portion remains substantially constant; and  
 the wall thickness of the transition region increases abruptly from the body-forming portion to the base-forming portion; 
 placing the preform in a blow mold;  
 extending a stretch rod through the body-forming portion of the preform such that it makes contact with a bottom end of the preform;  
 stretching the preform such that the bottom end of the preform approaches a bottom end of the blow mold, leaving a clearance between the bottom ends of the preform and the blow mold; and  
 injecting pressurized gas into the preform such that the preform expands to the shape of the blow mold.  
 
   
     
     
         12 . The bottle of  claim 11  wherein the base portion has multiple radial indentations running from a center portion of the base portion to an outer diameter of the base portion.  
     
     
         13 . The bottle of  claim 11  wherein the base portion has an inward concavity.  
     
     
         14 . A method for injection molding a preform for use in blow molding a bottle that is non-refillable and suitable for holding a non-carbonated liquid, the method comprising: 
 providing a neck portion;    providing a shoulder-forming portion connected to the neck portion;    providing a body-forming portion connected to the shoulder-forming portion;    providing a transition region connected to the body-forming portion;    providing a base-forming portion connected to the transition region; and    wherein each of the body-forming portion and the transition region have a respective wall thickness; and 
 the wall thickness of the body-forming portion remains substantially constant; and  
 the wall thickness of the transition region increases from the body-forming portion to the base-forming portion.